Driving Forces of Meteorology and Emission Changes on Surface Ozone in the Huaihe River Basin, China

Surface ozone ( O 3 ) pollution in China has become a serious environmental problem in recent years. In the present study, we targeted the HRB, a large region located in China’s north–south border zone, to assess the driving forces of meteorology and emission changes on surface ozone. A Kolmogorov–Zurbenko ( KZ ) filter method was performed on the maximum daily average 8-h (MDA8) concentrations of ozone in the HRB during 2015–2020 to decompose the original time series. The findings demonstrated that the short-term ( O 3 ST ), seasonal ( O 3 SN ), and long-term components ( O 3 LT ) of MDA8 O 3 variations accounted for 34.2%, 56.1%, and 2.9% of the total variance, respectively. O 3 SN has the greatest influence on the daily variation in MDA8 O 3 , followed by O 3 ST . In coastal cities, the influence of O 3 ST was enhanced. The influence of O 3 SN was stronger in the northwestern HRB. Air temperature is the prevailing variable that influences the photochemical formation of ozone. A clear phase lag (7–34 days) of the baseline component between MDA8 O 3 and the atmospheric temperature was found in the HRB. Using multiple linear regression, the effect of temperature on ozone was removed. We estimated that the increase in ozone concentration in the HRB was mainly caused by the emission changes (79.4%), and the meteorological conditions made a small contribution (20.6%). This study suggests that reductions in volatile organic compounds (VOCs) will play an important role in further ozone pollution reduction in the HRB.