Abstract:
Since the Action Plan of Air Pollution Prevention and Control, the PM
2.5 concentrations in key regions has decreased rapidly while O
3 concentration has gradually increased. The demand of coordinated control of PM
2.5 and O
3 is urgent for the Chinese government. Understanding the responses of PM
2.5 and O
3 to changes in precursor emissions and meteorological conditions is of great significance for formulating coordinated control strategies of PM
2.5 and O
3. By using the air quality model and response surface model, this study evaluated the response of 2.5 and 3 concentrations to the changes of precursors and meteorological conditions. Based on the analytical response relationship, policy recommendations on precursor emission reduction, regional division of joint prevention and control, and target setting were proposed. Results show that: (1) VOCs emission reduction is beneficial to reduce both PM
2.5 and O
3 concentration in all provinces. Insufficient NO
x emission reduction will increase O
3 concentration in most key areas and PM
2.5 concentration in Beijing-Tianjin-Hebei region, and the VOCs/NOx emission reduction ratio is 45% and 20% on average to avoid this adverse effect. For the Beijing-Tianjin-Hebei region, the joint control of Henan and Shandong may need to be considered. For the Yangtze River Delta and Pearl River Delta, the joint control of Jiangxi and Fujian may be more important in the future. (3) Meteorological conditions have a great influence on PM
2.5 and O
3 background values. The effects of three-year moving average and five-year moving average on reducing PM
2.5 fluctuation in each region are 35-81% and 60-86%, and the effects of reducing O
3 fluctuation are 40-67% and 53-87%. Applying multi-year moving averages to mitigate the variation of meteorological conditions helps to scientifically set and assess the targets for PM
2.5 and O
3.