Table 2. Distribution of 4-Year Mean Air Pollutant Concentrations and Pairwise Correlations.
| Pollutant | Annual Concentration, μg/m3 | Spearman Correlation Coefficient | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Based on a Spatial Statistical Model | Based on Air Monitoring Station | |||||||||||
| Mean (SD) | Median (IQR) | 1-IQR Range | >WHO AQG, %a | PM1 | PM2.5 | PM10 | NO2 | PM10 | SO2 | NO2 | O3 | |
| Air pollutants estimated using a spatial statistical model | ||||||||||||
| PM1 | 46.8 (6.5) | 45.2 (41.0-54.1) | 13.1 | NAb | 1 | 0.93c | 0.87c | 0.73c | 0.55c | 0.29c | 0.03 | 0.36c |
| PM2.5 | 54.0 (6.1) | 52.1 (48.8-58.8) | 10.0 | 100 | NA | 1 | 0.97c | 0.85c | 0.49c | 0.33c | 0.13 | 0.35c |
| PM10 | 95.6 (9.8) | 94.6 (89.3-103.1) | 13.8 | 100 | NA | NA | 1 | 0.92c | 0.48c | 0.35c | 0.15 | 0.36c |
| NO2 | 33.6 (4.7) | 32.3 (31.2-38.5) | 7.3 | 7.9 | NA | NA | NA | 1 | 0.48c | 0.26 | 0.14 | 0.35c |
| Measured by local air monitoring stations | ||||||||||||
| PM10 | 88.9 (21.3) | 90.4 (74.4-105.0) | 30.6 | 100 | NA | NA | NA | NA | 1 | 0.58c | 0.47c | 0.85c |
| SO2 | 49.8 (16.0) | 48.4 (38.1-61.5) | 23.4 | 95.8 | NA | NA | NA | NA | NA | 1 | 0.21 | 0.60c |
| NO2 | 36.4 (11.1) | 35 (31.8-44.8) | 13 | 37.5 | NA | NA | NA | NA | NA | NA | 1 | 0.33 |
| O3 | 106.9 (165.8) | 43.8 (30.7-77) | 46.3 | 12.5 | NA | NA | NA | NA | NA | NA | NA | 1 |
Abbreviations: IQR, interquartile range; NA, not applicable; NO2, nitrogen dioxide; O3, ozone; PM1, particle matter with aerodynamic diameter ≤1.0 μm; PM2.5, particle matter with aerodynamic diameter ≤2.5 μm; PM10, particle matter with aerodynamic diameter ≤10 μm; SO2, sulfur dioxide; WHO AQG, World Health Organization air quality guidelines.
a
Compared with the WHO AQG (the WHO AQG for PM2.5, PM10, SO2, NO2, and O3 were 10 μg/m3, 20 μg/m3, 20 μg/m3, 40 μg/m3, and 400 μg/m3, respectively).
b
A guideline for PM1 has not been proposed by WHO or any other organization.
c
P < .05.