Elucidating Contributions of Anthropogenic Volatile Organic Compounds and Particulate Matter to Ozone Trends over China

• DOI: 10.1021/acs.est.2c03315
• Publication Date: 2022-09-09T21:26:22Z
• Authors: Chi Li; Qindan Zhu; Xiaomeng Jin; Ronald C. Cohen
• Keywords: Nitrogen oxides

In China, emissions of ozone (O3)-producing pollutants have been targeted for mitigation to reduce O3 pollution. However, the observed decrease is slower than/opposite expectations affecting health millions people. For a better understanding this failure and its connection with anthropogenic emissions, we quantify summer trends that would occurred had weather stayed constant by applying numerical tool "de-weathers" observations across 31 urban regions (123 cities 392 sites) over 8 years. are significant (p < 0.05) 234 sites after de-weathering, contrary directly (only 39 due high meteorology-induced variability). The de-weathered data allow categorizing in China into four different groups regarding mitigation, group 1 exhibiting steady reductions, while 4 showing increases. Analysis relationships between odd oxygen nitrogen oxides illustrates how changes NOx, volatile organic compounds (VOCs), reductions fine particulate matter (PM2.5) affect differently these groups. While analysis suggests VOC main driver decreases 1, 3 primarily affected decreasing PM2.5, which results enhanced formation. Our demonstrates both importance possibility isolating emission-driven from climate interpreting short-term air quality observations.