Abstract
Aims: Air quality changes with human health risk assessment were investigated. Methods: The measurement results obtained by the Regional Environmental Protection Inspectorate (REPI) in Kraków and our deposited particulate-matter (PM) analysis, as well as United States Environmental Protection Agency (USEPA) methodology of risk assessment were used in the study. Results: Annual pollutant contents kept decreasing, with the exception of O3. However, the permissible annual levels were exceeded in the cases of PM10, PM2.5, and NO2. Increased contents of SO2, CO, C6H6, PM10, and PM2.5, as well as of As, Pb, Cd, Ni, and polycyclic aromatic hydrocarbons (PAHs) in PM particles during winter months indicated that house heating was the source of pollution. Due to no significant change in the monthly NO2 contents, this measurement was used as an indicator of traffic sources of pollution. In winter months, the allowable 24 h PM2.5 and PM10 contents were constantly exceeded. PM was identified as the most significant air pollutant. Enrichment factors revealed that deposited PM was enriched with heavy metals. The potential ecological risk (ERI) was determined to be very high for Cd, considerable for Zn, and low for As, Co, Cr, Cu, Ni, Pb, and Tl. The total non-carcinogenic risk indices (HQ) for both adults (HQ = 15.0) and children (HQ = 26.4) exceeded the acceptable value of 1. The total carcinogenic risk indices (CR) for both adults (CR = 1.51 × 10−4) and children (CR = 1.77 × 10−4) exceeded the acceptable level of 1 × 10−4. Conclusions: In the years 2005–2020, a general decreasing tendency of annual pollutant contents was observed. However, the permissible contaminant contents were still exceeded. PM2.5, BaP, PM10, and NO2 were determined as the most dangerous pollutants in inhalational pathway.
Keywords: air pollution, air quality index, particulate matter, enrichment factors, health risk assessment, COVID-19
1. Introduction
For several years, Kraków has been said to represent an example of the cities with poor air quality. Kraków has suffered high concentrations of gaseous and dust pollutants in air since the 1950s, and that was associated with the development of industry and operation of combined heat and power plants and steelworks in Kraków [1]. However, since the 1990s, a decrease of air pollution has been observed, owing to the implementation of control technologies with lower emission standards and decentralisation of the government, as well as privatisation processes [1,2,3]. Nevertheless, the World Health Organisation (WHO) placed Kraków at position no. 11 on the list of the 50 most polluted cities of the European Union [4]. Later, according to the 2018 update, Kraków was moved to position no. 8 on that list [5]. The current air pollution condition in Kraków results from the operation of power plants, low emissions [6,7], and traffic [8]. Moreover, the city is surrounded by communes, where poor-quality coal stoves are still the dominant house heating systems. Consequently, the inflow of emissions from neighbouring towns causes a deterioration of air quality in Kraków. Despite the fact that a total ban on burning coal, wood, and other solid fuels in boiler houses, stoves, and fireplaces was imposed in the city of Kraków on 1 September 2019 [9], air pollution continues to be excessive. The condition of air in Kraków was widely investigated under several research projects [10,11,12,13,14,15,16,17,18]. Moreover, air quality studies in this particular city are not easy due to its geographical and topographical condition. Kraków is located in southern part of Poland and borders the Carpathian Foothills in the south, Silesian-Kraków Upland in the west, Kraków Upland in the north, and Sandomierz Basin in the east (Figure 1) [19]. In addition, within the administrative boundaries of Kraków, uplands are observed in northern, western, and southern parts of the city, while lowlands are observed in eastern Kraków. The maximum height amplitude in the investigated area is approximately 140 m above mean sea level (MSL) between the Vistula River Valley in the east and Sowiniec Hill in the west [19]. The location of Kraków in the Vistula River valley, dividing the city into the northern and southern parts, determines the shape of the observed wind rose [20] (Figure S1). West winds are dominating, and east ones occur with high frequency [20]. Land relief in a concave form defines the latitudinal direction of city ventilation [20] (Figure S2). Existing urban and industrial buildings reduce the speed of winds and modify the wind directions [20].
Figure 1.
Geographic location of Kraków in Poland and elevation changes of the city (modified after [19]).
Air pollution is nowadays considered to be one of the most important factors affecting human health. Poor air quality causes damages in the respiratory tract and cardiovascular systems [21,22,23,24,25], as well as an increase of premature death rates in populations [26,27,28,29,30]. Specific attention was lately paid to particulate matter (PM). PM particles can adsorb other harmful substances on their surfaces [31], and consequently, they can cause additional adverse health effects after entering human bodies [32]. Street dust was described as the most effective and sensitive indicator of urban environment pollution, especially by heavy metals [33]. The enrichment of dust with heavy metals can be caused by anthropogenic sources, including means of transportation, industrial plants, fossil fuel burning, or construction works [34,35].
In recent years, the residents of Kraków have been trying to resolve effectively the poor air quality problem. The movement was started in 2012 by the implementation of several social campaigns undertaken by the Kraków Smog Alert, a non-government organisation [3]. However, evident changes required not only considerable expenditures, but also time measured in years. Currently, the residents and visitors are affected by adverse health effects due to poor air quality inhaled. According to the authors’ best knowledge, the first attempts at calculating human health risk among the Kraków inhabitants were described in research conducted by Samek [16], Gruszecka and Wdowin [36], Pachurka et al. [37], and Gruszecka-Kosowska [38].
Taking the above into consideration, the objectives of our present study were selected as follows: (1) to determine the changes occurring in general air quality in Kraków in the last 15 years (2005–2020), (2) to identify the most significant air pollutants, from the viewpoint of health, and (3) to assess human health risk for the Kraków inhabitants, arising from the exposure to the ambient-air contaminants.
2. Materials and Methods
2.1. Concentration of Pollutants in the Ambient Air in Kraków
To perform long-term and short-term air-quality change analyses, the authors investigated the results of the air monitoring measurements obtained by the Regional Environmental Protection Inspectorate (REPI) in Kraków (2005–2020) collected from up to nine monitoring stations located in the city (Table S1). The measurement results have been published in the Internet since 2007 [39], while those concerning pollutant concentrations in 2005 and 2006 were taken from the REPI reports [40,41,42,43,44,45].
The following pollutants measured by the REPI were investigated in the present study: benzene (C6H6), carbon oxide (CO), nitrogen dioxide (NO2), sulphur dioxide (SO2), and particulate matters PM10 and PM2.5, as well as the following pollutants measured in PM10 particles (PM10): arsenic (As), lead (Pb), cadmium (Cd), nickel (Ni), benzo[a]anthracene (BaA), benzo[a]pyrene (BaP), benzo[b]fluoranthene (BbF), benzo[j]fluoranthene (BjF), benzo[k]fluoranthene (BkF), and dibenzo[a,h]anthracene (DBahA).
2.2. Air Quality Standards
To determine the air quality in Kraków, the REPI measurement results were compared to the Polish permissible levels of pollutants determined in the Regulation of the Minister of the Environment concerning the levels of certain substances in the air [46]. Based on that legal act, the permissible annual concentrations of air contaminants were determined as follows: C6H6: 5 µg/m3, NO2: 40 µg/m3, SO2: 125 µg/m3, CO: 10,000 µg/m3, PM10: 40 µg/m3, PM2.5: 25 µg/m3 (20 µg/m3 since 1 January 2020), and Pb (PM10): 0.5 µg/m3. The Polish regulation also determined 24 h (24 h) permissible levels for the following contaminants: SO2 (125 µg/m3) and PM10 (50 µg/m3). Since the Polish regulation did not specify any permissible 24 h PM2.5 content, that value was adopted from the World Health Organisation air quality guidelines and was set at 25 µg/m3 [47]. One hour (1 h) permissible contaminant levels were also defined in the Polish regulation for NO2 and SO2 and were equal to 200 µg/m3 and 350 µg/m3, respectively, as well as an eight-hour (8 h) permissible level for O3 equal to 120 µg/m3. For other heavy metals in PM10, also the European Union and the United Kingdom recommended values were used [48]. The target values were set as follows: As (PM10): 6 ng/m3, Cd (PM10): 5 ng/m3, and Ni (PM10): 20 ng/m3.
2.3. Polish Air Quality Index
The air quality index (AQI) is a widely recognised index that is easily understood by the public, due to the presentation of air contamination on a numerical scale, using a colour-intensity coding. In our study, 1 h air quality measurements were used for a better visualisation of the Polish AQI index values. As to individual pollutants, the air quality index is defined by the ranges of 1 h concentrations of pollutants (Table S2) [39]. The Polish AQI index also reflects negative health effects, in direct proportion to the AQI scale growth (Table S3) [39].
2.4. Enrichment Factors of PM with PHEs
Particulate matter (PM) becomes a crucial contaminant since it contains other pollutants adsorbed on particle surfaces, and special attention is paid to heavy metals in that respect. Thus, in our study, the enrichment factors of particulate matter, with potentially harmful elements (PHEs), were calculated. Since the Polish Regional Environmental Protection Inspectorate (REPI) measured only four heavy metals (As, Cd, Ni, and Pb) in PM particles, our analysis also concerned selected concentrations of PHEs, identified in deposited PM particles by Gruszecka-Kosowska and Wdowin [36]. As to the enrichment factors, our specific calculations refer to the PHE contents in deposited particulate matter, as presented in Gruszecka-Kosowska [49].
The following enrichment factors of PM with PHEs were investigated: geoaccumulation index (Igeo), contamination factor (CF), enrichment factor (EF), ecological risk index (ERI), and modified hazard quotient (mHQ). The Igeo and CF factors determine the accumulation of elements in relation to background values. In our study, local geochemical values were taken from Kabata-Pendias [50]. The EF factor describes element enrichment, in respect of the elements with a low variability of occurrence, and Fe was chosen for that purpose in our study. To calculate the EF values, both concentrations from upper continental crust [51] and local geochemical values [50] were taken. The ERI and mHQ indices determine ecological risk by comparing metal concentrations to the synoptic adverse ecological effect distributions, in respect of slightly differing threshold levels [52]. Detailed descriptions of enrichment indices applied in the present study are given in Table S4, as presented in Gruszecka-Kosowska [49].
2.5. Health Risk Assessment
Health risk was assessed based on the United States Environmental Protection Agency methodology [53]. In our research, the resident scenario was analysed for adults and children (0–6 years). The following exposure pathways for the residents of Kraków were investigated in our research: inhalation of the contaminants, being present in the ambient air, inhalation of potentially toxic elements (PHEs), being present in deposited particulate matter (PM) particles, accidental ingestion of PHEs, being present in deposited PM particles, and dermal contact with PHEs, being present in deposited PM particles. The contents of pollutants in the ambient air were obtained from the data collected by the Regional Environmental Protection Inspectorate (REPI) in Kraków [39] as mean values, upon averaging the measurement results of the period from 2005 to 2020, as well as from the data originating from up to nine monitoring stations located in the city. The PHE contents in deposited PM were taken from research conducted by Gruszecka-Kosowska and Wdowin [36] on PHEs in deposited PM, as mean values of the investigated elements, as described in Gruszecka-Kosowska [49].
To estimate the daily intake of contaminates via the inhalation route, based on the REPI measurement exposure concentration (ECinh air), the values were calculated according to Equation (1) [54], while the average daily dose (ADDinh air) values were calculated according to Equation (2) [53], depending on the availability of the toxicological data required for risk value calculations:
| ECinh air = (Cair × ET × EF × ED)/AT | (1) |
| ADDinh air = (Cair × IRinh × EF × ED)/(BW × AT). | (2) |
For estimation of the daily intake of the PHEs being present in redeposited PM particles via the inhalation route, the exposure concentration (ECinh PM) values were calculated based on Equation (3) [55], while the average daily dose (ADDinh PM) values were calculated according to Equation (4) [56], depending on the availability of the toxicological data needed for risk values calculations:
| ECinh PM = (CPM × ET × EF × ED)/(PEF × AT) | (3) |
| ADDinh PM = (CPM × IRinh × AF × EF × ED)/(PEF × BW × AT). | (4) |
To estimate the daily intake of PHEs being present in redeposited PM particles via the ingestion route, the average daily dose (ADDing PM) values were calculated according to Equation (5) [55]:
| ADDing PM = (CPM × CF × IRing × FI × EF × ED × RBA)/(BW × AT). | (5) |
To estimate the daily intake of PHEs being present in redeposited PM particles via the dermal contact route, the average daily dose (ADDder PM) values were calculated according to Equation (6) [55]:
| ADDder PM = (CPM × CF × AF × ABSd × EF × ED × EV × SA)/(BW × AT), | (6) |
where EC, exposure concentration (mg/m3); ADD, average daily dose (mg/kg-day); Cair, contaminant concentration in air (measured values were converted to mg/m3); CPM, concentration of each element in deposited PM (mg/kg); IR, intake rate (m3/day or mg/kg); PEF, particle emission factor (m3/kg); CF, unit conversion factor (10−6 kg/mg); FI, fraction ingested from contaminated source (unitless); RBA, relative bioavailability factor (unitless); AF, adherence factor of PM to skin (mg/cm2 event); ABSd, dermal absorption factor (unitless); EV, event frequency (events/day); SA, skin surface area available for contact (cm2); ET, exposure time (h/day or days/year); EF, exposure frequency (days/year); ED, exposure duration (years; BW, body weight (kg); AT, averaging time (ED in years × 365 days/year × 24 h/day in hours or ED in years × 365 days/year in days; for non-carcinogens ED = 24 years, for carcinogens ED = 70 years [54]).
The exposure parameters used for the risk assessment calculations under the resident scenario are given in Table S5.
To determine the non-carcinogenic and carcinogenic risks for the residents of Kraków in four investigated exposure pathways, the HQ and CR values were calculated, respectively. The values of hazard indices (HQ) were calculated using Equations (7) and Equations (8) [55]. The values of carcinogenic risk (CR) were calculated using Equations (9) and Equations (10) [55].
| HQ = EC/RfC, | (7) |
| HQ = ADD/RfD, | (8) |
| CR = EC × IUR, | (9) |
| CR = ADD × SF, | (10) |
where HQ, hazard quotient (unitless); CR, carcinogenic risk (unitless); ADD, average daily dose (mg/kg-day), EC, exposure concentration (mg/m3), RfC, reference concentration (mg/m3); RfD, reference dose (mg/kg-day); IUR, inhalation unit risk (mg/m3); SF, slope factor (mg/kg-day)−1.
The values of toxicological parameters, used for the calculations of the resident scenario risk assessment, are given in Table S6.
The target risk value was set to be equal to 1 (HQ = 1) for non-carcinogenic risk, for both the individual contaminants being investigated (individual HQ values) and total non-carcinogenic risk, which was defined as the sum of all the calculated HQ values. As for carcinogenic risk, the acceptable risk level was set to be equal to 1 × 10−6 for an individual contaminant and equal to 1 × 10−4 for the sum of carcinogenic contaminants [53,57].
3. Results
3.1. Pollutant Content and Air Quality Changes in 2005–2020
Upon our analysis of the mean annual investigated pollutant concentrations collected from all the monitoring stations, in the period of the last 15 years (Table S7), we observed a general tendency of content decrease, with the exception of O3, whose increased levels were identified. Despite the above-described general tendency, permissible annual contents of the investigated pollutants (if determined) were exceeded in all the investigated years in the cases of PM10 and PM2.5 (except for 2019) and in the case of NO2 (except for 2014 and 2019). However, excessive C6H6 levels of annual permissible rates were determined in 2005 and 2006 (Table S7). For our further investigations, 2018 was chosen as the most recent year, with a significant excess of permissible levels of pollutants. The investigated pollutants contents, which were calculated as the mean monthly values of the data originating from all the monitoring stations in Kraków, are presented in Table S8. Higher contents of SO2, CO, C6H6, PM10, PM2.5, heavy metals, and polycyclic aromatic hydrocarbons (PAHs) were observed in winter months in comparison to summer months. In addition, 24 h air pollutant contents, calculated as mean values, collected from all the monitoring stations in Kraków, were investigated. March 2018 and July 2018 were chosen as model winter and summer months, respectively to show the most spectacular (the highest) daily values of investigated pollutants. Upon our analysis of 24 h selected pollutant contents in March 2018 (Table S9), it was observed that the PM2.5 contents exceeded the WHO recommended value of 25 µg/m3 in all days; as to PM10, the same happened in the first 11 and last nine days of March. Our analysis of 24 h selected pollutant contents in July 2018 (Table S10) was concluded with the observation that in the summer months, an excess of permissible level of 120 µg/m3 was observed only in the case of O3.
We applied the Polish AQI index to present hourly air-pollutant rate changes, with correlated health information. March 2018 was chosen for our analysis as the month with generally significant pollutant contents. The worst situation was observed in the cases of PM2.5 (Table 1) and PM10 (Table 2), as well as C6H6 (Table 3). In March, the Polish AQI index was determined to range from average to very bad for PM2.5 and PM10, and from moderate to average for C6H6. The general air quality index for NO2 (Table 4) was estimated to be very good to good, with several hours of moderate air quality. As to NO2, the increase of its contents was observed in the morning and evening hours. O3 displayed increased contents during the whole day (Table 5), from 18 to 19 March 2018. In the cases of SO2 (Table S11) and CO (Table S12), a very good air quality index was determined for the whole month of March 2018, based on mean 24 h concentrations.
Table 1.
Daily and hourly PM2.5 content changes, with the hourly Polish air quality index (AQI), average values for Kraków, March 2018 [39] (weekend marking in grey).
| PM2.5 | |||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Day | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 |
| Hour | |||||||||||||||||||||||||||||||
| 01:00 | 80 | 73 | 52 | 184 | 149 | 118 | 109 | 77 | 95 | 93 | 93 | 37 | 8 | 58 | 46 | 52 | 14 | 18 | 15 | 33 | 65 | 62 | 119 | 105 | 85 | 56 | 85 | 24 | 52 | 64 | 37 |
| 02:00 | 87 | 86 | 54 | 185 | 156 | 119 | 100 | 73 | 101 | 98 | 96 | 48 | 5 | 62 | 51 | 46 | 11 | 14 | 15 | 29 | 63 | 57 | 123 | 110 | 87 | 58 | 84 | 28 | 52 | 61 | 33 |
| 03:00 | 100 | 83 | 57 | 182 | 159 | 130 | 102 | 74 | 102 | 93 | 94 | 37 | 5 | 57 | 54 | 44 | 11 | 16 | 16 | 32 | 71 | 52 | 127 | 115 | 91 | 58 | 83 | 23 | 42 | 56 | 35 |
| 04:00 | 109 | 91 | 60 | 184 | 146 | 131 | 95 | 74 | 90 | 90 | 92 | 26 | 5 | 56 | 48 | 48 | 12 | 14 | 16 | 31 | 81 | 45 | 122 | 111 | 98 | 58 | 81 | 26 | 47 | 42 | 32 |
| 05:00 | 112 | 93 | 70 | 179 | 142 | 122 | 103 | 74 | 87 | 93 | 92 | 20 | 5 | 53 | 32 | 45 | 10 | 13 | 15 | 31 | 86 | 41 | 112 | 110 | 101 | 67 | 77 | 26 | 37 | 42 | 32 |
| 06:00 | 111 | 94 | 78 | 161 | 124 | 119 | 100 | 77 | 98 | 92 | 89 | 20 | 8 | 58 | 29 | 41 | 10 | 14 | 15 | 36 | 90 | 41 | 103 | 109 | 97 | 68 | 72 | 35 | 34 | 45 | 29 |
| 07:00 | 117 | 90 | 87 | 160 | 144 | 106 | 85 | 79 | 100 | 93 | 83 | 19 | 12 | 59 | 27 | 38 | 13 | 14 | 18 | 40 | 59 | 37 | 97 | 104 | 94 | 70 | 75 | 40 | 34 | 46 | 28 |
| 08:00 | 144 | 98 | 88 | 151 | 154 | 96 | 93 | 74 | 90 | 96 | 86 | 26 | 19 | 58 | 24 | 38 | 17 | 16 | 18 | 36 | 18 | 32 | 90 | 94 | 91 | 76 | 83 | 42 | 37 | 38 | 28 |
| 09:00 | 113 | 117 | 75 | 137 | 145 | 95 | 104 | 63 | 42 | 101 | 69 | 31 | 14 | 44 | 22 | 37 | 15 | 15 | 18 | 31 | 14 | 27 | 76 | 89 | 79 | 68 | 83 | 42 | 49 | 27 | 33 |
| 10:00 | 68 | 98 | 69 | 105 | 146 | 90 | 115 | 42 | 31 | 69 | 51 | 29 | 11 | 25 | 19 | 44 | 16 | 18 | 21 | 31 | 14 | 19 | 51 | 72 | 54 | 53 | 56 | 44 | 32 | 13 | 25 |
| 11:00 | 46 | 89 | 59 | 70 | 141 | 73 | 97 | 29 | 23 | 45 | 30 | 27 | 10 | 24 | 17 | 40 | 15 | 16 | 21 | 31 | 14 | 17 | 35 | 63 | 44 | 38 | 40 | 37 | 24 | 11 | 31 |
| 12:00 | 50 | 80 | 57 | 68 | 102 | 58 | 59 | 18 | 19 | 34 | 20 | 18 | 8 | 25 | 18 | 38 | 17 | 14 | 22 | 37 | 14 | 18 | 40 | 56 | 43 | 29 | 33 | 28 | 15 | 10 | 30 |
| 13:00 | 52 | 77 | 55 | 54 | 92 | 57 | 26 | 14 | 14 | 22 | 17 | 10 | 8 | 28 | 19 | 39 | 17 | 15 | 24 | 38 | 11 | 15 | 38 | 34 | 35 | 23 | 31 | 28 | 17 | 11 | 31 |
| 14:00 | 61 | 82 | 55 | 53 | 73 | 62 | 24 | 11 | 13 | 15 | 13 | 8 | 8 | 19 | 18 | 37 | 16 | 21 | 24 | 39 | 11 | 18 | 37 | 27 | 30 | 21 | 34 | 26 | 19 | 12 | 23 |
| 15:00 | 66 | 75 | 51 | 53 | 67 | 57 | 27 | 10 | 13 | 15 | 13 | 7 | 10 | 16 | 20 | 38 | 19 | 24 | 25 | 37 | 12 | 16 | 37 | 18 | 30 | 20 | 25 | 29 | 26 | 10 | 14 |
| 16:00 | 68 | 61 | 47 | 57 | 59 | 56 | 35 | 14 | 12 | 18 | 12 | 6 | 11 | 22 | 19 | 33 | 16 | 16 | 25 | 27 | 12 | 15 | 38 | 17 | 33 | 26 | 20 | 29 | 26 | 9 | 6 |
| 17:00 | 66 | 53 | 42 | 56 | 66 | 53 | 43 | 21 | 12 | 24 | 11 | 6 | 12 | 26 | 23 | 32 | 19 | 20 | 25 | 31 | 13 | 17 | 41 | 20 | 29 | 31 | 22 | 31 | 29 | 14 | 7 |
| 18:00 | 58 | 53 | 51 | 66 | 79 | 45 | 46 | 25 | 18 | 27 | 13 | 7 | 15 | 30 | 26 | 11 | 18 | 19 | 28 | 25 | 14 | 19 | 40 | 22 | 31 | 40 | 25 | 41 | 32 | 20 | 7 |
| 19:00 | 61 | 52 | 67 | 86 | 69 | 43 | 54 | 36 | 32 | 36 | 18 | 10 | 17 | 30 | 36 | 14 | 19 | 17 | 33 | 29 | 20 | 25 | 51 | 31 | 27 | 44 | 27 | 40 | 40 | 23 | 9 |
| 20:00 | 75 | 49 | 108 | 90 | 73 | 45 | 56 | 44 | 54 | 52 | 26 | 13 | 27 | 33 | 41 | 15 | 17 | 19 | 35 | 42 | 25 | 50 | 63 | 42 | 28 | 52 | 28 | 53 | 49 | 32 | 11 |
| 21:00 | 75 | 57 | 126 | 106 | 77 | 61 | 61 | 68 | 68 | 65 | 29 | 15 | 33 | 34 | 39 | 15 | 15 | 17 | 34 | 53 | 39 | 53 | 87 | 58 | 38 | 66 | 26 | 43 | 70 | 45 | 18 |
| 22:00 | 75 | 56 | 158 | 118 | 95 | 81 | 66 | 87 | 79 | 70 | 36 | 13 | 48 | 39 | 35 | 16 | 15 | 16 | 34 | 60 | 54 | 85 | 91 | 59 | 39 | 79 | 26 | 42 | 75 | 42 | 27 |
| 23:00 | 73 | 58 | 174 | 121 | 103 | 102 | 66 | 82 | 86 | 77 | 38 | 14 | 54 | 49 | 39 | 15 | 18 | 17 | 31 | 62 | 66 | 106 | 96 | 65 | 47 | 83 | 22 | 54 | 75 | 36 | 34 |
| 24:00 | 71 | 57 | 185 | 138 | 105 | 108 | 66 | 91 | 101 | 90 | 33 | 15 | 57 | 51 | 37 | 13 | 18 | 17 | 31 | 63 | 69 | 104 | 97 | 75 | 52 | 87 | 20 | 56 | 68 | 38 | 28 |
Colors refer to the following air quality index (AQI) codes: dark green—very good; green—good; yellow—moderate; orange—average; red—bad; maroon—very bad.
Table 2.
Daily and hourly PM10 content changes, with the hourly Polish AQI, average values for Kraków, March 2018 [39] (weekend marking in grey).
| PM10 | |||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Day | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 |
| Hour | |||||||||||||||||||||||||||||||
| 01:00 | 79 | 94 | 74 | 213 | 188 | 133 | 125 | 83 | 118 | 125 | 147 | 48 | 18 | 70 | 57 | 60 | 17 | 31 | 24 | 41 | 81 | 85 | 148 | 130 | 109 | 73 | 110 | 32 | 64 | 71 | 46 |
| 02:00 | 88 | 100 | 73 | 215 | 182 | 127 | 120 | 82 | 116 | 126 | 137 | 58 | 16 | 72 | 58 | 52 | 15 | 28 | 24 | 41 | 83 | 75 | 145 | 124 | 109 | 73 | 109 | 29 | 66 | 65 | 38 |
| 03:00 | 110 | 103 | 76 | 213 | 181 | 135 | 121 | 81 | 112 | 120 | 125 | 42 | 8 | 68 | 59 | 48 | 15 | 27 | 23 | 38 | 89 | 66 | 147 | 125 | 108 | 74 | 107 | 30 | 58 | 62 | 39 |
| 04:00 | 119 | 108 | 76 | 216 | 169 | 136 | 110 | 77 | 100 | 112 | 115 | 32 | 12 | 70 | 52 | 52 | 16 | 25 | 24 | 36 | 99 | 61 | 141 | 124 | 114 | 76 | 98 | 33 | 58 | 53 | 38 |
| 05:00 | 121 | 109 | 89 | 213 | 164 | 128 | 112 | 75 | 94 | 112 | 110 | 28 | 9 | 67 | 42 | 52 | 15 | 23 | 22 | 41 | 104 | 58 | 139 | 129 | 119 | 87 | 95 | 36 | 52 | 51 | 36 |
| 06:00 | 130 | 110 | 93 | 198 | 157 | 122 | 113 | 81 | 100 | 113 | 110 | 24 | 13 | 66 | 38 | 48 | 15 | 23 | 21 | 46 | 91 | 60 | 129 | 126 | 119 | 92 | 90 | 45 | 48 | 56 | 35 |
| 07:00 | 146 | 115 | 103 | 195 | 172 | 118 | 100 | 84 | 95 | 115 | 104 | 28 | 19 | 75 | 34 | 46 | 19 | 28 | 22 | 55 | 46 | 68 | 129 | 139 | 115 | 100 | 99 | 53 | 52 | 62 | 35 |
| 08:00 | 170 | 116 | 106 | 184 | 178 | 116 | 112 | 84 | 88 | 118 | 101 | 38 | 31 | 70 | 30 | 46 | 20 | 30 | 23 | 49 | 17 | 69 | 123 | 127 | 111 | 116 | 107 | 59 | 55 | 51 | 41 |
| 09:00 | 143 | 130 | 102 | 161 | 177 | 123 | 130 | 70 | 43 | 121 | 86 | 68 | 30 | 71 | 27 | 45 | 21 | 31 | 27 | 40 | 19 | 67 | 130 | 121 | 96 | 109 | 104 | 60 | 65 | 46 | 43 |
| 10:00 | 86 | 118 | 90 | 128 | 207 | 126 | 140 | 54 | 32 | 117 | 74 | 71 | 30 | 39 | 25 | 49 | 20 | 36 | 29 | 42 | 29 | 52 | 82 | 99 | 73 | 98 | 79 | 67 | 47 | 34 | 31 |
| 11:00 | 56 | 120 | 83 | 98 | 214 | 106 | 129 | 48 | 26 | 72 | 50 | 71 | 33 | 35 | 27 | 51 | 21 | 35 | 26 | 42 | 37 | 35 | 58 | 78 | 59 | 60 | 45 | 59 | 34 | 26 | 41 |
| 12:00 | 64 | 112 | 79 | 102 | 171 | 80 | 105 | 35 | 38 | 61 | 36 | 51 | 25 | 35 | 34 | 51 | 22 | 33 | 31 | 56 | 35 | 33 | 58 | 69 | 56 | 52 | 43 | 52 | 19 | 25 | 36 |
| 13:00 | 84 | 112 | 74 | 85 | 143 | 81 | 57 | 31 | 35 | 44 | 30 | 40 | 27 | 34 | 40 | 50 | 23 | 33 | 31 | 63 | 28 | 33 | 59 | 48 | 52 | 45 | 41 | 47 | 24 | 20 | 42 |
| 14:00 | 94 | 119 | 77 | 83 | 121 | 82 | 49 | 27 | 32 | 34 | 29 | 42 | 27 | 26 | 37 | 43 | 24 | 39 | 30 | 49 | 25 | 30 | 58 | 40 | 45 | 39 | 42 | 43 | 26 | 20 | 40 |
| 15:00 | 101 | 106 | 69 | 81 | 110 | 72 | 49 | 26 | 32 | 36 | 23 | 29 | 27 | 20 | 38 | 44 | 27 | 36 | 31 | 55 | 29 | 32 | 59 | 33 | 43 | 36 | 33 | 48 | 38 | 21 | 33 |
| 16:00 | 101 | 93 | 68 | 84 | 98 | 70 | 53 | 30 | 28 | 42 | 25 | 34 | 34 | 29 | 37 | 40 | 26 | 30 | 39 | 36 | 25 | 29 | 62 | 29 | 46 | 44 | 26 | 48 | 48 | 25 | 24 |
| 17:00 | 95 | 84 | 59 | 88 | 108 | 71 | 59 | 34 | 29 | 48 | 24 | 27 | 32 | 33 | 38 | 36 | 25 | 33 | 37 | 39 | 33 | 31 | 61 | 31 | 49 | 54 | 29 | 50 | 55 | 29 | 25 |
| 18:00 | 101 | 82 | 84 | 109 | 123 | 54 | 65 | 43 | 38 | 55 | 36 | 20 | 39 | 36 | 47 | 17 | 24 | 29 | 37 | 35 | 30 | 48 | 64 | 36 | 61 | 64 | 42 | 60 | 64 | 32 | 19 |
| 19:00 | 107 | 81 | 108 | 135 | 108 | 55 | 73 | 57 | 62 | 69 | 44 | 27 | 39 | 37 | 60 | 16 | 23 | 28 | 43 | 35 | 41 | 93 | 81 | 49 | 51 | 72 | 52 | 62 | 78 | 35 | 18 |
| 20:00 | 112 | 70 | 143 | 152 | 113 | 63 | 77 | 66 | 98 | 92 | 73 | 27 | 51 | 41 | 57 | 18 | 22 | 29 | 48 | 47 | 56 | 148 | 101 | 59 | 43 | 83 | 46 | 62 | 94 | 39 | 18 |
| 21:00 | 104 | 77 | 173 | 168 | 118 | 77 | 78 | 101 | 116 | 137 | 91 | 32 | 60 | 41 | 58 | 19 | 28 | 31 | 48 | 60 | 78 | 151 | 116 | 71 | 55 | 90 | 38 | 56 | 101 | 49 | 32 |
| 22:00 | 93 | 71 | 199 | 165 | 136 | 95 | 74 | 115 | 117 | 142 | 83 | 32 | 77 | 43 | 46 | 21 | 23 | 26 | 51 | 68 | 87 | 163 | 123 | 85 | 66 | 105 | 33 | 55 | 105 | 51 | 30 |
| 23:00 | 97 | 75 | 199 | 175 | 133 | 109 | 75 | 118 | 135 | 136 | 65 | 37 | 81 | 50 | 46 | 21 | 26 | 28 | 47 | 74 | 93 | 156 | 132 | 89 | 62 | 100 | 28 | 65 | 91 | 50 | 36 |
| 24:00 | 98 | 77 | 204 | 186 | 131 | 116 | 76 | 118 | 139 | 145 | 54 | 30 | 79 | 53 | 51 | 16 | 33 | 30 | 41 | 76 | 90 | 149 | 138 | 103 | 68 | 122 | 28 | 64 | 76 | 48 | 35 |
Colors refer to the following air quality index (AQI) codes: dark green—very good; green—good; yellow—moderate; orange—average; red—bad; maroon—very bad.
Table 3.
Daily and hourly C6H6 content changes, with the hourly Polish AQI, average values for Kraków, March 2018 [39] (weekend marking in grey).
| C6H6 | |||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Day | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 |
| Hour | |||||||||||||||||||||||||||||||
| 01:00 | 5.6 | 5.5 | 3.2 | 11.4 | 11.4 | 9.1 | 10.3 | 5.1 | 8.8 | 10.2 | 9.6 | 5.7 | 0.7 | 4.4 | 3.4 | 4.6 | 1.0 | 0.8 | 0.8 | 1.6 | 4.5 | 4.8 | 11.2 | 8.2 | 5.5 | 3.9 | 4.7 | 1.1 | 5.0 | 4.8 | 4.7 |
| 02:00 | 6.1 | 5.8 | 3.2 | 14.9 | 11.7 | 10.0 | 10.3 | 5.1 | 9.6 | 9.9 | 9.3 | 4.1 | 0.5 | 4.2 | 3.5 | 3.7 | 0.9 | 0.7 | 0.8 | 1.8 | 4.7 | 4.2 | 11.8 | 8.0 | 5.7 | 3.9 | 4.7 | 1.1 | 3.5 | 5.5 | 5.5 |
| 03:00 | 7.4 | 6.0 | 3.3 | 12.3 | 10.9 | 11.0 | 9.4 | 4.8 | 8.9 | 9.1 | 9.3 | 2.9 | 0.4 | 4.3 | 3.9 | 3.8 | 0.8 | 0.6 | 0.8 | 1.7 | 4.8 | 3.7 | 12.3 | 8.3 | 5.8 | 3.9 | 4.7 | 1.1 | 3.8 | 4.3 | 5.8 |
| 04:00 | 8.2 | 6.7 | 3.4 | 12.4 | 12.2 | 10.9 | 11.0 | 4.9 | 9.1 | 9.0 | 8.9 | 1.7 | 0.4 | 3.9 | 3.0 | 3.7 | 0.7 | 0.6 | 0.8 | 1.6 | 5.0 | 3.2 | 11.8 | 8.4 | 6.4 | 3.9 | 4.1 | 1.3 | 2.5 | 2.7 | 5.3 |
| 05:00 | 8.1 | 6.7 | 3.6 | 11.3 | 11.5 | 10.1 | 11.6 | 5.2 | 8.0 | 9.0 | 8.9 | 1.2 | 0.6 | 3.8 | 2.3 | 3.3 | 0.6 | 0.6 | 0.8 | 1.6 | 5.4 | 2.9 | 10.6 | 9.1 | 7.4 | 4.2 | 4.2 | 1.7 | 2.7 | 2.9 | 5.0 |
| 06:00 | 8.0 | 6.9 | 3.9 | 10.4 | 9.6 | 9.2 | 12.4 | 5.3 | 8.3 | 9.0 | 8.7 | 1.1 | 1.1 | 3.6 | 1.9 | 2.6 | 0.6 | 0.6 | 1.0 | 1.9 | 4.8 | 2.9 | 10.2 | 7.6 | 7.0 | 4.7 | 4.5 | 2.4 | 2.1 | 4.1 | 3.5 |
| 07:00 | 9.5 | 6.5 | 4.6 | 9.6 | 10.2 | 8.6 | 11.7 | 6.6 | 8.4 | 9.3 | 8.4 | 1.6 | 1.8 | 3.9 | 2.0 | 2.5 | 0.7 | 0.6 | 1.1 | 2.5 | 3.5 | 3.1 | 9.3 | 7.6 | 7.2 | 5.6 | 5.1 | 3.3 | 1.7 | 3.9 | 4.4 |
| 08:00 | 11.6 | 6.5 | 5.1 | 9.2 | 12.1 | 7.6 | 12.7 | 6.2 | 7.3 | 9.5 | 7.9 | 1.8 | 2.2 | 3.9 | 2.1 | 3.5 | 0.8 | 0.6 | 1.1 | 2.4 | 2.0 | 2.6 | 8.2 | 6.8 | 6.1 | 5.2 | 5.2 | 2.5 | 3.2 | 2.6 | 6.2 |
| 09:00 | 8.6 | 7.3 | 5.3 | 6.8 | 18.9 | 8.0 | 12.9 | 4.7 | 3.6 | 8.6 | 5.2 | 2.6 | 1.3 | 3.0 | 2.1 | 3.9 | 0.9 | 0.7 | 1.2 | 2.2 | 0.9 | 2.1 | 5.7 | 7.7 | 4.2 | 4.4 | 4.9 | 2.1 | 4.2 | 1.4 | 4.0 |
| 10:00 | 4.5 | 5.8 | 3.7 | 5.4 | 12.4 | 7.5 | 11.3 | 2.6 | 2.5 | 5.6 | 3.7 | 1.6 | 0.9 | 2.1 | 1.8 | 3.7 | 0.9 | 0.7 | 1.4 | 2.1 | 0.7 | 1.3 | 3.2 | 3.5 | 3.1 | 3.2 | 3.7 | 2.4 | 3.1 | 0.8 | 3.2 |
| 11:00 | 3.2 | 4.9 | 3.1 | 4.0 | 9.9 | 5.3 | 8.0 | 1.9 | 1.6 | 3.1 | 2.4 | 1.5 | 0.7 | 1.5 | 2.0 | 3.7 | 1.0 | 0.7 | 1.3 | 2.0 | 0.7 | 0.9 | 2.1 | 3.4 | 2.6 | 2.9 | 2.7 | 1.8 | 1.5 | 0.7 | 3.0 |
| 12:00 | 2.8 | 4.5 | 2.9 | 2.9 | 7.9 | 4.3 | 3.2 | 1.3 | 1.1 | 2.5 | 1.5 | 0.8 | 0.6 | 1.9 | 1.9 | 3.8 | 1.0 | 0.8 | 1.3 | 2.1 | 0.7 | 0.8 | 1.7 | 3.2 | 2.5 | 2.2 | 2.6 | 1.3 | 1.2 | 0.7 | 4.0 |
| 13:00 | 2.9 | 4.5 | 2.8 | 2.7 | 8.0 | 4.2 | 1.7 | 1.1 | 0.8 | 1.9 | 1.2 | 0.5 | 0.7 | 1.9 | 1.7 | 3.8 | 0.8 | 0.8 | 1.4 | 2.3 | 0.7 | 0.8 | 1.9 | 2.2 | 2.1 | 1.6 | 2.1 | 1.1 | 1.1 | 0.7 | 2.1 |
| 14:00 | 2.8 | 4.3 | 3.0 | 2.6 | 7.8 | 4.5 | 1.9 | 1.1 | 0.9 | 1.2 | 1.2 | 0.5 | 0.6 | 1.5 | 1.4 | 3.6 | 1.0 | 0.9 | 1.4 | 2.4 | 0.7 | 0.9 | 1.8 | 1.7 | 1.9 | 1.5 | 1.5 | 1.2 | 1.2 | 0.8 | 1.9 |
| 15:00 | 3.1 | 4.3 | 2.5 | 2.4 | 5.0 | 4.9 | 2.1 | 1.2 | 0.9 | 1.4 | 1.2 | 0.5 | 0.8 | 1.6 | 1.6 | 4.3 | 1.0 | 1.3 | 1.6 | 2.0 | 0.9 | 0.9 | 1.9 | 1.3 | 2.0 | 1.6 | 1.4 | 1.3 | 1.3 | 0.8 | 0.8 |
| 16:00 | 3.1 | 3.4 | 2.5 | 9.2 | 4.4 | 8.2 | 2.3 | 1.7 | 0.8 | 1.7 | 1.0 | 0.6 | 1.0 | 2.4 | 1.5 | 3.0 | 1.0 | 1.0 | 1.9 | 2.2 | 0.9 | 1.0 | 1.9 | 1.3 | 1.9 | 1.9 | 1.5 | 1.4 | 1.3 | 0.8 | 0.7 |
| 17:00 | 3.1 | 3.2 | 2.6 | 3.3 | 9.1 | 5.5 | 2.7 | 1.8 | 1.1 | 5.1 | 1.0 | 0.9 | 1.2 | 2.6 | 1.5 | 2.7 | 1.0 | 0.9 | 2.0 | 2.4 | 1.0 | 1.2 | 2.1 | 1.4 | 1.9 | 2.3 | 1.5 | 3.7 | 2.2 | 1.1 | 1.0 |
| 18:00 | 3.1 | 3.4 | 2.9 | 3.3 | 7.8 | 5.7 | 3.1 | 2.1 | 1.5 | 3.9 | 1.7 | 1.0 | 1.2 | 2.6 | 2.2 | 2.5 | 1.1 | 1.0 | 2.1 | 2.3 | 1.1 | 1.5 | 2.3 | 1.9 | 2.2 | 2.7 | 1.6 | 3.5 | 2.0 | 1.3 | 1.2 |
| 19:00 | 3.6 | 3.3 | 4.2 | 3.9 | 6.9 | 5.2 | 4.2 | 2.5 | 2.6 | 3.4 | 2.4 | 1.1 | 1.8 | 2.6 | 4.5 | 2.1 | 1.2 | 1.1 | 2.0 | 2.5 | 1.8 | 3.1 | 3.2 | 3.4 | 2.3 | 3.4 | 2.0 | 3.2 | 2.9 | 3.1 | 1.4 |
| 20:00 | 4.7 | 3.4 | 7.4 | 5.9 | 7.4 | 5.5 | 4.9 | 3.5 | 4.7 | 5.1 | 3.3 | 1.4 | 2.3 | 2.5 | 4.7 | 1.9 | 1.0 | 1.1 | 1.7 | 3.1 | 2.1 | 5.2 | 4.2 | 4.6 | 2.3 | 4.1 | 1.9 | 3.1 | 4.6 | 2.9 | 2.5 |
| 21:00 | 5.7 | 3.5 | 10.3 | 10.6 | 7.2 | 6.6 | 5.5 | 4.9 | 5.7 | 6.5 | 3.8 | 1.3 | 2.8 | 2.6 | 3.7 | 1.7 | 1.0 | 1.0 | 1.9 | 4.1 | 3.1 | 6.9 | 4.4 | 4.6 | 2.9 | 4.7 | 1.6 | 3.3 | 6.5 | 3.3 | 2.5 |
| 22:00 | 5.6 | 3.5 | 12.9 | 14.3 | 7.5 | 8.4 | 5.5 | 6.7 | 7.4 | 7.1 | 4.3 | 1.3 | 4.0 | 2.9 | 3.0 | 1.7 | 1.0 | 1.1 | 1.7 | 4.4 | 4.2 | 9.4 | 6.3 | 6.0 | 3.2 | 5.2 | 1.3 | 4.4 | 6.9 | 3.4 | 3.1 |
| 23:00 | 5.0 | 3.6 | 13.2 | 8.3 | 8.4 | 9.2 | 5.1 | 7.2 | 7.9 | 9.1 | 3.7 | 1.3 | 4.6 | 3.6 | 3.5 | 1.4 | 0.9 | 0.9 | 1.7 | 4.3 | 4.8 | 11.3 | 6.9 | 4.4 | 3.4 | 5.0 | 1.0 | 3.7 | 6.1 | 4.7 | 3.7 |
| 24:00 | 4.7 | 3.5 | 14.1 | 9.8 | 8.8 | 9.9 | 5.1 | 8.8 | 8.3 | 9.7 | 2.8 | 1.2 | 4.4 | 3.3 | 3.8 | 1.3 | 0.9 | 0.9 | 1.7 | 4.4 | 5.3 | 11.5 | 7.1 | 5.1 | 3.6 | 5.0 | 1.1 | 3.5 | 4.9 | 4.9 | 3.0 |
Colors refer to the following air quality index (AQI) codes: dark green—very good; green—good; yellow—moderate; orange—average; red—bad; maroon—very bad.
Table 4.
Daily and hourly NO2 content changes, with the hourly Polish AQI, average values for Kraków, March 2018 [39] (weekend marking in grey).
| NO2 | |||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Day | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 |
| Hour | |||||||||||||||||||||||||||||||
| 01:00 | 44 | 30 | 27 | 80 | 80 | 82 | 59 | 57 | 61 | 67 | 59 | 26 | 22 | 55 | 36 | 29 | 14 | 11 | 10 | 16 | 41 | 44 | 70 | 63 | 71 | 51 | 49 | 23 | 32 | 46 | 31 |
| 02:00 | 54 | 32 | 29 | 75 | 72 | 75 | 62 | 53 | 53 | 64 | 55 | 26 | 24 | 49 | 36 | 26 | 12 | 10 | 10 | 16 | 42 | 36 | 60 | 55 | 63 | 53 | 43 | 22 | 34 | 45 | 23 |
| 03:00 | 58 | 30 | 30 | 70 | 62 | 74 | 59 | 47 | 44 | 55 | 52 | 21 | 18 | 44 | 35 | 24 | 11 | 9 | 9 | 15 | 41 | 36 | 53 | 53 | 56 | 49 | 41 | 27 | 28 | 47 | 29 |
| 04:00 | 56 | 32 | 27 | 64 | 56 | 72 | 56 | 43 | 40 | 49 | 45 | 18 | 25 | 42 | 33 | 25 | 9 | 8 | 12 | 19 | 46 | 38 | 51 | 46 | 54 | 51 | 41 | 34 | 33 | 41 | 29 |
| 05:00 | 55 | 34 | 46 | 62 | 61 | 72 | 61 | 40 | 42 | 46 | 37 | 18 | 32 | 45 | 27 | 25 | 9 | 9 | 12 | 20 | 49 | 44 | 47 | 45 | 50 | 57 | 51 | 51 | 35 | 47 | 33 |
| 06:00 | 60 | 40 | 57 | 60 | 66 | 74 | 63 | 47 | 47 | 46 | 36 | 36 | 49 | 48 | 26 | 28 | 10 | 7 | 18 | 38 | 56 | 58 | 53 | 58 | 49 | 64 | 65 | 61 | 55 | 58 | 35 |
| 07:00 | 71 | 50 | 67 | 58 | 83 | 81 | 67 | 63 | 56 | 47 | 36 | 52 | 72 | 58 | 36 | 30 | 13 | 9 | 28 | 47 | 52 | 70 | 63 | 63 | 46 | 64 | 73 | 65 | 67 | 61 | 37 |
| 08:00 | 79 | 53 | 64 | 56 | 93 | 76 | 71 | 76 | 64 | 56 | 40 | 66 | 73 | 63 | 31 | 31 | 16 | 10 | 30 | 44 | 42 | 68 | 68 | 55 | 51 | 74 | 65 | 58 | 72 | 56 | 38 |
| 09:00 | 69 | 52 | 58 | 55 | 104 | 62 | 79 | 73 | 71 | 64 | 45 | 70 | 51 | 64 | 26 | 31 | 20 | 11 | 31 | 49 | 33 | 58 | 74 | 51 | 46 | 78 | 59 | 53 | 80 | 45 | 41 |
| 10:00 | 46 | 43 | 42 | 51 | 104 | 55 | 86 | 57 | 58 | 55 | 36 | 53 | 37 | 49 | 34 | 32 | 22 | 11 | 35 | 43 | 27 | 43 | 63 | 51 | 34 | 70 | 50 | 45 | 67 | 34 | 30 |
| 11:00 | 31 | 38 | 35 | 38 | 85 | 52 | 83 | 37 | 43 | 43 | 37 | 50 | 31 | 41 | 31 | 34 | 21 | 13 | 32 | 38 | 26 | 28 | 41 | 42 | 29 | 49 | 47 | 36 | 56 | 27 | 32 |
| 12:00 | 32 | 37 | 35 | 38 | 75 | 52 | 64 | 32 | 28 | 42 | 28 | 42 | 26 | 41 | 32 | 35 | 23 | 12 | 32 | 47 | 26 | 28 | 41 | 42 | 31 | 45 | 48 | 31 | 36 | 27 | 32 |
| 13:00 | 33 | 39 | 34 | 35 | 71 | 53 | 38 | 30 | 27 | 38 | 27 | 22 | 26 | 43 | 38 | 41 | 21 | 14 | 33 | 46 | 27 | 31 | 39 | 36 | 30 | 48 | 49 | 31 | 35 | 26 | 32 |
| 14:00 | 37 | 46 | 36 | 31 | 66 | 60 | 36 | 32 | 27 | 33 | 29 | 25 | 32 | 36 | 40 | 43 | 22 | 14 | 32 | 46 | 26 | 33 | 43 | 34 | 28 | 48 | 42 | 34 | 37 | 27 | 29 |
| 15:00 | 46 | 48 | 33 | 36 | 67 | 74 | 40 | 35 | 28 | 36 | 27 | 31 | 34 | 34 | 31 | 48 | 19 | 18 | 36 | 42 | 32 | 36 | 46 | 30 | 32 | 43 | 38 | 39 | 38 | 31 | 29 |
| 16:00 | 45 | 45 | 37 | 43 | 68 | 80 | 49 | 39 | 35 | 44 | 32 | 41 | 42 | 46 | 32 | 53 | 20 | 17 | 39 | 43 | 30 | 40 | 50 | 29 | 33 | 48 | 38 | 36 | 45 | 34 | 26 |
| 17:00 | 45 | 43 | 34 | 47 | 79 | 74 | 50 | 48 | 36 | 50 | 29 | 40 | 47 | 47 | 36 | 54 | 19 | 17 | 37 | 53 | 38 | 44 | 45 | 32 | 42 | 62 | 40 | 38 | 52 | 34 | 31 |
| 18:00 | 49 | 47 | 54 | 57 | 104 | 75 | 61 | 56 | 57 | 49 | 43 | 42 | 52 | 46 | 40 | 33 | 21 | 18 | 42 | 58 | 40 | 74 | 51 | 38 | 57 | 67 | 47 | 48 | 66 | 39 | 47 |
| 19:00 | 52 | 45 | 88 | 75 | 83 | 77 | 69 | 69 | 79 | 66 | 57 | 40 | 55 | 49 | 45 | 27 | 19 | 18 | 36 | 70 | 53 | 96 | 55 | 44 | 68 | 70 | 51 | 45 | 74 | 40 | 41 |
| 20:00 | 53 | 35 | 110 | 77 | 83 | 79 | 69 | 73 | 100 | 81 | 85 | 44 | 62 | 50 | 47 | 24 | 20 | 20 | 35 | 81 | 65 | 113 | 60 | 48 | 66 | 71 | 39 | 42 | 78 | 62 | 36 |
| 21:00 | 48 | 33 | 111 | 77 | 95 | 86 | 66 | 87 | 94 | 90 | 81 | 48 | 65 | 48 | 41 | 21 | 17 | 21 | 31 | 68 | 85 | 116 | 72 | 52 | 75 | 66 | 32 | 34 | 73 | 70 | 31 |
| 22:00 | 47 | 33 | 98 | 84 | 105 | 77 | 64 | 88 | 93 | 84 | 75 | 39 | 71 | 47 | 30 | 21 | 16 | 16 | 30 | 57 | 84 | 99 | 77 | 60 | 62 | 61 | 26 | 36 | 71 | 67 | 40 |
| 23:00 | 44 | 33 | 87 | 81 | 98 | 62 | 61 | 82 | 83 | 76 | 56 | 46 | 70 | 45 | 28 | 22 | 13 | 15 | 25 | 61 | 72 | 86 | 74 | 59 | 59 | 53 | 22 | 42 | 61 | 49 | 45 |
| 24:00 | 36 | 31 | 82 | 84 | 91 | 58 | 58 | 69 | 81 | 70 | 35 | 45 | 61 | 41 | 28 | 17 | 12 | 13 | 20 | 49 | 60 | 75 | 68 | 70 | 57 | 49 | 22 | 35 | 46 | 36 | 40 |
Colors refer to the following air quality index (AQI) codes: dark green—very good; green—good; yellow—moderate; orange—average; red—bad; maroon—very bad.
Table 5.
Daily and hourly O3 content changes, with the hourly Polish AQI, average values for Kraków, March 2018 [39] (weekend marking in grey).
| O3 | |||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Day | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 |
| Hour | |||||||||||||||||||||||||||||||
| 01:00 | 14 | 44 | 75 | 5 | 6 | 3 | 3 | 4 | 2 | 4 | 4 | 56 | 66 | 4 | 6 | 20 | 67 | 80 | 86 | 70 | 42 | 21 | 5 | 5 | 3 | 3 | 8 | 35 | 35 | 3 | 38 |
| 02:00 | 4 | 43 | 75 | 4 | 19 | 3 | 2 | 12 | 3 | 4 | 2 | 49 | 68 | 5 | 5 | 18 | 71 | 83 | 85 | 71 | 32 | 12 | 5 | 5 | 4 | 3 | 12 | 31 | 36 | 3 | 39 |
| 03:00 | 3 | 41 | 69 | 5 | 40 | 2 | 3 | 5 | 3 | 3 | 3 | 48 | 69 | 3 | 6 | 16 | 74 | 84 | 86 | 71 | 30 | 23 | 4 | 4 | 3 | 2 | 8 | 21 | 36 | 14 | 37 |
| 04:00 | 3 | 39 | 67 | 6 | 42 | 3 | 2 | 9 | 4 | 4 | 3 | 51 | 62 | 3 | 5 | 13 | 73 | 82 | 84 | 59 | 18 | 21 | 5 | 4 | 2 | 2 | 15 | 21 | 30 | 23 | 37 |
| 05:00 | 4 | 37 | 8 | 3 | 37 | 3 | 3 | 6 | 6 | 4 | 3 | 65 | 43 | 3 | 21 | 15 | 66 | 80 | 85 | 57 | 12 | 10 | 5 | 3 | 5 | 3 | 24 | 11 | 25 | 6 | 37 |
| 06:00 | 3 | 34 | 3 | 4 | 33 | 3 | 2 | 1 | 3 | 3 | 4 | 63 | 44 | 3 | 27 | 9 | 72 | 79 | 82 | 44 | 8 | 5 | 5 | 2 | 7 | 3 | 8 | 3 | 8 | 2 | 34 |
| 07:00 | 4 | 28 | 4 | 4 | 12 | 2 | 3 | 3 | 3 | 4 | 3 | 51 | 6 | 3 | 20 | 8 | 72 | 79 | 78 | 37 | 11 | 8 | 4 | 2 | 4 | 4 | 4 | 7 | 5 | 3 | 32 |
| 08:00 | 5 | 27 | 6 | 4 | 5 | 4 | 3 | 3 | 4 | 3 | 8 | 50 | 15 | 3 | 16 | 9 | 70 | 79 | 72 | 31 | 43 | 19 | 11 | 27 | 11 | 5 | 2 | 23 | 6 | 15 | 34 |
| 09:00 | 9 | 29 | 26 | 32 | 8 | 11 | 3 | 10 | 9 | 5 | 23 | 40 | 33 | 8 | 18 | 10 | 69 | 77 | 75 | 38 | 66 | 53 | 17 | 61 | 38 | 16 | 6 | 25 | 3 | 46 | 27 |
| 10:00 | 34 | 43 | 62 | 52 | 16 | 30 | 5 | 30 | 28 | 15 | 35 | 52 | 50 | 27 | 21 | 14 | 70 | 78 | 78 | 59 | 77 | 75 | 37 | 77 | 62 | 27 | 7 | 29 | 32 | 70 | 28 |
| 11:00 | 57 | 59 | 73 | 63 | 37 | 46 | 27 | 53 | 60 | 32 | 54 | 61 | 61 | 30 | 38 | 16 | 69 | 79 | 80 | 64 | 82 | 78 | 63 | 79 | 74 | 61 | 10 | 61 | 47 | 78 | 27 |
| 12:00 | 64 | 72 | 77 | 71 | 54 | 59 | 60 | 66 | 71 | 49 | 76 | 63 | 69 | 31 | 53 | 17 | 71 | 82 | 81 | 65 | 83 | 78 | 64 | 83 | 83 | 80 | 13 | 67 | 61 | 88 | 32 |
| 13:00 | 73 | 81 | 86 | 86 | 74 | 61 | 68 | 69 | 77 | 64 | 84 | 77 | 71 | 21 | 50 | 18 | 72 | 82 | 84 | 62 | 84 | 80 | 65 | 95 | 99 | 75 | 20 | 70 | 58 | 91 | 41 |
| 14:00 | 77 | 87 | 88 | 90 | 92 | 58 | 71 | 67 | 81 | 78 | 89 | 76 | 73 | 14 | 43 | 18 | 77 | 85 | 84 | 56 | 82 | 86 | 66 | 93 | 104 | 75 | 32 | 74 | 31 | 91 | 56 |
| 15:00 | 65 | 91 | 96 | 96 | 93 | 54 | 65 | 65 | 81 | 79 | 91 | 77 | 67 | 13 | 41 | 20 | 78 | 83 | 84 | 67 | 78 | 83 | 59 | 95 | 107 | 77 | 33 | 77 | 37 | 93 | 75 |
| 16:00 | 66 | 90 | 96 | 95 | 91 | 45 | 50 | 59 | 76 | 80 | 91 | 71 | 59 | 13 | 39 | 21 | 77 | 86 | 84 | 66 | 78 | 78 | 56 | 98 | 107 | 69 | 38 | 76 | 40 | 94 | 78 |
| 17:00 | 64 | 89 | 96 | 98 | 64 | 30 | 47 | 52 | 68 | 71 | 86 | 64 | 55 | 7 | 32 | 10 | 80 | 85 | 83 | 55 | 75 | 73 | 62 | 96 | 98 | 57 | 36 | 74 | 34 | 87 | 74 |
| 18:00 | 62 | 84 | 85 | 79 | 21 | 15 | 25 | 35 | 43 | 69 | 72 | 60 | 44 | 7 | 22 | 12 | 80 | 84 | 80 | 59 | 67 | 48 | 59 | 93 | 70 | 44 | 39 | 67 | 16 | 79 | 59 |
| 19:00 | 53 | 81 | 47 | 70 | 46 | 11 | 13 | 18 | 10 | 49 | 68 | 55 | 37 | 8 | 8 | 21 | 76 | 84 | 79 | 46 | 46 | 8 | 44 | 83 | 60 | 35 | 26 | 57 | 4 | 74 | 59 |
| 20:00 | 46 | 86 | 5 | 68 | 46 | 5 | 22 | 11 | 4 | 13 | 30 | 57 | 19 | 5 | 6 | 31 | 77 | 85 | 80 | 28 | 32 | 6 | 34 | 66 | 30 | 28 | 28 | 55 | 4 | 51 | 59 |
| 21:00 | 46 | 80 | 5 | 58 | 41 | 2 | 24 | 3 | 3 | 3 | 18 | 58 | 12 | 9 | 12 | 42 | 81 | 84 | 79 | 23 | 12 | 5 | 10 | 66 | 7 | 26 | 43 | 55 | 3 | 5 | 51 |
| 22:00 | 43 | 78 | 4 | 27 | 6 | 3 | 12 | 3 | 5 | 4 | 42 | 60 | 4 | 6 | 20 | 52 | 84 | 84 | 79 | 31 | 6 | 6 | 6 | 61 | 14 | 25 | 48 | 52 | 3 | 4 | 39 |
| 23:00 | 40 | 77 | 5 | 35 | 4 | 4 | 6 | 3 | 3 | 3 | 65 | 44 | 3 | 7 | 17 | 55 | 82 | 84 | 81 | 25 | 6 | 5 | 6 | 58 | 15 | 11 | 51 | 47 | 3 | 17 | 10 |
| 24:00 | 41 | 78 | 5 | 15 | 4 | 3 | 6 | 2 | 3 | 4 | 68 | 54 | 3 | 8 | 21 | 62 | 79 | 84 | 76 | 26 | 8 | 5 | 6 | 19 | 3 | 19 | 55 | 39 | 3 | 30 | 20 |
Colors refer to the following air quality index (AQI) codes: dark green—very good; green—good; yellow—moderate; orange—average; red—bad; maroon—very bad.
The decreases in the monthly contents recorded in the first five months of 2020 (Table S13) were observed for PM2.5, PM10, and C6H6, and slight decreases of monthly contents were also observed in the case of NO2.
3.2. PM Enrichment Factors
Based on the above conclusions, particulate matter was determined to be the most significant contaminant. Since PM particles adsorb various pollutants, our subsequent investigations focussed on heavy metal contents in deposited PM particles. The calculated values of the applied enrichment indices and of the corresponding classes are presented in Table 6. Enrichment factors calculated for average heavy metal content data and obtained from the Regional Environmental Protection Inspectorate (REPI) measurements revealed that suspended PM10, according to Igeo classification, remained practically uncontaminated (class 0) with Cd and Pb, moderately to heavily contaminated (class 3) with As, and extremely contaminated (class 6) with Ni. The CF index indicated a low contamination of PM10 with As, Ni, and Pb, although a very high contamination with Cd was identified. The EF values (calculated here as the mean values of EF established for various background values) indicated a moderately severe enrichment of PM10 with Cd, while in the cases of As, Ni, and Pb, no enrichment was found. The calculated values of ERI indicated high ecological risk in respect of Cd and low ecological risk in respect of As, Ni, and Pb. Ecological risk, defined on the basis of the mHQ index, revealed a very low severity of contamination with Cd and none to very low severity of contamination with As, Ni, and Pb.
Table 6.
Enrichment index classes for deposited PM in Kraków (modified after [49]). Igeo: geoaccumulation index, CF: contamination factor, EF: enrichment factor, ERI: ecological risk index, mHQ: modified hazard quotient.
| Element | Igeo | CF | EF (mean) | ERI | mHQ | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| Value | Class | Value | Class | Value | Class | Value | Class | Value | Class | |
| As | 5.6 | 6 | 3.06 | considerable | 2.63 | minor | 30.6 | low | 1.90 | moderate severity |
| As (PM10) | 2.1 | 3 | 0.27 | low | 0.23 | no | 2.7 | low | 0.17 | nil to very low |
| Ba | 15.5 | 6 | 0.18 | low | 0.15 | no | - | - | - | - |
| Be | −0.4 | 0 | 0.26 | low | 0.22 | no | - | - | - | - |
| Cd | −3.8 | 0 | 13.3 | very high | 11.44 | severe | 400 | very high | 1.24 | low severity |
| Cd (PM10) | −4.6 | 0 | 7.56 | very high | 6.49 | moderately severe | 227 | high | 0.70 | very low |
| Co | 4.8 | 5 | 0.14 | low | 0.12 | no | 0.7 | low | - | - |
| Cr | 12.4 | 6 | 0.98 | low | 0.84 | no | 2.0 | low | 2.12 | considerable severity |
| Cu | 10.4 | 6 | 2.66 | moderate | 2.28 | minor | 13.3 | low | 1.57 | moderate severity |
| Li | 8.2 | 6 | 1.00 | moderate | 0.86 | no | - | - | - | - |
| Mn | 18.3 | 6 | 0.81 | low | 0.69 | no | - | - | - | - |
| Ni | 9.6 | 6 | 0.52 | low | 0.45 | no | 2.6 | low | 1.18 | low severity |
| Ni (PM10) | 5.7 | 6 | 0.04 | low | 0.03 | no | 0.2 | low | 0.08 | nil to very low |
| Pb | 9.9 | 6 | 5.03 | considerable | 4.32 | moderate | 25.1 | low | 1.86 | moderate severity |
| Pb (PM10) | −1.3 | 0 | 0.002 | low | 0.002 | no | 0.01 | low | 0.001 | nil to very low |
| Sn | 4.1 | 5 | 5.95 | considerable | 5.11 | moderately severe | - | - | - | - |
| Sr | 14.9 | 6 | 0.44 | low | 0.38 | no | - | - | - | - |
| Ti | 19.6 | 6 | 0.04 | low | 0.03 | no | - | - | - | - |
| Tl | −2.7 | 0 | 0.29 | low | 0.25 | no | 2.9 | low | - | - |
| V | 10.9 | 6 | 0.31 | low | 0.27 | no | - | - | - | - |
| Zn | 18.0 | 6 | 86.87 | very high | 74.56 | extremely severe | 86.9 | considerable | 36.45 | extreme severity |
−: not applicable.
The results of the calculations of heavy metal contents in deposited PM were described in a conference paper by Gruszecka-Kosowska [49]. Based on the calculated Igeo values in deposited PM samples, heavy metal accumulation was found to be the highest for As, Ba, Cr, Cu, Li, Mn, Ni, Pb, Sr, Ti, V, and Zn (class 6), as well as Co and Sn (class 5). Instead, in the cases of Be, Cd, and Tl, the calculated Igeo values indicated no accumulation (class 0). On the other hand, the calculated CF values revealed a very high contamination of deposited PM samples with Cd and Zn, considerable contamination with As, Pb, and Sn, and moderate contamination with Cu and Li. As to the remaining investigated elements, the CF values indicated low contamination. Besides, the EF values indicated that deposited PM samples were extremely severely enriched with Zn, moderately to severely enriched with Sn, and severely enriched with Cd. A minor enrichment of PM with Cu was observed. As to the remaining investigated elements, the EF values indicated no enrichment. The calculated values of ERI indicated a very high ecological risk of deposited PM samples only in the case of Cd and considerable ecological risk in respect of Zn. Low ecological risk was determined in respect of As, Co, Cr, Cu, Ni, Pb, and Tl. Ecological risk, based on the mHQ index, revealed an extreme severity of contamination of deposited PM samples with Zn and a considerable severity of contamination with Cr. As to As, Cu, and Pb, moderate severity contamination was indicated, while in the cases of Cd and Ni, low-severity contamination was indicated. The values of mHQ were not defined for Ba, Be, Co, Li, Mn, Sn, Sr, Ti, Tl, and V due to the lack of adverse ecological effect values.
3.3. Health Risk Assessment
Since the Polish AQI index provides general health risk information focussed on resident actions from “stay at home” to “safe intense physical activity”, our risk assessment was calculated to define the reliable risk for inhabitants [58]. Health risk assessment of the investigated air pollutants was calculated on such a basis that if the RfC values for non-carcinogenic and the IUR values for carcinogenic pollutants were available, the relevant equations were used in the first place.
The calculated estimated daily intakes are presented in Table S14. For our calculations, the pollutant content mean values from the available monitoring stations and the last 15 years were used. The health risk assessment values for the residents of Kraków are presented in Table 7. The total non-carcinogenic risk, calculated as the sum of single non-carcinogenic pollutant rates, exceeded the acceptable level significantly. The risk rate was equal to 15.0 in adult residents and 26.4 in children. The total carcinogenic risk, which was calculated as the sum of single carcinogenic pollutant rates, exceeded the acceptable level as well. The risk rate was equal to 1.51 × 10−4 in adult residents and 1.77 × 10−4 in children.
Table 7.
Risk assessment values for the residents of Kraków.
| Pollutant | Inhalation | Ingestion | Dermal contact | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| HQ | CR | HQ | CR | HQ | CR | |||||||
| Adult | Child | Adult | Child | Adult | Child | Adult | Child | Adult | Child | Adult | Child | |
| Ambient Air | ||||||||||||
| NO2 | 1.13 × 100 | 2.64 × 100 | na | na | – | – | ||||||
| Benzen | 1.02 × 10−1 | 1.02 × 10−1 | 8.21 × 10−12 | 2.05 × 10−12 | ||||||||
| PM2.5 | 7.23 × 100 | 7.23 × 100 | na | na | ||||||||
| PM10 | 1.42 × 100 | 3.32 × 100 | na | na | ||||||||
| Pb (PM10) | 2.90 × 10−3 | 6.76 × 10−3 | 2.67 × 10−5 | 8.52 × 10−8 | ||||||||
| As (PM10) | 8.31 × 10−2 | 8.31 × 10−2 | 1.84 × 10−12 | 4.59 × 10−13 | ||||||||
| Cd (PM10) | 6.52 × 10−2 | 6.52 × 10−2 | 4.02 × 10−13 | 1.01 × 10−13 | ||||||||
| Ni (PM10) | 1.77 × 10−2 | 1.77 × 10−2 | 1.42 × 10−16 | 3.55 × 10−17 | ||||||||
| BaP (PM10) | 2.83 × 100 | 2.83 × 100 | 1.16 × 10−12 | 2.91 × 10−13 | ||||||||
| BaA (PM10) | na | na | 1.15 × 10−13 | 2.88 × 10−14 | ||||||||
| BbF (PM10) | na | na | 6.65 × 10−14 | 1.66 × 10−14 | ||||||||
| BjF (PM10) | na | na | 1.06 × 10−13 | 2.66 × 10−14 | ||||||||
| BkF (PM10) | na | na | 5.31 × 10−15 | 1.33 × 10−15 | ||||||||
| DBahA (PM10) | na | na | 1.72 × 10−13 | 4.29 × 10−14 | ||||||||
| Deposited PM | ||||||||||||
| Al | 2.15 × 10−2 | 2.15 × 10−2 | na | na | 8.70 × 10−3 | 8.12 × 10−2 | na | na | 3.67 × 10−2 | 1.93 × 10−1 | na | na |
| As | 1.65 × 10−2 | 1.65 × 10−2 | 1.88 × 10−18 | 4.52 × 10−19 | 3.96 × 10−2 | 3.51 × 10−1 | 6.11 × 10−6 | 1.35 × 10−5 | 8.47 × 10−3 | 4.44 × 10−2 | 1.31 × 10−6 | 1.71 × 10−6 |
| Ba | 3.77 × 10−3 | 3.77 × 10−3 | na | na | 7.42 × 10−4 | 6.29 × 10−3 | na | na | 3.22 × 10−3 | 1.69 × 10−2 | na | na |
| Be | 4.57 × 10−4 | 4.57 × 10−4 | 2.56 × 10−21 | 6.13 × 10−22 | 3.55 × 10−4 | 2.88 × 10−3 | na | na | 1.56 × 10−3 | 8.19 × 10−3 | na | na |
| Cd | 1.95 × 10−3 | 1.95 × 10−3 | 1.16 × 10−20 | 2.78 × 10−21 | 1.49 × 10−3 | 1.16 × 10−2 | na | na | 6.65 × 10−6 | 3.49 × 10−5 | na | na |
| Co | 6.63 × 10−3 | 6.63 × 10−3 | 4.85 × 10−20 | 1.16 × 10−20 | 1.00 × 10−2 | 7.51 × 10−2 | na | na | 4.53 × 10−2 | 2.38 × 10−1 | na | na |
| Cr(III) | 1.21 × 10−8 | 2.82 × 10−8 | na | na | 7.57 × 10−5 | 5.48 × 10−4 | na | na | 3.47 × 10−4 | 1.82 × 10−3 | na | na |
| Cr(VI) | 1.52 × 10−2 | 1.52 × 10−2 | 7.11 × 10−17 | 1.70 × 10−17 | 3.74 × 10−2 | 2.62 × 10−1 | 1.92 × 10−5 | 3.36 × 10−5 | 1.74 × 10−1 | 9.10 × 10−1 | 8.92 × 10−5 | 1.17 × 10−4 |
| Cu | 6.27 × 10−7 | 1.46 × 10−6 | na | na | 3.83 × 10−3 | 2.60 × 10−2 | na | na | 1.80 × 10−2 | 9.44 × 10−2 | na | na |
| Fe | 1.16 × 10−5 | 2.72 × 10−5 | na | na | 7.01 × 10−2 | 4.62 × 10−1 | na | na | 3.34 × 10−1 | 1.75 × 100 | na | na |
| Li | 2.13 × 10−6 | 4.96 × 10−6 | na | na | 1.26 × 10−2 | 8.09 × 10−2 | na | na | 6.10 × 10−2 | 3.20 × 10−1 | na | na |
| Mn | 2.11 × 10−1 | 2.11 × 10−1 | na | na | 3.08 × 10−2 | 1.92 × 10−1 | na | na | 1.50 × 10−1 | 7.88 × 10−1 | na | na |
| Ni | 4.60 × 10−3 | 4.60 × 10−3 | 5.25 × 10−18 | 1.26 × 10−18 | 1.43 × 10−3 | 8.68 × 10−3 | na | na | 7.07 × 10−5 | 3.71 × 10−4 | na | na |
| Pb | 4.92 × 10−6 | 1.15 × 10−5 | 2.48 × 10−10 | 1.45 × 10−10 | 2.82 × 10−2 | 1.67 × 10−1 | 1.42 × 10−6 | 2.11 × 10−6 | 1.41 × 10−1 | 7.41 × 10−1 | 7.12 × 10−6 | 9.34 × 10−6 |
| Sn | 4.20 × 10−9 | 9.79 × 10−9 | na | na | 2.38 × 10−5 | 1.38 × 10−4 | na | na | 1.21 × 10−4 | 6.32 × 10−4 | na | na |
| Sr | 4.72 × 10−8 | 1.10 × 10−7 | na | na | 2.64 × 10−4 | 1.50 × 10−3 | na | na | 1.35 × 10−3 | 7.10 × 10−3 | na | na |
| V | 5.08 × 10−3 | 5.08 × 10−3 | na | na | 6.69 × 10−3 | 3.71 × 10−2 | na | na | 3.47 × 10−2 | 1.82 × 10−1 | na | na |
| Zn | 3.91 × 10−6 | 9.12 × 10−6 | na | na | 2.14 × 10−2 | 1.16 × 10−1 | na | na | 1.12 × 10−1 | 5.89 × 10−1 | na | na |
| Zr | 1.15 × 10−5 | 2.67 × 10−5 | na | na | 6.20 × 10−2 | 3.31 × 10−1 | na | na | 3.29 × 10−1 | 1.73 × 100 | na | na |
| Total | 1.32 × 10+1 | 1.66 × 10+1 | 2.67 × 10−5 | 8.53 × 10−8 | 3.36 × 10−1 | 2.21 × 100 | 2.67 × 10−5 | 4.93 × 10−5 | 1.45 × 100 | 7.61 × 100 | 9.77 × 10−5 | 1.28 × 10−4 |
| Adult total HQ | 1.50 × 10+1 | |||||||||||
| Child total HQ | 2.64 × 10+1 | |||||||||||
| Adult total CR | 1.51 × 10−4 | |||||||||||
| Child total CR | 1.77 × 10−4 | |||||||||||
na: not available, due to missing toxicological data; –: not applicable to the available data.
Regarding the inhalation of deposited PM, the decreasing order of the largest impact on non-carcinogenic risk values, in both adults and children, was determined as follows: Mn > Al > As > Cr(VI) > Co > V > Ni > Ba > Cd > Be > Fe > Zr > Pb > Zn > Li > Cu > Sr > Cr(III) > Sn, and, as regards carcinogenic risk: Pb > Cr(VI) > Ni > As > Co > Cd > Be. Regarding the accidental ingestion of deposited PM, the decreasing order of the largest impact on non-carcinogenic was determined as follows: in adults, Fe > Zr > As > Cr(VI) > Mn > Pb > Zn > Li > Co > Al > V > Cu > Cd > Ni > Ba > Be > Sr > Cr(III) > Sn; in children, Fe > As > Zr > Cr(VI) > Mn > Pb > Zn > Al > Li > Co > V > Cu > Cd > Ni > Ba > Be > Sr > Cr(III) > Sn. Regarding the accidental ingestion of deposited PM, the decreasing order of the largest impact on carcinogenic risk, in both adults and children, was determined as follows: Cr(VI) > As > Pb. Regarding dermal contact with deposited PM, the decreasing order of the largest impact on non-carcinogenic risk, in both adults and children, was determined as follows: Fe > Zr > Cr(VI) > Mn > Pb > Zn > Li > Co > Al > V > Cu > As > Ba > Be > Sr > Cr(III) > Sn > Ni > Cd, and as regards carcinogenic risk, Cr(VI) > Pb > As.
4. Discussion
Our research project presented here was based on the average data obtained from all the monitoring stations installed in Kraków. The general tendency of pollutant contents decrease (except for O3) in the ambient air over the years included might be caused by the following: fuel desulphurisation, liquidation of heavy industry and implementation of ecological technologies in industry, gradual modernisation of car fleets in Kraków, poor-quality stove replacement, and using better-quality fuels for house heating purposes until the city of Kraków introduced the prohibition of burning coal and wood (not to mention waste) on 1 September 2019. The significant decrease in the mean year contents of pollutants between 2006 and 2007 might have been caused by cold winters in 2006 and in previous years. It might cause the increase in emissions from heating sources, which, in the absence of conditions for the spread of pollutants, resulted in an increase in their concentration in the air, i.e., PM and SO2 [59]. Moreover, during cold weather, inhabitants use individual vehicles more often than public transport, which might have caused the increase in the NO2 contents in the air. On the other hand, the factors affecting the increase in the O3 contents might involve increased air temperatures and the presence of other air contaminants, i.e., NO2, CO, and volatile organic compounds (VOCs). Observed higher contents of heavy metals and polycyclic aromatic hydrocarbons (PAHs) in winter months in comparison to summer months could result from their content in PM particles [60]. Air quality improvement in Kraków is hindered by the adverse location of the city in the river valley, which is described in the Introduction section. Besides, poor-quality air keeps flowing into the city from the surrounding small towns and villages where strict control measures of solid-fuel burning for house heating purposes have not been introduced. Moreover, ventilation of the city is also reduced as a result of constant development blocking local air-flow corridors. Traffic remains a continuous problem because the number of vehicles keeps increasing in Kraków, while the average age of cars was estimated at about 14 years in Poland in 2018. Higher contents of SO2, CO, C6H6, PM10, and PM2.5 and heavy metals and PAHs, contained in PM particles [60] observed in winter months in comparison to summer months, indicated that local emission sources were the main causes of pollution [6,7]. It needs to be added here that in the past several years, winters become milder, and freezing temperatures shifted from November to March in Poland [61,62]. On the contrary, higher O3 pollution contents were observed in summer rather than winter months. That again could point at summer insolation being the main source of that pollutant [63]. In the case of NO2, no significant changes in monthly contents were observed, which indicated that traffic was the main source of that pollutant in Kraków [64]. Besides, the residents used their vehicles more frequently in cold and rainy weather, which contributed to the increase of traffic and traffic jams. On the other hand, the slight decreases recorded in the summer months could be correlated with school and college holidays, reducing traffic in the university city of Kraków. Exceedance of 24 h contents of PM2.5 and PM10 in March 2018 could be correlated with cold weather during the first 11 and last nine days of the month and low wind speed generally below 5.4 m/s representing up to a gentle breeze in the Beaufort scale of wind speed, indicating that house heating was the main cause of pollution. No correlation with weekdays or weekends was observed in that case. On the contrary, an exceedance of 24 h contents of O3 in July 2018 could be correlated with high temperatures occurring on 4–6 July 2018 and 21–22 July 2018 as well as with the low wind speed during these days. In addition, in that case, no correlation with weekdays or weekends was observed. According to the Polish AQI index, increased contents of PM10, PM2.5, and C6H6 in the first 11 days and last nine days of March, especially from 20:00 to 09:00 the following day, indicated that the figures were correlated with poor-quality fuel and waste burning for house heating purposes in equally poor-quality stoves. The increase of NO2 contents was observed in the morning and evening hours, which could indicate the effect of traffic during the rush hours. Increased contents of O3 during the whole day, from 18 to 19 March 2018, could point at a correlation with high temperatures and moderate wind speed during those days. Besides, during that whole period in March, high contents of pollutants in midday hours could be associated with insolation. The calculated EF values indicated anthropogenic sources of elements (EF > 30) only in the case of Zn. As for Cd, a small proportion of anthropogenic sources was determined. Regarding Pb and Sn, non-crustal sources of elements were revealed. Crustal sources of elements were defined for As, Ba, Be, Co, Cr, Cu, Li, Mn, Ni, Sr, Ti, Tl, and V.
One could expect that during the lockdown and “stay home” campaign, from March to May 2020, air quality should have significantly improved in the context of the COVID-19 pandemic crisis, while the pollutant contents should have effectively decreased, since people travelled less often. The decreases in the monthly contents observed for PM2.5, PM10, and C6H6 could be also caused by high temperatures and reduced house heating requirements. Slight decreases of monthly contents in the case of NO2 could have been caused by reduced traffic rates in Kraków, owing to the lockdown. Upon our analysis of the contents of the above-mentioned pollutants in March 2020 and March 2018, a double decrease in contents was observed in March 2020 in comparison to March 2018. However, that decrease could have also been caused by milder winters and the implementation of the antismog resolution in Kraków. However, daily and hourly air-pollutant content changes in the first five months of 2020 did not confirm the existence of such a trend. That could have resulted from the fact that some residents still had to work out of home and traffic remained the critical cause of air pollution in large cities. Moreover, during the lockdown in Kraków, dry weather and a lack of rainfall caused contaminants to remain suspended in the air, with the occurrence of the resuspension of contaminants from the ground. Additionally, low night-time temperatures caused an increase of fuel burning for heating purposes, as the majority of residents stayed at home during that period. On the other hand, air quality in Kraków itself, as regards the PM contents, improved in comparison to that of the surrounding communes where the antismog resolution had not been adopted. That relationship could be observed on the Airly maps, which are based on a large number of air-pollution sensor measurements in the Airly network [65]. Unfortunately, the unfavourable geographic location of Kraków prevented ventilation of the city and worsened air quality, owing to the inflow of air masses from surrounding areas.
Considering the analysed exposure pathways, the values of the decreasing participation in non-carcinogenic risk, in both adults and children, were arranged as follows: inhalation > dermal contact > accidental ingestion. As to carcinogenic risk, the decreasing participation of exposure pathways, in both adults and children, was as follows: dermal contact > ingestion > inhalation. Depending on the availability of data regarding non-carcinogenic risk, the largest impact of the ambient air on the inhalational pathway was determined as follows, in decreasing order: PM2.5 > PM10 > BaP(PM10) > NO2 > C6H6 > As (PM10) > Cd (PM10) > Ni (PM10) > Pb (PM10). As to the carcinogenic risk of the ambient air in the inhalational pathway, the decreasing order of the largest impact on risk values was set as follows: Pb (PM10) > C6H6 > As (PM10) > BaP (PM10) > Cd (PM10) > DBahA (PM10) > BaA (PM10) > BjF (PM10) > BbF (PM10) > BkF (PM10) > Ni (PM10).
Limitations and Strengths of the Study
However, those data could falsify the real trends developing in particular districts of the city, as they strongly depended on the local atmospheric and topographic conditions [66,67]. Nevertheless, in our research, the average Kraków values were investigated, taking into account the long-term impact on human health. Besides, when describing the general tendency of changes in pollution contents, local atmospheric and topographic conditions should also be considered [68]. However, again, the most important conclusion, which was drawn from this point of view, was that in the past several years, the contents of some pollutants, mainly of PM, exceeded significantly and constantly either the permissible values or the recommended values when the former values were not available [48]. As our PM analysis determined, the most significant pollutant enrichment factors were found in deposited PM samples, which was confirmed by the results of Li et al. [69], Men et al. [70], and Jahandari [71]. In our approach, heavy metals and PAHs were not analysed, as they were measured in PM10, and no permissible or recommended values were available for those substances. Our analysis further concluded that enrichment factor values from the risk assessment point of view were underestimated in the suspended PM, since measured results were available only in respect of four metals and only for the PM10 fraction. Thus, according to the conservative risk assessment principle, the enrichment factor values of deposited PM were used in our health risk assessment. Moreover, hexavalent and trivalent Cr were assumed in maximum concentrations in our risk assessment at the same time, since only general chromium was determined in our laboratory analysis. The heavy metal speciation in the PM is crucial [72]; however, the calculated risk values for both types of chromium were irrelevant here, in comparison to the shares of other pollutants in that case scenario. As to Ba, Be, Li, Mn, Sn, Sr, Ti, and V, ecological risk values were not defined due to the lack of adverse ecological effect values. Additionally, since health risk assessment depends on toxicological data mostly, there is no one and only method for risk calculation. Thus, depending on the input data available and the approach applied, results may differ [36,38] and generate inaccuracies when comparing such results. Nevertheless, the main goal of our investigations was to determine the long-term health impact on the Kraków residents, because a sufficient improvement of air quality will take years.
5. Conclusions
Our studies revealed a general decreasing tendency of annual pollutant contents on the basis of the investigated pollutant data available for the last 15 years. Annual permissible pollutant levels were exceeded in almost all those years, in the cases of PM10, PM2.5, and NO2. High contents of SO2, CO, C6H6, PM10, and PM2.5, as well as those of As, Pb, Cd, Ni, and PAHs were observed in PM particles in winter rather than in summer months, indicating that burning solid fuels for house heating purposes was the main source of pollution. Regarding NO2, no significant changes were observed in monthly contents, which indicated that traffic was the main source of that pollutant in Kraków. In winter months, the recommended 24 h PM2.5 and PM10 contents were constantly exceeded. Occasionally in summer months, the excess of permissible 24 h level of O3 was determined, which was correlated with high temperatures and the presence of ozone precursors in the ambient air. Particulate matter was defined as the most significant air pollutant, while the calculated enrichment factors revealed a significant PM enrichment with heavy metals. Total non-carcinogenic risk values exceeded the acceptable levels, and they were equal to 15.0 in adults and 26.4 in children. Total carcinogenic risk exceeded the acceptable levels as well, since the cancer risk value was equal to 1.51 × 10−4 in adults and 1.77 × 10−4 in children. The pollutants generating the highest values of non-carcinogenic risk were PM2.5, BaP, PM10, and NO2 in the inhalational pathway. The highest carcinogenic risk values were generated by Pb and Cr(VI) in the inhalational pathway and Pb, As, and Cr(VI) in the accidental ingestion and dermal contact pathways. Our health risk assessment, based on the resident exposure scenario, revealed a significant health risk for the residents arising from poor air quality in Kraków.
Supplementary Materials
The following are available online at https://www.mdpi.com/1660-4601/17/17/6063/s1, Figure S1. A demonstrative wind rose in Kraków Poland: share of wind directions in % (a), and wind speed distribution in m/s (b), divided into cool and warm half-years. Figure S2. Location of air-flow corridors and Regional Environmental Protection Inspectorate air monitoring stations in Kraków. Table S1. Description of the air monitoring stations operated by the Regional Environmental Protection Inspectorate (REPI) in Kraków. Table S2. Ranges of the 1 h concentrations in the Polish air quality index (AQI) for selected pollutants. Table S3. The Polish AQI index and the corresponding health recommendations for residents. Table S4. Description of the enrichment indices used in the study. Table S5. Exposure parameters used for the risk assessment calculations under resident scenario in the study. Table S6. Toxicological parameters used for the risk assessment calculations under resident scenario in the study. Table S7. Changes in annual air pollutant contents in Kraków in 2005–2020, with permissible levels. Table S8. Changes in monthly air pollutant contents in 2018 in Kraków; average values of all the monitoring stations. Table S9. Changes in daily air pollutant contents in a selected winter month, average values for Kraków, March 2018, with recommended concentrations. Table S10. Changes in daily air pollutant contents in a selected summer month, average values for Kraków, July 2018, with recommended concentrations. Table S11. Daily and hourly SO2 content changes, with the hourly Polish AQI index, average values for Kraków, March 2018. Table S12. Daily and hourly CO content changes, with the hourly Polish AQI index, average values for Kraków, March 2018. Table S13. Changes in monthly air-pollutant contents in the first half of 2020 in Kraków, average values from all the monitoring stations. Table S14. Estimated daily intake values for the resident of Kraków, in reference to exposure pathways.
Author Contributions
Conceptualization, A.G.-K.; methodology, A.G.-K.; validation, A.G.-K. and P.T.; formal analysis, A.G.-K. and P.T.; investigation, A.G.-K. and P.T.; resources, A.G.-K. and P.T.; data curation, A.G.-K. and P.T.; writing—original draft preparation, A.G.-K. and P.T.; writing—review and editing, A.G.-K. and P.T.; visualization, P.T.; supervision, A.G-K.; project administration, A.G.-K.; funding acquisition, A.G.-K. All authors have read and agreed to the published version of the manuscript.
Funding
This research was funded by the AGH University of Science and Technology, Statutory Research grant number 16.16.140.315. The APC was funded by the AGH University of Science and Technology.
Conflicts of Interest
The authors declare no conflict of interest.
References
- 1.Nowicki M., Ribbe L. Problems of Eco-Development in Poland. Agencja Reklamowo; Wroclaw, Poland: 2001. [Google Scholar]
- 2.Manecki A. Alphabet of Memories: About People of Science and Events of the Past. Wydawnic-two Mineralogiczne Mineral press; Kraków, Poland: 2015. [Google Scholar]
- 3.Kleczkowski P. Smog in Poland. Causes, Effects, Prevention. Wydawnictwo Naukowe PWN S.A.; Warszawa, Poland: 2019. [Google Scholar]
- 4.World Health Organization . WHO Ambient Air Pollution Database May 2016. World Health Organization; Geneva, Switzerland: 2016. [Google Scholar]
- 5.Polish City Registers Second Worst Air Pollution in the World as Smog Descends on Poland, Notes from Poland. [(accessed on 28 May 2020)]; Available online: https://notesfrompoland.com/2020/01/17/polish-city-registers-second-worst-air-pollution-in-the-world-as-smog-descends-on-poland/
- 6.Jedrychowski W., Maugeri U., Jedrychowska-Bianchi I., Flak E. Effect of indoor air quality in the postnatal period on lung function in pre-adolescent children: A retrospective cohort study in Poland. Public Health. 2005;119:535–541. doi: 10.1016/j.puhe.2004.10.016. [DOI] [PubMed] [Google Scholar]
- 7.Jedrychowski W.A., Perera F.P., Spengler J.D., Mroz E., Stigter L., Flak E., Majewska R., Klimaszewska-Rembiasz M., Jacek R. Intrauterine exposure to fine particulate matter as a risk factor for increased susceptibility to acute broncho-pulmonary infections in early childhood. Int. J. Hyg. Environ. Health. 2013;216:395–401. doi: 10.1016/j.ijheh.2012.12.014. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8.Adamiec E., Jarosz-Krzemińska E., Wieszała R. Heavy metals from non-exhaust vehicle emissions in ur-ban and motorway road dusts. Environ. Monit. Assess. 2016;188:369. doi: 10.1007/s10661-016-5377-1. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9.Biuletyn Informacji Publicznej Urząd Marszałkowski Województwa Małopolskiego. [(accessed on 26 May 2020)]; Available online: https://bip.malopolska.pl/umwm,a,1283900,uchwala-nr-xxxii45217-sejmiku-wojewodztwa-malopolskiego-z-dnia-23-styczna-2017-r-w-sprawie-wprowadze.html.
- 10.Bokwa A. Environmental impact of long-term air pollution changes in Krakow, Poland. Polish J. of Environ. Stud. 2008;5:673–686. [Google Scholar]
- 11.Samek L. Chemical characterization of selected metals by X-ray fluorescence method in particulate matter collected in the area of Krakow, Poland. Microchem. J. 2009;92:140–144. doi: 10.1016/j.microc.2009.02.007. [DOI] [Google Scholar]
- 12.Wilczyńska-Michalik W., Michalik M. Composition and origin of dust particles in atmosphere in Kraków. Aura. 2015;3:12–16. doi: 10.14199/2.2015.3.3. [DOI] [Google Scholar]
- 13.Wilczyńska-Michalik W., Pietras B., Samek L., Furman L., Łatkiewicz A., Rzeźnikiewicz K., Michalik M. Submicrometer particles in air pollution in Kraków. Aura. 2015;8:4–7. [Google Scholar]
- 14.Choi H., Melly S.J., Spengler J. Intraurban and Longitudinal Variability of Classical Pollutants in Kraków, Poland, 2000–2010. Int. J. Environ. Res. Public Health. 2015;12:4967–4991. doi: 10.3390/ijerph120504967. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15.Samek L., Stegowski Z., Furman L., Fiedor J. Chemical content and estimated sources of fine fraction of particulate matter collected in Krakow. Air. Qual. Atmos. Health. 2016;10:47–52. doi: 10.1007/s11869-016-0407-2. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 16.Samek L. Overall human mortality and morbidity due to exposure to air pollution. Int. J. Occup. Med. Environ. Health. 2016;29:417–426. doi: 10.13075/ijomeh.1896.00560. [DOI] [PubMed] [Google Scholar]
- 17.Bogacki M., Bździuch P. Predicting the Spatial Distribution of Emissions from Urban Buses Based on Previ-ously Measured Data and Scenarios for Their Modernization in the Future. Case Study: Kraków, Poland. Atmos. Environ. 2019;199:1–14. doi: 10.1016/j.atmosenv.2018.11.009. [DOI] [Google Scholar]
- 18.Rzeszutek M., Bogacki M., Bździuch P., Szulecka A. Improvement assessment of the OSPM model per-formance by considering the secondary road dust emissions. Transport. Res. D Tr. E. 2019;68:137–149. doi: 10.1016/j.trd.2018.04.021. [DOI] [Google Scholar]
- 19.Biuletyn Informacji Publicznej . Change in the Study of Conditions and Directions for Spatial Development of the City of Krakow. Urząd Miasta Krakowa; Kraków, Poland: 2013. [Google Scholar]
- 20.Ośródka L., Godłowska J., Hajto M., Rozwoda W., Wojtylak M. Determining the Anemological Conditions for the Area of Kraków on the Basis of Data from the Institute of Meteorology and Water Management Observation and Measurement Network. KHK S.A.; Kraków, Poland: 2010. [Google Scholar]
- 21.Bini C., Bech J. PHEs, Environment and Human Health-Potentially Harmful Elements in the Environment and the Impact on Human Health. Springer; Raton, NM, USA: 2014. [Google Scholar]
- 22.Peters A., Dockery D.W., Muller J.E., Mittleman M.A. Increased particulate air pollution and the triggering of myocardial infarction. Circulation. 2001;103:2810–2815. doi: 10.1161/01.CIR.103.23.2810. [DOI] [PubMed] [Google Scholar]
- 23.Brunekreef B., Holgate S.T. Air pollution and health. Lancet. 2002;360:1233–1242. doi: 10.1016/S0140-6736(02)11274-8. [DOI] [PubMed] [Google Scholar]
- 24.Pope C.A., III, Burnett R.T., Thun M.J., Calle E.E., Krewski D., Ito K., Thurston G.D. Lung cancer, car-diopulmonary mortality and long-term exposure to fine particulate air pollution. JAMA. 2002;287:1132–1141. doi: 10.1001/jama.287.9.1132. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 25.Rajagopalan S., Al-Kindi S.G., Brook R.D. Air pollution and cardiovascular disease. J. Am. Coll. Cardiol. 2018;72:2054–2070. doi: 10.1016/j.jacc.2018.07.099. [DOI] [PubMed] [Google Scholar]
- 26.Samet J.M., Dominici F., Curriero F.C., Coursac I., Zeger S.L. Fine particulate air pollution and mortality in 20 U.S. Cities, 1987–1994. New Engl. J. Med. 2000;343:1742–1749. doi: 10.1056/NEJM200012143432401. [DOI] [PubMed] [Google Scholar]
- 27.Polichetti G., Cocco S., Spinali A., Trimarco V., Nunziata A. Effects of particulate matter (PM10, PM2.5 and PM1) on the cardiovascular system. Toxicology. 2009;261:1–8. doi: 10.1016/j.tox.2009.04.035. [DOI] [PubMed] [Google Scholar]
- 28.Lippmann M., Chen L.C., Gordon T., Ito K., Thurston G.D. National particle component toxicity (NPACT) Initiative: Integrated epidemiologic and toxicologic studies of the health effects of particulate matter components. Res Rep. Health Eff. Inst. 2013;177:5–13. [PubMed] [Google Scholar]
- 29.Wang M., Beelen R., Stafoggia M., Raaschou-Nielsen O., Andersen Z.J., Hoffmann B., Fischer P., Houthuijs D., Nieuwenhuijsen M., Weinmayr G., et al. Long-term exposure to elemental constituents of particulate matter and cardiovascular mortality in 19 European cohorts: Results from the ESCAPE and TRANSPHORM projects. Environ. Int. 2014;66:97–106. doi: 10.1016/j.envint.2014.01.026. [DOI] [PubMed] [Google Scholar]
- 30.Chau T.-T., Wang K.-Y. An association between air pollution and daily most frequently visits of eighteen outpatient diseases in an industrial city. Sci. Rep. 2020;10:1–21. doi: 10.1038/s41598-020-58721-0. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 31.Zuśka Z., Kopcińska J., Dacewicz E., Skowera B., Wojkowski J., Ziernicka-Wojtaszek A. Application of the Principal Component Analysis (PCA) method to assess the impact of meteorological elements on con-centrations of particulate matter (PM10): A case study of the Mountain Valley (the Sącz Basin, Poland) Sustainability. 2019;11:6740. doi: 10.3390/su11236740. [DOI] [Google Scholar]
- 32.Kastury F., Smith E., Juhasz A.L. A critical review of approaches and limitations of inhalation bioavaila-bility and bioaccessibility of metal (loid)s from ambient particulate matter or dust. Sci. Total. Environ. 2017;574:1054–1074. doi: 10.1016/j.scitotenv.2016.09.056. [DOI] [PubMed] [Google Scholar]
- 33.Ahmad H.R., Mehmood K., Sardar M.F., Maqsood M.A., Rehman M.Z.U., Zhu C., Li H. Integrated risk assessment of potentially toxic elements and particle pollution in urban road dust of megacity of Pakistan. Hum. Ecol. Risk Assess. Int. J. 2019;26:1810–1831. doi: 10.1080/10807039.2019.1611415. [DOI] [Google Scholar]
- 34.Musa A., Hamza S.M., Kidak R. Street dust heavy metal pollution implication on human health in Nicosia, North Cyprus. Environ. Sci. Pollut. Res. 2019;26:28993–29002. doi: 10.1007/s11356-019-06028-7. [DOI] [PubMed] [Google Scholar]
- 35.Kadhum S.A. A preliminary study of heavy metals pollution in the sandy dust storms and its human risk assessment from middle and south of Iraq. Environ. Sci. Pollut. Res. 2020;27:8570–8579. doi: 10.1007/s11356-019-07380-4. [DOI] [PubMed] [Google Scholar]
- 36.Gruszecka-Kosowska A., Wdowin M. The mineralogy, geochemistry and health risk assessment of depos-ited particulate matter (PM) in Kraków, Poland. Geol. Geophys. Environ. 2016;42:429–441. doi: 10.7494/geol.2016.42.4.429. [DOI] [Google Scholar]
- 37.Pachurka Ł., Gruszecka-Kosowska A., Kobus D., Sówka I. Ecological Chemistry and Engineering A—Chemia i Inżynieria Ekologiczna A. Society of Ecological Chemistry and Engineering; Opole, Poland: 2018. Assessment of inhalational exposure of resi-dents of Wroclaw, Kraków and Warszawa to benzo[a]pyrene. [Google Scholar]
- 38.Gruszecka-Kosowska A. Assessment of the Kraków inhabitants’ health risk caused by the exposure to inhalation of outdoor air contaminants. Stoch. Env Res. Risk A. 2018;32:485–499. doi: 10.1007/s00477-016-1366-8. [DOI] [Google Scholar]
- 39.Regional Environmental Protection Inspectorate in Kraków, Poland Wojewódzki Inspektorat Ochrony Środowiska w Krakowie. [(accessed on 26 May 2020)]; Available online: http://Kraków.pios.gov.pl/
- 40.Regional Environmental Protection Inspectorate in Kraków . Assessment of Air Quality in the Małopolska Voivodeship in 2005. Regional Environmental Protection Inspectorate in Kraków; Kraków, Poland: 2006. [Google Scholar]
- 41.Tarnów Branch . Report on Air Pollution Analysis in the Area of Małopolska Voivodeship in 2005. Environmental Protection Inspection, Regional Environmental Protection Inspectorate in Kraków; Kraków, Poland: 2006. Examination of Air Pollution with Benzene, by the Indicator Method, in Accordance with the Environmental Monitoring Program in the Małopolska Voivodeship in 2005. [Google Scholar]
- 42.Regional Environmental Protection Inspectorate in Kraków . Initial Assessment of Air Quality in the Małopolska Voivodeship in Terms of the Content of Arsenic, Cadmium, Mercury, Nickel and Benzo (a) Pyrene in PM10 Dust and Adjustment of the Assessment System to the Requirements of Directive 2004/107/EC. Regional Environmental Protection Inspectorate in Kraków; Kraków, Poland: 2006. [Google Scholar]
- 43.Regional Environmental Protection Inspectorate in Kraków . Assessment of Air Quality in the Małopolska Voivodeship in 2006 (Verified) Regional Environmental Protection Inspectorate in Kraków; Kraków, Poland: 2007. [Google Scholar]
- 44.Tarnów Branch . Report on Air Pollution Analysis in the Area of Małopolska Voivodeship in 2006. Environmental Protection Inspection, Regional Environmental Protection Inspectorate in Kraków; Kraków, Poland: 2007. Examination of Air Pollution with Benzene, by the Indicator Method, in Accordance with the Environmental Monitoring Program in the Małopolska Voivodeship in 2006. [Google Scholar]
- 45.Tarnów Branch . Report on Air Pollution Analysis with Benzene in the Area of Małopolska Voivodeship in 2007. Environmental Protection Inspection, Regional Environmental Protection Inspectorate in Kraków; Kraków, Poland: 2008. Examination of Air Pollution with Benzene, by the Indicator Method, in Accordance with the Environmental Monitoring Program in the Małopolska Voivodeship for 2007–2009. [Google Scholar]
- 46.Biuletyn Informacji Publicznej . Regulation of the Minister of the Environment Concerning the Levels of Certain SubStances in the Air of 24 August 2012. Urząd Miasta Krakowa; Kraków, Poland: 2012. [Google Scholar]
- 47.European Environment Agency . Air quality in Europe—2019 Report. EEA Report No 10/2019. Publications Office of the European Union; Luxembourg: 2019. [Google Scholar]
- 48.Goddard S.L., Williams K.R., Robins C., Butterfield D.M., Brown R.J.C. Concentration trends of metals in ambient air in the UK: A review. Environ. Monit. Assess. 2019;191:683. doi: 10.1007/s10661-019-7824-2. [DOI] [PubMed] [Google Scholar]
- 49.Gruszecka-Kosowska A. Deposited particulate matter enrichment in heavy metals and related health risk: A case study of Krakow, Poland. Proceedings. 2019;44:1. doi: 10.3390/IECEHS-2-06373. [DOI] [Google Scholar]
- 50.Kabata-Pendias A. Trace Elements in Soils and Plants. 4th ed. CRC Press; Boca Raton, FL, USA: 2011. [Google Scholar]
- 51.Rudnick R., Gao S. Treatise on Geochemistry. 2nd ed. Elsevier Science; Oxford, UK: 2014. Composition of the Continental Crust. [Google Scholar]
- 52.Benson N.U., Adedapo A.E., Fred-Ahmadu O.H., Williams A., Udosen E.D., Ayejuyo O.O., Olajire A.A. New ecological risk indices for evaluating heavy metals contamination in aquatic sediment: A case study of the Gulf of Guinea. Reg. Stud. Mar. Sci. 2018;18:44–56. doi: 10.1016/j.rsma.2018.01.004. [DOI] [Google Scholar]
- 53.Office of Emergency and Remedial Response . Risk Assessment Guidance for Superfund: Human Health Evaluation Manual, Part. A. US Environmental Protection Agency; Washington, DC, USA: 1989. [Google Scholar]
- 54.Office of Emergency and Remedial Response . Risk Assessment Guidance for Superfund Volume I: Human Health Evaluation Manual Supplemental Guidance. US Environmental Protection Agency; Washington, DC, USA: 2009. [Google Scholar]
- 55.Wcisło E., Bronder J., Bubak A., Rodríguez-Valdés E., Gallego J.L.R. Human health risk assessment in restoring safe and productive use of abandoned contaminated sites. Environ. Int. 2016;94:436–448. doi: 10.1016/j.envint.2016.05.028. [DOI] [PubMed] [Google Scholar]
- 56.Ferreira-Baptista L., De De Miguel E. Geochemistry and risk assessment of street dust in Luanda, Angola: A tropical urban environment. Atm. Environ. 2005;39:4501–4512. doi: 10.1016/j.atmosenv.2005.03.026. [DOI] [Google Scholar]
- 57.Office of Solid Waste and Emergency Response . Role of the Baseline Risk Assessment in Superfund Remedy Selection Decisions. US Environmental Protection Agency; Washington, DC, USA: 1991. [Google Scholar]
- 58.Kanchan K., Gorai A.K., Goyal P. A Review on Air Quality Indexing System. Asian J. Atm. Environ. 2015;9:101–113. doi: 10.5572/ajae.2015.9.2.101. [DOI] [Google Scholar]
- 59.Environmental Monitoring Library . Report on the State of the Environment in Małopolska in 2006. Environmental Monitoring Library; Kraków, Poland: 2007. Voivodeship Inspectorate for Environmental Protection in Kraków. [Google Scholar]
- 60.Yadav S., Kumbhar N., Jan R., Roy R., Satsangi P.G. Genotoxic effects of PM10 and PM2.5 bound metals: Metal bioaccessibility, free radical generation, and role of iron. Environ. Geochem. Health. 2018;41:1163–1186. doi: 10.1007/s10653-018-0199-4. [DOI] [PubMed] [Google Scholar]
- 61.Ministry of the Environment Republic of Poland . Polish National Strategy for Adaptation to Climate Change (NAS 2020) with the Perspective by 2030. Ministry of the Environment, Institute of Environmental Protection—National Research Institute; Warsaw, Poland: 2013. [Google Scholar]
- 62.Wójcik R., Miętus M., Miȩtus M. Some features of long-term variability in air temperature in Poland (1951–2010) Przegląd Geograficzny. 2014;86:339–364. doi: 10.7163/PrzG.2014.3.3. [DOI] [Google Scholar]
- 63.Stathopoulou E., Mihalakakou G., Santamouris M., Bagiorgas H.S. On the impact of temperature on tropospheric ozone concentration levels in urban environments. J. Earth Syst. Sci. 2008;117:227–236. doi: 10.1007/s12040-008-0027-9. [DOI] [Google Scholar]
- 64.Kumar A., Mishra R.K. Human health risk assessment of major air pollutants at transport corridors of Delhi, India. J. Transp. Health. 2018;10:132–143. doi: 10.1016/j.jth.2018.05.013. [DOI] [Google Scholar]
- 65.Airly, Airly Maps. [(accessed on 26 May 2020)];2020 Available online: https://airly.eu/map/pl/
- 66.Chalvatzaki E., Chatoutsidou S.E., Lehtomäki H., Almeida S.M., Eleftheriadis K., Hänninen O., Lazaridis M. Characterization of human health risks from particulate air pollution in selected European cities. Atmophere. 2019;10:96. doi: 10.3390/atmos10020096. [DOI] [Google Scholar]
- 67.Zgłobicki W., Telecka M., Skupiński S. Assessment of short-term changes in street dust pollution with heavy metals in Lublin (E Poland)—Levels, sources and risks. Environ. Sci. Pollut. Res. Int. 2019;26:35049–35060. doi: 10.1007/s11356-019-06496-x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 68.Tainio M., Juda-Rezler K., Reizer M., Warchałowski A., Trapp W., Skotak K. Future climate and adverse health effects caused by fine particulate matter air pollution: Case study for Poland. Reg. Environ. Chang. 2012;13:705–715. doi: 10.1007/s10113-012-0366-6. [DOI] [Google Scholar]
- 69.Li H.-H., Chen L.-J., Yu L., Guo Z.-B., Shan C.-Q., Lin J.-Q., Gu Y.-G., Yang Z.-B., Yang Y.-X., Shao J.-R., et al. Pollution characteristics and risk assessment of human exposure to oral bio-accessibility of heavy metals via urban street dusts from different functional areas in Chengdu, China. Sci. Total. Environ. 2017;586:1076–1084. doi: 10.1016/j.scitotenv.2017.02.092. [DOI] [PubMed] [Google Scholar]
- 70.Men C., Liu R., Xu F., Wang Q., Guo L., Shen Z. Pollution characteristics, risk assessment, and source apportionment of heavy metals in road dust in Beijing, China. Sci. Total. Environ. 2018;612:138–147. doi: 10.1016/j.scitotenv.2017.08.123. [DOI] [PubMed] [Google Scholar]
- 71.Jahandari A. Pollution status and human health risk assessments of selected heavy metals in urban dust of 16 cities in Iran. Environ. Sci. Pollut. Res. 2020;27:23094–23107. doi: 10.1007/s11356-020-08585-8. [DOI] [PubMed] [Google Scholar]
- 72.Han X., Lu X., Zhang Q., Wuyuntana. Hai Q., Pan H. Grain-size distribution and contamination characteristics of heavy metal in street dust of Baotou, China. Environ. Earth Sci. 2016;75:468. doi: 10.1007/s12665-016-5316-z. [DOI] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.