Cold fronts transport features of North China pollutant over Jiangsu Province, China

Özet

An air pollution process in Jiangsu Province on December 22–23, 2016 is discussed by analyzing various dataset, including the meteorological observation data, the reanalysis data from National Centers for EnvironmentalPrediction (NCEP), the Air Quality Index (AQI), the PM2.5 and PM10 concentrations data, and the airflowbackward trajectory model of National Oceanic and Atmospheric Administration (NOAA). The results show thatthe air pollution episode was under the background of a medium cold front from the west of the Hetao area, andcaused by regional transport of pollutants from North China. The primary pollutant was PM2.5 and PM10. ThePM2.5 and PM10 concentrations increase significantly 4–6 h after the cold front passing and reached the peak in13–24 h. The obvious lag phenomena of the rising period and the peak-moment of PM2.5 and PM10 concentrations were found at the Suzhou, Huai'an, Taizhou and Xuzhou stations, and the maximum of 3h-allobaric,the maximum and average values of the wind speed near the ground were larger one by one at the four stationsrespectively in the northwestern Jiangsu, north-central Jiangsu, along with the Yangtze river Jiangsu, andsoutheastern Jiangsu. The period of middle –heave level pollution in Suzhou was 7–9 h later than in Huai'an andTaizhou, and was 24 h later than in Xuzhou, because of the lower PM2.5 and PM10 concentrations at earlyDecember 21, the delay of pollutants from upstream, and the larger wind speed from the boundary layer to thesurface in southeastern Jiangsu. WRF-Chem model can well reveal the pollutant transport process. The highvalue zone has a close relationship with the position of cold front. At 1200 LST on December 22, the cold frontreached Xuzhou accompanied by high PM2.5 concentration. At 1400 LST on December 22, the cold front advanced to Huai'an. The high PM2.5 concentration zone moved south alongside the cold front and covered Xuzhouand Huai'an. Suzhou, far away from the upstream, was less vulnerable to pollutant transport. The high-value didnot fell until the northwest wind shifted to the north wind. The backward trajectory analysis of air pollution alsoindicated that regional transport of pollutants from North China led to the middle –heave level pollutionweather.