| In recent years,atmospheric fine particulate matter?PM2.5?had become the primary pollutants of urban air pollution problems and the most serious pollution was in Beijing area.Since China's reform and opening up,Beijing,as capital,political,and cultural center of China,that economy was on the high speed development at the same time air pollution problem was increasingly outstanding.In 2017,the frequency of smog in Beijing was still at a relatively high level.Especially in the fourth quarter?winter?,cold air activity was frequent and a total of 4 heavy pollution processes occurred.The PM2.5 concentration was as high as 500?g/m3.At home and abroad at present,most of the research was mainly around the pollution characteristics,composition and pollution source of PM2.5 in the air.However,a large number of activities time of the residents was mainly concentrated in the interior in daily life,so the study of indoor air pollution characteristics also had the vital significance.At the same time,polycyclic aromatic hydrocarbons?PAHs?as an important organic component of PM2.5,with teratogenic,carcinogenic,respectively,had serious harm on human health and the quality of atmospheric environment.The four typical regions of Beijing was main research areas,and collected four seasons?spring,summer,autumn,winter?atmospheric fine particulate matter in the air of different regional,mainly for the pollution characteristic research of fine particulate matter?PM2.5?concentration,organic/inorganic carbon?OC/EC?concentration and polycyclic aromatic hydrocarbons?PAHs?concentration,and had a health risk assessment of PAHs.Main conclusions:?1?The typical regional ambient air fine particulate matter?PM2.5?concentration range was in 7.63504.21?g/m3 and indoor air PM2.5 concentration range was in1.84488.86?g/m3.High concentrations of PM2.5 concentrations was mainly in the Z1?Fang-shan and Da-xing?and Z2?Dong-cheng and Chao-yang?sampling area as well as the autumn and winter,the highest standard ratio of 6.7 times and 6.5 times respectively,and the pollution was relatively serious.At the same time,correlation analysis showed that the ambient air on indoor air had a certain contribution rate of increasing concentration of PM2.5,and advised residents to minimize outdoor activity in heavy pollution weather.?2?The research and analysis showed that Beijing indoor and outdoor air fine particulate matter carbon?OC/EC?concentration and PM2.5 concentration had similar distribution characteristics,and Z1 sampling area?Fang-shan and Da-xing?indoor and outdoor air OC/EC had a heaviest pollution,especially the winter.Characteristics ratio method analysis showed that ambient air OC/EC mainly sources was from motor vehicle exhaust emissions,however,wood burning is also an important source in autumn and winter.At the same time,the mainly sources of indoor air came from vehicle exhaust emissions and gas combustion.?3?The typical regional indoor and outdoor air pollution characteristics of PAHs was the same as PM2.5 and OC/EC,and Z1 and Z2 sampling area pollution was more serious in autumn and winter.At the same time,according to the distribution of PAHs,indoor and outdoor air PAHs was mainly epipodium polycyclic aromatic hydrocarbons?4,5,and 6 ring?.Characteristics ratio method analysis showed that the indoor and outdoor air source of PAHs in different seasons was combustion source?motor vehicle exhaust emission?and coal,biomass burning,especially in autumn and winter.?4?The health risk assessment results showed that ambient air and indoor air PAHs total carcinogenic risk for adult was in 0.45×10-68.38×10-66 and 0.64×10-63.04×10-6,and the total carcinogenic risk for children was in 0.95×10-611.33×10-66 and 0.87×10-64.11×10-6,which had some potential risk of cancer but all belong to an acceptable range.Carcinogenic risk of carcinogenic PAHs for adults and children were significantly higher than the non-carcinogenic PAHs,and PAHs of carcinogenic risk of children was obviously higher than that of adults,mainly BaP and DBA.At the same time,ambient air PAHs carcinogenic risk was higher than that in indoor air,and because of the influence of the city heating,autumn and winter indoor and outdoor air PAHs potential carcinogenic risk was higher than that in spring and summer.?5?In general,the Beijing atmospheric fine particulate matter pollution situation was still serious,and ambient air pollution was more serious than indoor air condition,at the same time,autumn and winter indoor and outdoor air pollution was heavier,but controlled zone Z4?scenic area?all kinds of air pollutant concentration was at low levels in this study,and suggested that the general residents should have less unnecessary outdoor activities as far as possible in daily life,as well as keeping indoor clean,open smoke lampblack machine during cooking,at the same time reducing coal,wood,and biomass burning in rural areas in autumn and winter. |
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