Table 3.
Study results.
| Study and Author | Results | Interpretation |
|---|---|---|
| 1 [25] To et al. | O3 risk for hospitalized patients (OR: 1.06 *, 95% CI: 1.00–1.13) O3 risk for the general population (OR: 1.00, 95% CI: 0.98–1.03) |
Ozone is not significantly associated with incidence nor reproductive number, but it is positively associated with incidence in institutional settings like long-term care homes, hospitals, and jails. A one-unit increase in average weekly ozone is close to being significant for institutional outbreaks but not for the general population. |
| 2 [26] Bilal et al. | O3 coefficient for cases: 0.214 * O3 coefficient for recoveries: 0.216 * O3 coefficient for active cases: 0.467 * O3 coefficient for deaths: 0.215 * |
PM10 and O3 are positively associated with total and active cases. The results for PM2.5, NO2, and cases are mixed depending on whether the outcome is based on active or total cases. O3 and NO2 are significantly positively associated with COVID-19 deaths. PM2.5 is negatively associated with deaths. There is no significant association between PM10 and deaths. |
| 3 [27] Isphording et al. | O3—no significance PM10 1 μg/m3 increase: RR = 1.00042 * |
There are significant positive effects of acute exposure to PM10 on COVID-19 cases for all individuals and for deaths in those over 60 years old. Similar results were observed for ozone, but the effects were quantitatively non-significant. Among male patients aged 60–79 years, a one μg/m3 increase in PM10 two to four days after the onset of illness is associated with 0.042 additional deaths per 100,000 individuals. A one-SD increase in air pollution corresponds to an approximately 24 percent of a standard deviation increase in the fatality rate within this demographic. |
| 4 [28] Dragone et al. | PM10 > 50 μg/m3 PM2.5 > 50 μg/m3 75%< RH < 85% 4 °C < AT < 8 °C −0.5 < NAA < 0.5 |
Based on a spatial analysis, the results indicate that PM2.5, PM10, NH3, and CO are strongly correlated with COVID-19. On the other hand, NO and NO2 show weak correlations, while O3 and SO2 show almost no correlation. However, it is important to note that none of these results reached statistical significance based on the z score values presented in the table. |
| 5 [29] Stufano et al. | NR | In general, there is no evident relationship observed between pollutants and COVID-19 cases. The relationship between the two variables is inconsistent, with both positive and negative associations observed depending on the specific lag period considered. |
| 6 [30] Zoran et al. | O3 coefficient for cases: 0.640 * O3 coefficient for deaths: 0.690 * |
NO2 is negatively and statistically significantly associated with total cases, incidence, and total deaths. On the other hand, O3 is positively and statistically significantly associated with total cases, incidence, and total deaths. |
| 7 [31] Kutralam-Muniasamy et al. | PM10 coefficient for deaths: −0.380 * CO coefficient for deaths: 0.860 * O3 coefficient for deaths: 0.490 * |
PM2.5, NO2, and SO2 did not exhibit significant associations with cases or deaths. However, PM10 displayed a negative association with both cases and deaths. On the other hand, CO and O3 showed positive associations with cases and deaths. These findings suggest that higher levels of CO and O3 were linked to increased cases and deaths related to COVID-19. The associations observed for PM10, CO, and O3 were statistically significant. |
| 8 [32] Linares et al. | O3 incidence risk (RR: 1.007 *, 95% CI: 1.004–1.009) | In all eight regions analyzed, NO2 showed a positive association with COVID-19 cases in terms of incidence rates. Additionally, in six out of the eight regions, NO2 displayed a positive association with hospitalizations. Similarly, PM10 exhibited a positive association with cases in six regions and hospitalizations in three regions. Furthermore, O3 demonstrated a positive association with cases in four regions and hospitalizations in three regions. These findings indicate that air pollutants, especially NO2, are closely linked to both the incidence and severity of COVID-19. |
| 9 [33] Meo et al. | O3 incidence risk (RR: 1.008 *) O3 death risk (RR: 1.044 *) |
A 1 μm increase in PM2.5 was found to be significantly associated with a 1.1% increase in cases and a 2.3% increase in deaths. Similarly, a 1-unit increase in the CO level is significantly associated with a 21.3% increase in cases and a 21.8% increase in deaths. Furthermore, a 1-unit rise in O3 is significantly associated with a 0.8% increase in cases and a 4.4% increase in deaths. |
| 10 [34] Meo et al. | O3 incidence risk (RR: 1.025 *) O3 coefficient for cases: 0.158 * O3 coefficient for deaths: 0.034 |
The analysis revealed positive associations between PM2.5 and CO with both COVID-19 cases and deaths. Additionally, O3 was found to have a positive association with cases, but the association with deaths was not statistically significant. Moreover, the results of a Poisson regression indicated that a 1 μm increase in PM2.5 resulting from wildfires led to a 0.4% increase in the number of deaths. |
| 11 [35] Persico et al. | NR | Both PM2.5 and O3 show positive associations with both cases of and deaths due to COVID-19. Specifically, an 11.8 percent increase in PM2.5, corresponding to an increase of 0.778 mg/m3, is associated with a 53 percent increase in cases. Similarly, a 5 percent increase in ozone is associated with a 10 percent increase in deaths due to COVID-19. These findings highlight the potential impact of air pollution, particularly PM2.5 and O3, on the incidence and severity of COVID-19 cases. |
| 12 [36] Gujral et al. | O3 incidence risk (OR: 4.66, 95% CI: 0.85–8.47) | An increase of one unit in PM2.5, PM10, and O3 is correlated with a decrease of 4.51%, a decrease of 1.62%, and an increase of 4.66% in daily COVID-19 cases, respectively. These findings indicate that higher levels of PM2.5 are associated with a decrease in COVID-19 cases, while higher levels of O3 are linked to an increase in cases. The effects of PM10 on cases is relatively smaller, with a slight decrease observed. |
| 13 [37] Adhikari et al. | O3 incidence risk (OR: 10.51 *, 95% CI: 7.47–13.63) | A one-unit increase in the moving average of PM2.5 was associated with a 33.11% decrease in daily COVID-19 incidence. On the other hand, a one-unit increase in the moving average of ozone was associated with a 10.51% increase in incidence. Regarding COVID-19 deaths, there was no significant association found with either PM2.5 or ozone (O3) based on the analysis. |
| 14 [38] Rui et al. | NR | The density of total atmospheric ozone is negatively associated with the incidence of cases. |
| 15 [39] Karimi et al. | O3 death risk (OR: 2.0, 95% CI: 0.10–3.60) | The analysis did not find a significant association between PM2.5 and COVID-19-related deaths. However, a one ppb increase in the average ozone concentration was associated with a 2.0% decrease in COVID-19-related deaths. |
| 16 [40] Kim et al. | O3 death risk (OR: 29.0 *, 95% CI: 9.9–51.5) | A high percentage of the population (98.9%) had ozone (O3) levels below the maximum 8 h national ambient air quality standard (NAAQS) of 35.7 μg/m3 or 70 parts per billion. An IQR increase in 3-day O3 exposure (8.2 μg/m3) was associated with a 29.0% increase in the risk of COVID-19 mortality. The associations varied depending on demographics, race/ethnicity, and comorbid conditions, indicating potential modifiers of the observed associations. |
| 17 [41] Akan et al. | O3 coefficient for cases: −0.620 * | As the concentration of O3 increases, there tends to be a decrease in the number of reported cases of the particular condition under study. |
| 18 [42] Wiśniewski et al. | O3 coefficient for cases: −0.299 * | As the concentration of O3 increases, there tends to be a decrease in the number of reported cases of the particular condition under study. |
*—statistically significant; OR—odds ratio; CI—confidence interval; SD—standard deviation.