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To evaluate the environmental effectiveness of the control measures for atmospheric pollution in Shijiazhuang of China, a large-scale controlling experiment for emission sources of atmospheric pollutants (i.e., a temporary emission control action, TECA) was designed and implemented during November 1, 2016 to January 9, 2017. Under the unfavorably meteorological conditions, the mean concentrations of PM2.5, PM10, SO2, NO2, and chemical species (Si, Al, Ca2+, Mg2+) in PM2.5 during the control action and heating period (CAHP) still decreased by 15 %, 26 %, 5 %, 19 %, 30.3 %, 4.5 %, 47.0 % and 45.2 %, respectively, compared to the no control action and heating period (NCAHP); indicating that the control measures of atmospheric pollution in Shijiazhuang were effective and was in a right direction. Overall, the effects of control measures in suburbs were better than those in urban area, especially for the control effects of particulate matters sources. The control effects for emission sources of carbon monoxide (CO) were not apparent during the TECA period, especially in suburbs, which is likely due to the increasing usage of domestic coal in suburbs along with the temperature decreasing. The results of PMF analysis showed that crustal dust, secondary sources, vehicle emissions, coal combustion and industrial emissions were major PM2.5 sources. Compared to the whole year, the contributions of coal combustion to PM2.5 increased significantly during the CAHP and after control action (ACA); while the contribution proportions of crustal dust and vehicle emissions to PM2.5 decreased apparently during the CAHP. The contribution concentrations and proportions of crustal dust and vehicle emissions to PM2.5 during the CAHP also decreased significantly compared to ACA. The pollutant's emission sources during the CAHP were in effective control, especially for crustal dust and vehicles. While the necessary coal heating for cold winter and the unfavorably meteorological conditions had an offset effect on the control measures for emission sources to some extent. Meanwhile, our results also illustrated that the discharge of pollutants was still enormous even under such strict control measures. The backward trajectory and potential source contribution function (PSCF) analysis in the light of atmospheric pollutants suggested that the potential sources-areas mainly concentrated in surrounding regions of Shijiazhuang, i.e., south of Hebei, north of Henan and Shanxi. The regional nature of the atmospheric pollution in Northern China Plain revealed that there is an urgent need for making cross-boundary control policy except for local control-measures given the high background level of pollutants. The TECA is an important practical exercise but it can't be advocated as the normalized control measures for atmospheric pollution in China. The direct cause of atmospheric pollution in China is the emission of pollutants exceeds the air environment's self-purification capacity, and the essential reason is unreasonable and unhealthy pattern for economic development of China. |
