Table 3.
Percentage changes in mean (mean ± SE) concentrations of pollutants during COVID-19 lockdown relative to pre-lockdown period.
| Percentage change in CO | Percentage change in PM10 | Percentage change in SO2 | Percentage change in NO2 | Percentage change in O3 | |
|---|---|---|---|---|---|
| Makkah | 15.63% | 26.08% | 4.97% | 44.35% | 18.98% |
| Ha'il | 12.39% | 1.41% | 4.92% | 4.89% | 1.59% |
| Jeddah | 33.60% | 31.94% | 44.16% | 5.89% | 10.04% |
| Jazan | 4.60% | 58.59% | 29.69% | 39.04% | 1.49% |
| Tabuk | 23.57% | 13.02% | 17.50% | 26.49% | −8.48% |
| Al Madinah | 10.11% | 4.42% | 20.18% | 3.17% | 18.91% |
| Al Qasim | 2.04% | 7.62% | 4.92% | 5.86% | −8.48% |
| Riyadh | 16.24% | 91.12% | 35.37% | 20.71% | 24.24% |
| Haql | 3.76% | 14.28% | 28.84% | 29.18% | −1.72% |