The actual situation of two sand and dust weather processes with heavy pollution in Ulanqab City in 2021 was analyzed from the aspects of air quality,visibility,PM_(2.5)and PM_(10),and the causes of the sand and dust ...The actual situation of two sand and dust weather processes with heavy pollution in Ulanqab City in 2021 was analyzed from the aspects of air quality,visibility,PM_(2.5)and PM_(10),and the causes of the sand and dust weather with heavy pollution were discussed.The differences between the two processes in transport characteristics of sand and dust were studied,and the roles of high-and low-altitude weather systems and their impact on sand and dust transport were explored.展开更多
Hotan Prefecture is located at the southwestern edge of Taklimakan Desert, the world's largest shifting sand desert, of China. The desert is one of the main sources for frequent sand-dust weather events which stro...Hotan Prefecture is located at the southwestern edge of Taklimakan Desert, the world's largest shifting sand desert, of China. The desert is one of the main sources for frequent sand-dust weather events which strongly affect the air quality of Hotan Prefecture. Although this region is characterized by the highest annual mean PM_(10) concentration values that are routinely recorded by environmental monitoring stations across China, both this phenomenon and its underlying causes have not been adequately addressed in previous researches. Reliable pollutant PM_(10) data are currently retrieved using a tapered element oscillating microbalance(TEOM) 1400 a, a direct real-time monitor, while additional concentration values including for PM_(2.5), sulfur dioxide(SO_2), nitrogen dioxide(NO_2), carbon monoxide(CO) and ozone(O_3) have been collected in recent years by the Hotan Environmental Monitoring Station. Based on these data, this paper presents a comparison of the influences of different kinds of sand-dust weather events on PM10(or PM_(2.5)) as well as the concentrations of other gaseous pollutants in Hotan Prefecture. It is revealed that the highest monthly average PM10 concentrations are observed in the spring because of the frequent occurrence of three distinct kinds of sand-dust weather events at this time, including dust storms, blowing dust and floating dust. The floating dust makes the most significant contribution to PM_(10)(or PM_(2.5)) concentration in this region, a result that differs from eastern Chinese cities where the heaviest PM_(10) pollution occurs usually in winter and air pollution results from the excess emission of local anthropogenic pollutants. It is also shown that PM_(10) concentration varies within typical dust storms. PM_(10) concentrations vary among 20 dust storm events within Hotan Prefecture, and the hourly mean concentrations tend to sharply increase initially then slowly decreasing over time. Data collected from cities in eastern China show the opposite with the hourly mean PM_(10)(or PM_(2.5)) concentration tending to slowly increase then sharply decrease during heavy air pollution due to the excess emission of local anthropogenic pollutants. It is also found that the concentration of gaseous pollutants during sand-dust weather events tends to be lower than those cases under clear sky conditions. This indicates that these dust events effectively remove and rapidly diffuse gaseous pollutants. The analysis also shows that the concentration of SO_2 decreases gradually at the onset of all three kinds of sand-dust weather events because of rapidly increasing wind velocity and the development of favorable atmospheric conditions for diffusion. In contrast, changes in O_3 and NO_2 concentrations conformed to the opposite pattern during all three kinds of sand-dust weather events within this region, implying the inter transformation of these gas species during these events.展开更多
文摘The actual situation of two sand and dust weather processes with heavy pollution in Ulanqab City in 2021 was analyzed from the aspects of air quality,visibility,PM_(2.5)and PM_(10),and the causes of the sand and dust weather with heavy pollution were discussed.The differences between the two processes in transport characteristics of sand and dust were studied,and the roles of high-and low-altitude weather systems and their impact on sand and dust transport were explored.
基金supported by the National Key R&D Program of Chinagrant number 2018YFC1507701the Key Research and Development(R&D)Projects of Shanxi Province grant number 201803D31220the EDF programthe Belt and Road national greenhouse gas and pollutant co-control study grant number 2019-434。
基金supported by the National Natural Science Foundation of China(91644226)the National Key Research Project of China(2016YFA0602004)the Fundamental Research Funds of Chinese Academy of Meteorological Sciences(2017Y005)
文摘Hotan Prefecture is located at the southwestern edge of Taklimakan Desert, the world's largest shifting sand desert, of China. The desert is one of the main sources for frequent sand-dust weather events which strongly affect the air quality of Hotan Prefecture. Although this region is characterized by the highest annual mean PM_(10) concentration values that are routinely recorded by environmental monitoring stations across China, both this phenomenon and its underlying causes have not been adequately addressed in previous researches. Reliable pollutant PM_(10) data are currently retrieved using a tapered element oscillating microbalance(TEOM) 1400 a, a direct real-time monitor, while additional concentration values including for PM_(2.5), sulfur dioxide(SO_2), nitrogen dioxide(NO_2), carbon monoxide(CO) and ozone(O_3) have been collected in recent years by the Hotan Environmental Monitoring Station. Based on these data, this paper presents a comparison of the influences of different kinds of sand-dust weather events on PM10(or PM_(2.5)) as well as the concentrations of other gaseous pollutants in Hotan Prefecture. It is revealed that the highest monthly average PM10 concentrations are observed in the spring because of the frequent occurrence of three distinct kinds of sand-dust weather events at this time, including dust storms, blowing dust and floating dust. The floating dust makes the most significant contribution to PM_(10)(or PM_(2.5)) concentration in this region, a result that differs from eastern Chinese cities where the heaviest PM_(10) pollution occurs usually in winter and air pollution results from the excess emission of local anthropogenic pollutants. It is also shown that PM_(10) concentration varies within typical dust storms. PM_(10) concentrations vary among 20 dust storm events within Hotan Prefecture, and the hourly mean concentrations tend to sharply increase initially then slowly decreasing over time. Data collected from cities in eastern China show the opposite with the hourly mean PM_(10)(or PM_(2.5)) concentration tending to slowly increase then sharply decrease during heavy air pollution due to the excess emission of local anthropogenic pollutants. It is also found that the concentration of gaseous pollutants during sand-dust weather events tends to be lower than those cases under clear sky conditions. This indicates that these dust events effectively remove and rapidly diffuse gaseous pollutants. The analysis also shows that the concentration of SO_2 decreases gradually at the onset of all three kinds of sand-dust weather events because of rapidly increasing wind velocity and the development of favorable atmospheric conditions for diffusion. In contrast, changes in O_3 and NO_2 concentrations conformed to the opposite pattern during all three kinds of sand-dust weather events within this region, implying the inter transformation of these gas species during these events.
