[Research on the Pollution Characteristics and Causality of Haze-sand Air Pollution in Beijing in Spring].
Huan Jing Ke Xue
; 40(6): 2582-2594, 2019 Jun 08.
Article
en Zh
| MEDLINE
| ID: mdl-31854649
ABSTRACT
From May 3 to 5, 2017, a special heavy pollution event occurred in Beijing. The meteorological conditions associated with the heavy pollution were relatively special, so the pollution forms and causes were studied. The general characteristics of this pollution event were obtained based on data from 35 environmental monitoring stations in Beijing. Matching characteristics of PM10 and PM2.5 concentrations with ground wind field data from automatic weather stations closest to the environmental monitoring stations were analyzed. By using MODIS and CALIPSO data, the spatial distribution in the horizontal and vertical directions was obtained, and the transport paths and pollutant categories of the pollution were elucidated. The causes of the pollution were analyzed by using ECMWF ERA-Interim data and Wind Profiler radar data. It was hoped that the special morphological characteristics and influencing factors of the pollution could be obtained by means of ground-space monitoring technology combined with meteorological conditions. The results showed that pollution characteristics and constraints could be better reflected by stereo observations and comprehensive analyses based on the above multi-source data. The pollution started abruptly and dropped sharply, and the pollution process lasted for about 30 hours. The whole process was divided into the following three stagesthe first half, intermittent period, and second half. The concentrations of PM10 and PM2.5 were high throughout the whole process, reaching to 600-1000 µg·m-3 and 200-700 µg·m-3, respectively. The causes of pollution in the first half and second half and the resulting PM10 and PM2.5 concentrations were different in terms of the spatial distribution. In the first half, the dominant wind direction was northwest wind, and the wind speed was small. The spatial difference of PM10 concentrations was also small, with concentrations more than 800 µg·m-3; meanwhile, the spatial difference of PM2.5 concentrations was great. The concentration of PM2.5 was high in the south and urban areas, reaching to 600-700 µg·m-3, and it was low in other places, reaching to 350-500 µg·m-3. During the intermission, the wind direction in the lower layer shifted from northwest wind to south wind, and the upper layer maintained northwest wind. The concentration of PM10 in the south and urban area decreased obviously to 650 µg·m-3, and the concentration of PM10 in the north remained at 800 µg·m-3. At this time, the concentration of PM2.5 in the north even dropped to 200 µg·m-3. The dominant wind returned to northwest wind in the latter half, and the wind speed increased sharply. At this time, the spatial difference of PM2.5 concentrations was small and the concentration of PM2.5 at the same station was less than that in the former half, ranging from 250 to 500 µg·m-3. The PM10 concentrations returned to the level of 800 µg·m-3. The pollution process involved mixed pollution consisting of haze and sand. Under the influence of westerly winds, the main contribution to Beijing pollution was dust-type PM10, while under southerly flows, the contribution to Beijing pollution was not only dust, but also PM2.5. Heavy pollution was accompanied by high wind speeds. The vertical motion of the atmosphere converged at an altitude of about 2-3 km, which resulted in the accumulation of pollutants at this altitude.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Tipo de estudio:
Etiology_studies
Idioma:
Zh
Revista:
Huan Jing Ke Xue
Año:
2019
Tipo del documento:
Article
País de afiliación:
China