Abstract:

Based on air quality data at five national environmental monitoring points released on the national urban air quality real-time release platform of China environmental monitoring station and meteorological data observed at a national weather station in Karamay from 2015 to 2017, we analyzed the spatiotemporal variation of PM_2.5 concentration in four districts of Karamay and the impact of meteorological conditions.The results showed that PM_2.5 concentration is the highest in January, February, and December, followed by March and November in Karamay from 2015 to 2017.The highest PM_2.5 level is observed at Dushanzi during February each year, with a maximum monthly mean value of 134 μg·m^-3 in February 2016, which is 2.8 times higher than the national PM_2.5 standard value and reaches a moderate pollution level.In terms of seasonal variation, PM_2.5 concentration in Karamay exhibits obvious wave crest and trough.The highest PM_2.5 values occur in winter and then in spring in all districts, and have different characteristics in summer and autumn in different districts.PM_2.5 concentration during the domestic heating period is higher than that in the non-heating period.On average, PM_2.5 concentration is higher in the Dushanzi area, followed by the Baikali beach area, Karamay area, and Wuerhe area in order.PM_2.5 concentration has a significantly positive correlation with air pressure and relative humidity and has a negative correlation with wind speed, air temperature, and wind direction.The negative correlations with the air temperature and wind direction are especially significant.

Key words: PM_2.5 concentration, Spatiotemporal variation, Meteorological conditions