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Particulate matter with an aerodynamic diameter of < 2.5 μm (PM2.5) concentrations (μg m−3) in Semnan, Iran in 2019–2021.
| Parameter | Year | ||
|---|---|---|---|
| 2019 | 2020 | 2021 | |
| μg m−3 | |||
| Annual mean | 123.87 | 116.30 | 97.34 |
| Winter mean | 95.23 | 87.21 | 58.94 |
| Summer mean | 112.35 | 105.51 | 98.47 |
| Annual 98th percentile | 123.56 | 111.5 | 98.32 |
| Summer maximum | 145.76 | 116.23 | 102.45 |
| Winter maximum | 148.65 | 123.18 | 117.87 |
