Feature analysis on air quality in the main urban area of Nanchong City in 2015–2018

Abstract

This study evaluates the air quality in Nanchong City in 2015–2018 based on automatic monitoring data and meteorological data in the main urban area. Results show that overall air quality in the main urban area of Nanchong was standard and improved from 2015 to 2018. SO2, NO2, and CO had slight influences on air quality in the study area, whereas excessive annual average PM2.5 and increasing O3 concentration challenged the air quality. The monthly average mass concentrations of particulate matters (PM2.5 and PM10), NO2, and CO generally presented a “U-shaped” distribution pattern while O3 showed the opposite. The diurnal variation of PM, NO2, and CO has two peaks related to the morning and evening rush hours. Vehicle exhaust is the main source of local pollution. Over-standard PM2.5 can significantly inhibit O3 production while O3 can easily promote the secondary generation of PM2.5 due to its strong oxidization. PM2.5 emission should be controlled strictly in winter, while in summer, the sources of O3 should be controlled vigorously. Air pollution is comprehensive and complicated and is influenced by various factors, mainly meteorological and human factors. Measures such as artificial rainfall should be included at the appropriate time to cope with adverse meteorological conditions when heavy pollution occurs in winter.