Severe air pollution with visibility deterioration has long been a focus in the North China Plain(NCP).In this study,concentration and light extinction analysis of PM_(2.5)chemical components were carried out from 201...Severe air pollution with visibility deterioration has long been a focus in the North China Plain(NCP).In this study,concentration and light extinction analysis of PM_(2.5)chemical components were carried out from 2014 to 2017 to study the pollution characteristics in Baoding,a case city of the NCP.The annual average concentration of total PM_(2.5)components showed a declining trend,decreasing by 11μg m^(−3)(water-soluble inorganic ions),23μg m^(−3)(carbonaceous aerosols),and 1796 ng m^(−3)(inorganic elements).Contributing 82.9%to the concentration of total ions,the dominant components,NH 4+,NO 3−,and SO_(4)^(2−)became the main pollutants in PM_(2.5)pollution.Based on the IMPROVE algorithm,the average reconstructed PM_(2.5)mass concentration was 93±69μg m^(−3)during the observation period.Meanwhile,the light extinction coefficients were 373.8±233.6 M^(m−1),405.3±300.1M^(m−1),554.3±378.2M^(m−1)and 1005.2±750.3M^(m−1),in spring,summer,autumn,and winter,respectively.Ammonium sulfate,ammonium nitrate,and organic matter were the largest contributors to light extinction,accounting for a total of 55%–77%in the four seasons.The b sca(light scattering by particles and gases)reconstructed from PM_(2.5)components(Rb_(sca))and the b sca converted from visibility(Vb_(sca))were compared to evaluate the performance of the IMPROVE algorithm,revealing a high correlation coefficient of 0.84.The high values of Vb_(sca)were underestimated while the low values were overestimated,as determined through comparison with the one-to-ne line.Especially,when Rb_(sca)>1123M^(m−1)(corresponding to<2.0 km,approximately),Vb_(sca)was underestimated by 17.6%.PM_(2.5)mass concentration and relative humidity also had an impact on the estimation.展开更多
基金supported by the National Key Research and Development Program of China grant number 2016YFC0202001the Chinese Academy of Sciences Strategic Priority Research Program grant number XDA23020301+1 种基金the National Natural Science Foundation of China grant numbers 41375036 and 91644226the National Key Research and Development Program of China grant number2018YFC0214002。
文摘Severe air pollution with visibility deterioration has long been a focus in the North China Plain(NCP).In this study,concentration and light extinction analysis of PM_(2.5)chemical components were carried out from 2014 to 2017 to study the pollution characteristics in Baoding,a case city of the NCP.The annual average concentration of total PM_(2.5)components showed a declining trend,decreasing by 11μg m^(−3)(water-soluble inorganic ions),23μg m^(−3)(carbonaceous aerosols),and 1796 ng m^(−3)(inorganic elements).Contributing 82.9%to the concentration of total ions,the dominant components,NH 4+,NO 3−,and SO_(4)^(2−)became the main pollutants in PM_(2.5)pollution.Based on the IMPROVE algorithm,the average reconstructed PM_(2.5)mass concentration was 93±69μg m^(−3)during the observation period.Meanwhile,the light extinction coefficients were 373.8±233.6 M^(m−1),405.3±300.1M^(m−1),554.3±378.2M^(m−1)and 1005.2±750.3M^(m−1),in spring,summer,autumn,and winter,respectively.Ammonium sulfate,ammonium nitrate,and organic matter were the largest contributors to light extinction,accounting for a total of 55%–77%in the four seasons.The b sca(light scattering by particles and gases)reconstructed from PM_(2.5)components(Rb_(sca))and the b sca converted from visibility(Vb_(sca))were compared to evaluate the performance of the IMPROVE algorithm,revealing a high correlation coefficient of 0.84.The high values of Vb_(sca)were underestimated while the low values were overestimated,as determined through comparison with the one-to-ne line.Especially,when Rb_(sca)>1123M^(m−1)(corresponding to<2.0 km,approximately),Vb_(sca)was underestimated by 17.6%.PM_(2.5)mass concentration and relative humidity also had an impact on the estimation.
