Temporal‐spatial variations of air pollutants in Lanzhou, Gansu Province, China, during the spring–summer periods, 2014–2016

Abstract

AbstractIn this article, we analyzed the mass concentrations of particulate matter 2.5 micrometers (µm) or less in size (PM2.5), particulate matter 10 µm or less in size (PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), and ozone (O3) in Lanzhou, the capital of Gansu province, China. We analyzed monitoring data collected from five air quality monitoring stations during the spring–summer period from 2014 to 2016. Our comparison of contaminant concentrations and average diurnal, daily, monthly, and annual concentrations revealed that the average concentrations of PM2.5 and PM10 amounted to 128.57 and 46.4 micrograms per cubic meters (µg/m3), respectively, exceeding the Chinese National Ambient Air Quality Standard (NAAQS). We used the Pearson correlation coefficient to establish connections between particulate matter and gaseous pollutants. The results show significant differences in the concentration levels of airborne pollutants. The Pearson correlation coefficient between PM2.5 and PM10 had the highest coefficient of r = 0.842. A correlation between the two particulate matter sizes (PM2.5 and PM10) and SO2 was PM2.5 and SO2 r = 0.313; PM10 and SO2 r = 0.279; and CO and the two particulate matter sizes, PM2.5 and CO r = 0.304; and PM10 and CO r = 0.203. The average monthly ratio for the study months of PM2.5 to PM10 was 0.361. In addition, we used the hybrid single particle Lagrangian integrated trajectory model for tracking sources and pathways of the air pollutants in Lanzhou.