| Table 1b. Comparison of ambient PM2.5 concentration between Group 1 (2017, 2018 and 2020) and 2 (2019 and 2021). | |||
| Ambient PM2.5 concentration (µg/m3) |
Group 1 (2017,2018,2020) |
Group 2 (2019,2021) |
p-value |
|---|---|---|---|
| Maximum value | 42.5±29.4 | 56.9±49.4 | <0.001* |
| Mean value | 24.5±17.2 | 30.7±24.0 | <0.001* |