Abstract
HOx radicals play a key role in tropospheric ozone (O3) formation, and understanding their behavior is essential for controlling the O3 levels. While observation studies in urban areas have progressed, knowledge remains limited in suburban areas where anthropogenic and natural sources are mixed. This study used data from AQUAS-Kyoto 2018 and CMAQ modeling to evaluate the air quality in suburban areas. In the first half of the observation period, clean air was dominant, and OH reactivity was largely driven by biogenic emissions. On the other hand, in the latter half, air from urban areas increased the OH reactivity, likely due to transported anthropogenic compounds. CMAQ modeling generally reproduced the BVOCs and O3 concentrations throughout the observation period, but tended to underestimate anthropogenic substances, and in the analysis of the O3 production regime, the model showed an opposite tendency, with the VOC regime in the first half and the NOx regime in the second half being stronger than the observed results. These results indicated that the air quality is complex in suburban areas, which are influenced by various sources, and that differences in the O3 precursor concentrations and sensitivity analysis results are likely to occur, providing insight for improving the air quality and chemical transport model accuracy.
