Characterization of the Air Quality Index for Wuhu and Bengbu Cities, China

Abstract

From 2015–2017, the atmospheric PM10, SO2, NO2, CO, and O3 in Wuhu and Bengbu were investigated in this study. In addition, the AQI values and seasonal variations in six AQI classes and corresponding primary pollutants were also studied. In Wuhu, the daily AQI ranged from 23 to 298 in 2015, from 33 to 290 in 2016, and from 34 to 278 in 2017, and the corresponding mean values were 81, 80 and 90, respectively. In Bengbu, the daily AQI ranged from 23 to 288 in 2015, from 32 to 286 in 2016, and from 27 to 500 in 2017, and the corresponding mean values were 88, 89 and 97, respectively. During the three-year study, in Wuhu, the mean proportion of levels with Grade I, II, III, IV, V and VI were 9.33%, 69.3%, 18.3%, 3.00%, 0% and 0% in spring; were 35.0%, 55.0%, 7.00%, 3.00%, 0% and 0% in summer; were 13.6%, 65.0%, 18.0%, 3.33%, 0% and 0% in fall, and were 5.33%, 48.7%, 30.7%, 9.67%, 5.67% and 0% in winter. In Bengbu, the mean proportion of levels with Grade I, II, III, IV, V and VI were 3.00%, 64.0%, 30.3%, 2.67%, 0.333% and 0.333% in spring; were 19.3%, 68.7%, 11.3%, 0.667%, 0% and 0% in summer; were 20.7%, 56.3%, 17.3%, 4.67%, 1.00% and 0% in fall, and were 9.67%, 36.7%, 31.0%, 32.0%, 5.67% and 0% in winter. Generally, the air quality in the two cities were in the following order: summer > fall > spring > winter. AQI ranged between 101–150, where in Wuhu, the primary air pollutants were PM2.5 and NO2 in 2015; were PM2.5, NO2 and O3 in 2016, and were PM2.5, PM10, NO2 and O3 in 2017. In Bengbu, PM2.5, PM10 and O3 were the primary air pollutants during the three years. When AQIs ranged between 151 and 200, in Wuhu, the primary air pollutant was PM2.5 in 2015; were PM2.5 and PM10 in 2016, and were PM2.5, PM10, and O3 in 2017. In Bengbu, the primary air pollutant was PM2.5 in 2015 and 2016 and comprised PM2.5 and O3 in 2017. When AQIs were between 201 and 300, in Wuhu, PM2.5 was the primary air pollutant in 2015–2017. In Bengbu, the primary air pollutant was PM2.5 in 2015 and 2016 and comprised PM2.5 and PM10 in 2017. When the AQI ranged between 301–500, which did not occur in Wuhu from 2015–2017 or in Bengbu during 2015–2016, PM2.5 was as the primary air pollutant in Bengbu in 2017. When the AQI can be analyzed in more detail, the control strategies for air pollution will be more precise.