Study On Source And Control Technology Of Indoor Fine Particulate Matter

With the long heating season in Northeast China,the combustion of coal and fossil fuel will generate a large number of fine particles,which will cause serious urban environmental pollution and also have a huge impact on people's living environment.Outdoor PM_2.5will carry heavy metals and polycyclic aromatic hydrocarbons into the room through personnel carrying,door and window penetration and other ways.Indoor smoking,cooking and other activities will also generate a large number of PM_2.5,and indoor air quality will face internal and external problems.With the popularity of air purifiers in recent years,the use of air purifiers has gradually become an effective means to improve indoor air quality.Residential buildings are closely related to people's life,so it is particularly important to study PM_2.5and its attached harmful substances in residential buildings.This paper selected four representative houses in Changchun city and conducted a multi-angle study.Continuous monitoring for a period of one year;Monitoring the vertical distribution of indoor and outdoor particulate matter in high-rise residential buildings during the heating season;Monitoring and analyzing the change trend of particulate matter from different indoor sources under different purification methods;The indoor purifier was detected to absorb pollutants in particulate matter and the human health risk was evaluated.The conclusion is as follows:1.The indoor and outdoor PM_2.5concentration has significant difference in different seasons and months.The indoor and outdoor PM_2.5concentration in winter and spring was significantly higher than that in summer and autumn,and the indoor and outdoor PM_2.5concentration fluctuates significantly in winter and spring.There was a significant correlation between indoor PM_2.5concentration and outdoor PM_2.5concentration.The contribution value of outdoor PM_2.5in winter and spring was higher than that in summer and autumn,but the contribution rate was significantly lower than that in summer and autumn,which was related to the outdoor PM_2.5concentration in different seasons and the number of indoor and outdoor air changes.2.In the heating season,the indoor and outdoor PM_2.5concentration of high-rise residential buildings was high,and the outdoor concentration was in the pollution state for most of the time,and the indoor concentration was in the pollution state for some time.Indoor heavy metal pollution was serious,and the distribution of heavy metal elements on different floors was different.The concentration of metal elements on lower floors was higher than that on higher floors,and the concentration of different elements was also significantly different.The enrichment factors of As,Cd,Cu and Pb in 11 metal elements were more than 10,which indicated that these four elements were seriously affected by human sources,and the enrichment factors of the other seven metal elements were less than 10,which indicated that their sources may be natural sources.Principal component analysis showed that the main sources of indoor metal elements in high-rise residential buildings were divided into four principal components,including 31.441%of coal combustion,21.595%of automobile emission and transportation,13.427%of soil dust,particulate matter from agricultural production and air dust,12.614%of metallurgical,chemical and ore mining.3.Cigarette,burning incense and cooking oil smoke were the main sources of indoor PM_2.5pollution.Cooking oil smoke has the largest contribution,while cigarette contribution was relatively small.The contribution of the same pollution source to indoor PM_2.5was significantly different in winter and summer.The indoor PM_2.5concentration in winter was significantly higher than that in summer,which was related to the different outdoor PM_2.5concentration values in different seasons.When the air purifier was involved in the purification process,the average and maximum values of indoor PM_2.5concentration were significantly reduced.In summer,natural ventilation&purifier was the best way to purify incense and oil fume,and opening purifier was the best way to purify cigarette.In winter,opening the purifier alone was the best way to control PM_2.5.Three kinds of indoor pollution sources PM_2.5will threaten people's health.Opening air purifier can reduce people's health damage by 43.47%?86.46%.The intervention effect of air purifier on indoor PM_2.5control and human health is positive.4.Among the particles absorbed by the air purifier,the total concentration of 8heavy metals was 771.27mg/kg in the heating season and 441.10mg/kg in the non-heating season.In the heating season,the concentration sequence was Pb>Zn>Cu>Mn>Ni>As>Cr>Cd,and in the non-heating season was Zn>Pb>Mn>Ni>Cu>Cr>As>Cd.The carcinogenic and non-carcinogenic exposure of heavy metals in heating season was higher than that in non-heating season,and the exposure of children was higher than that of adults.Eight kinds of heavy metal elements would cause non-carcinogenic risk to children,and four kinds of carcinogenic heavy metals would cause carcinogenic risk to adults and children.The total concentration of 16 PAHs in heating season is 106.69?g/kg,the toxic equivalent concentration is 16.37?g/kg,the non-heating season is 68.72?g/kg,and the toxic equivalent is 9.20?g/kg.Among them,the contribution of PAHs of 4-ring to the total concentration was the largest,that of PAHs of 5-ring and 6-ring were larger,and that of PAHs of 2-ring and 3-ring were lower.PAHs would cause high carcinogenic risk to adults and children in heating season,and would cause potential carcinogenic risk in non-heating season.