Table 3.
Comparison of the CAP concentrations during selected periods in Daegu, South Korea
| Feb 18–Apr 30, 2018 | Feb 18–Apr 30, 2019 | Feb 18–Apr 30, 2020 | Jan 1–Feb 17, 2020 | Differencea | |
|---|---|---|---|---|---|
| PM10 (μg/m3) | 50.6 ± 32.8 | 48.8 ± 27.5 | 37.5 ± 18.9 | 38.9 ± 20.8 | − 1.4 (3.75)b |
| PM2.5 (μg/m3) | 26.2 ± 16.5 | 27.8 ± 19.9 | 19.3 ± 10.7 | 27.9 ± 16.9 | − 8.6 (30.9) |
| O3 (ppb) | 32.3 ± 19.3 | 34.5 ± 19.0 | 33.4 ± 17.8 | 19.6 ± 14.3 | 13.8 (71.1) |
| NO2 (ppb) | 20.4 ± 13.8 | 20.8 ± 13.8 | 16.3 ± 12.1 | 25.8 ± 14.7 | − 9.5 (36.7) |
| CO (ppb) | 425 ± 192 | 478 ± 202 | 409 ± 145 | 726 ± 297 | − 317 (43.7) |
| SO2 (ppb) | 3.1 ± 1.8 | 2.9 ± 1.5 | 2.7 ± 1.2 | 3.4 ± 1.5 | − 0.7 (21.3) |
aDifference between February 18–April 30, 2020, and January 1–February 17, 2020
bConcentration (percentage)