Abstract:
The spatial and temporal distribution characteristics of PM
2.5 were analyzed at the township scales with the monitoring data from 261 automatic air quality monitoring stations of Shijiazhuang City in 2018, using the spatial analysis method of geographic information systems (GIS). The correlation characteristics between PM
2.5 and its precursors (SO
2, NO
2) were also discussed. The results showed that the annual concentration of PM
2.5 in 261 townships was 41-112 μg/m
3 in 2018, which exceeded the secondary standard limit of
Ambient Air Quality Standards (GB 3095-2012). The concentration of PM
2.5 was generally lower in the mountainous area with higher terrain in the northwest than that in the plain area in the southeast, and it was lower in the main urban area than that in the surrounding counties (cities and districts). In respect of seasonal variation, the average concentrations of PM
2.5 in Shijiazhuang City was the highest in winter and lowest in summer. Monthly average concentrations of PM
2.5 showed that it was from January to March and from November to December that the data of PM
2.5 were higher than those of the rest months of the year, August was the month that with the lowest monthly average concentration. The concentration of PM
2.5 was significantly positively correlated with the concentration of both SO
2 and NO
2 in the observation period. The degree of the correlation was the weakest in summer and the strongest in winter, and the more serious the pollution was, the more significant the degree of regional correlation was.