Impacts of Agricultural Soil NOx Emissions on O3 Over Mainland China

Abstract

AbstractRegional ozone (O3) pollution has currently become an urgent air pollution problem in China. Nitrogen oxides (NOX) are key precursor pollutants for O3 formation. However, pollution control policies have generally neglected or simplified the impacts of soil NOX emissions in rural regions. This study aims to evaluate the effect of soil NOX emissions on O3 in agricultural areas of China based on high‐resolution soil NOX emission inventory and the WRF‐Chem air quality model. We first validate the simulation result of the O3 concentration with surface O3 observations over China using the selected optimal physicochemical scheme. After that, four scenarios are designed to simulate and analyze the regional sensitivity of O3 to soil NOX emissions and to quantify the effect of soil NOX emissions on O3 concentration. The results indicate that as soil NOX emissions increase, the overall spatial pattern does not change notably over mainland China, but the O3 concentration increases remarkably in the northwest and northeast of China. Additionally, we discover that changes of O3 concentration across mainland China differ substantially among regions. Our results highlight the effect of soil NOX emissions on air quality in agricultural areas. The control of O3 pollution in China should take into account the comprehensive consequences of various emission sources, as well as their regional differences.