[Characteristic of Surface Ozone and Meteorological Parameters Analysis in Anyang City]

This study uses the national ambient air quality station data of Anyang City from 2014 to 2017 to analyze the characteristics and variation rules of ozone (O₃) in different functional zones (urban, suburban, and industrial), and also studies meteorological influencing factors and potential source distributions of O₃ pollution. The results showed that the O₃ concentration in Anyang increased significantly between 2014 and 2017, whereby pollution started to advance from 2015 and the earliest occurrence of an O₃ pollution episode was in April 2017. The 90^th percentile and average concentrations of O₃ in the industrial zone increased at faster rates (average annual growth of 16.0 μg·m^-3 and 13.0 μg·m^-3, respectively) than of those in the urban and suburban zones. The O₃ concentrations at the suburban site showed the fastest increase of all zones at the 5^th percentile (average annual growth of 13.2 μg·m^-3). The monthly variation in O₃ concentrations in Anyang showed an "M" pattern that varied spatially depending on the zone. Temperature played a leading role in O₃ concentrations; air temperatures >23℃, relative humidity <58%, and a wind speed of 5 m·s^-1 in a south-southwesterly direction were closely related to the occurrence of high O₃ concentrations. Potential sources of O₃ in different seasons were significantly different, and mainly distributed in southern Hebei, northern Hubei, and northern Shenyang in summer. The first heavy O₃ pollution day in the studied period was in May 2017, at which time the highest O₃ concentration was found in the industrial zone (up to 405 μg·m^-3). This heavy O₃ pollution episode was related to the continuous high temperature that was caused by the transfer of a dry, hot air mass in western China.