Analysis of ozone pollution characteristics and meteorological parameters in Nanyang City from 2015 to 2019

Based on the hourly observation data of six conventional pollution parameters provided by five state-controlled environmental monitoring sites in Nanyang City from 2015 to 2019, and combined with the surface meteorological elements data of Nanyang Station, the national benchmark station, the temporal and spatial distribution characteristics of ozone pollution and the influence of meteorological factors were investigated. The results showed that the ozone pollution in Nanyang City became serious from 2015 to 2019, and the average daily maximum 8 h sliding concentration (MDA8) of O₃ increased from 145 μg/m³ in 2015 to 181 μg/m³ in 2019, with an increase of more than 25%. O₃ pollution displayed a distinct seasonality, where the maximum values occurred in summer. As for spatial distribution, the O₃ pollution presented obvious block distribution characteristics, and its high value appeared in the central area of the city. Meteorological conditions were important factors affecting the concentration of O₃ in Nanyang City. Under high temperature, low humidity and high visibility conditions, it was easy to form serious ozone pollution. With the increase of wind speed, the O₃ concentration increased first and then decreased. In June 2019, the O₃ pollution in Nanyang City was serious, and the O₃ exceedance rate was more than 63%. During this period, there were three ozone pollution processes. The pollution events were related to favorable meteorological conditions and strong pollution emission intensity.