PM_2.5/PM₁₀ Ratios in Eight Economic Regions and Their Relationship with Meteorology in China

Abstract

China is suffering severe ambient air pollution in recent decades and particulate matter (PM) has become the major pollutant, especially for PM2.5 and PM10, which have highly raised scholars and policy-makers’ attention in last few years. The existing research has focused on the characteristics of PM2.5 and PM10, respectively, or analyzed the correlation between the two pollutants, while the ratio of PM2.5 to PM10 has been taken less consideration. In this study, daily mean PM2.5 and PM10 mass concentrations in 31 provincial capitals from 2014 to 2016 were used to present the temporal variations and spatial distribution of PM2.5/PM10 ratios among eight economic regions. And then, statistical method and correlation analysis were adopted to investigate the relationship between the ratios and AQI, the rate of change on the ratios, and the impact of meteorological parameters on the ratios. The results indicated that PM2.5/PM10 ratios showed an increasing trend from northwest to southeast due to different economic development and industrial types. The highest values were observed in winter among all regions, and the ratios on weekends were higher than that of on weekdays in most of the regions. Besides, domestic heating in northern China had a significant contribution to the ratios. Moreover, ratios had less changes, and the rate of change was stable in summer. As for air quality, the higher the ratio, the larger the possibility of high AQI so that the air pollution will be more severe. In terms of meteorological factors, the results demonstrated that relative humidity, precipitation, and pressure were the most important factors and had significantly positive impacts, while sunshine duration, temperature, and wind speed had negative effects on the ratios. The findings could identify the pollution sources among PM10 and be helpful for making regulation locally to reduce emission which considers anthropogenic sources and meteorological diffusion simultaneously.

Characterization of Inhalable Ground-Level Ambient Particulate Matter in Dhaka City, Bangladesh

“…It indicates that, monsoon seasons had the highest rainfall rate which forced to drop the concentration of particles. Due to rainfall in monsoon season particulate matter may deposit in the ground though there is a chance to increase the PM concentration by drying up during the high summer temperature after rain [35]. Similar observations in Bangladesh were observed, the PM pollutants resulted negative correlationwith rainfall, atmospheric temperature during the study period [35].…”

“…Brick kilns and vehicles emission are the main sources of fine particles (PM 2.5 ) where coarse particles are assumed to be generated from mechanical processes [33]. The most considerable reasons for the higher ratio of PM 2.5 in the winter season are , and organics [29,32,34].…”

Spatial distribution and temporal variation of atmospheric pollution in the South Gobi Desert, China, during 2016–2019

“…The Tengger Desert may directly affect the atmosphere of Wuwei, Zhongwei, and Wuzhong, where PM 10 concentrations exceed 127 μg/m 3 . Elevated levels of PM 2.5 not only in the study cities, but in the majority of cities of the northern part of China, are the result of coal and biomass burning for residential heating (Qiu et al 2016;Zhao et al 2019). Besides, the less amount of precipitations, the lower air temperature, and low height of planetary boundary layer (PBL) as well as the feebler winds in winter may worsen environmental pollution still greater (Xu et al 2016).…”

“…However, PM 2.5 /PM 10 ratio varies depending on time and space, the nature of land management and emissions. PM 2.5 and PM 10 are closely related, since PM 2.5 contributes a lot to the total PM 10 content in the atmosphere (Naser et al 2008;Zhao et al 2019). The size of atmospheric particulate matter is important as a determinant factor of how long the particles remain in atmosphere and where they subsequently sediment in human respiratory passages.…”

“…For the last several decades, China experienced a rapid urbanization and industrialization, which influenced heavily on ecological situation in the country as a result of which air pollution in cities became one of key national problems (Wang et al 2014;Chen et al 2016;Leung et al 2018;Zhao et al 2019). Development of many branches of industry resulted in huge atmospheric emissions of such pollutants as particulate matter (PM) (PM 2.5 (particles with aerodynamic diameter ≤ 2.5 μm) and PM 10 (particles with aerodynamic diameter ≤ 10 μm)) and gas pollutants (sulfur dioxide (SO 2 ), nitrogen dioxide (NO 2 ), and carbon monoxide (CO)).…”