The Relationship Between Indoor And Outdoor Particulate Matter And The Health Risk Assessment Based On Chemical Components And Source Apportionment

Epidemiological studies indicated that ambient particulate matter was associated with negative human health effects. Nowadays, people spend most of their time in indoor environments. It is important to investigate the relationship between indoor and outdoor particulate matter, the sources of particulate matter, and the health risk when people expose to these particle matter. This study was conducted in an elderly community during summer-autumn (from August19th to September24th) and winter (from November11st to December18th). Four kinds of PM10filter samples for personal exposure, residential indoor, residential outdoor and community were collected. Inorganic elements (crustal and metal elements), water-soluble ions (NO3’ and SO42-), carbon materials (OC and EC) and polycyclic aromatic hydrocarbons (PAHs) on these filter samples were analyzed. This study investigated the relationship between residential indoor and outdoor PMio, the sources of personal exposed PM10and the health risk for the elderly participants who exposed to PM10.The methods and results of this study were listed as follows.(1) Infiltration factors of indoor-outdoor particulate matter. Based on the chemical components of residential indoor and outdoor PM10, the infiltration factor of indoor-outdoor particulate matters was analyzed using microscopic mixture model. The results showed that the infiltration factor of residential indoor-outdoor particulate matter was0.74±0.31(mean±tandard deviation) in summer-autumn and0.44±0.22in winter. In summer-autumn, natural ventilations was one of the main ventilation modes for elderly participants caused by opening windows. This led to a large amount of PM10infiltrated from residential outdoor environments to residential indoor environments. In winter, the residential outdoor contributions to indoor PM10had no significant difference from those in summer-autumn (p>0.05). The personal exposed PM10of ambient origin has no significant seasonal difference (p>0.05). It is indicated that outdoor contribution of particulate matter to the indoor environments and the personal exposed particulate matter of ambient origin were similar in summer-autumen with those in winter.(2) Source apportionmen of particulate matter. The ambient and indoor sources of residential outdoor/community PM10and personal exposure/indoor PM10were analyzed by positive matrix factorization (PMF) receptor model. The results showed that the ambient sources included secondary sulfate and nitrate, soil, cement and metallurgy, coal and biomass combustion, and vehicle emissions, and the indoor sources included indoor dust, paint pigment, and environmental tobacco smoke (ETS) and cooking.(3) Infiltrtion fctors of particulate matter contributed from different ambient sources. Based on the sources of residential indoor and outdoor PM10, the infiltrtion fctors of particulate matter contributed from different ambient sources were analyzed. The infiltration factor of residential indooroutdoor PM10was0.73±0.32in summer-autumn and0.48±0.24in winter. It is similar with the infiltration factor calculated based on chemical components. The infiltration factors of PM10contributed from coal and biomass combustion, and from secondary sulfate and nitrate were similar with that of the total PM10. The infiltration factor of PM10contributed from vehicle emissions was higher than that of the total PM10. And the infiltration factor of PM10contributed from soil and cement was lower than that of the total PM10. The infiltration factors of particulate matter contributed from different sources were virous, which indicated that the sources and contribution of ambient particulate matter were one of the factors to affect the infiltration factor of particulate matter.(4) The non-cancer and cancer risk for exposing to mental elements (Cr, Mn, Co,Ni, Cu, As, Cd and Pb) associated with PM10were estimated by Monte Carlo simulations. The results indicated that the elderly participants had been facing the threat that they might have cancer for exposing to As and Cr associated with PM10. Based on the sources of personal exposed particulate matter, the As contributed from ambient sources accounted for64.8%of the total personal exposed As, and the cancer risk caused by As contributed from coal and biomass burning accounted for56.3%of that caused by As contributed from ambient sources. The Cr contributed from indoor sources accounted for58.9%of the total personal exposed Cr, and the cancer risk caused by Cr contributed from ETS and cooking accounted for60.1%of that caused by Cr contributed from indoor sources.(5) Health risk of the elderly participants who exposed to PAH associated with PM10contributed from ambient and indoor sources. The incremental lifetime cancer risk for exposing to PAHs associated with PM10was estimated by Monte Carlo simulation. The results indicated that elderly participants had been facing the threat that they might have cancer caused by PAHs associated with PM10. Based on the results of source apportionment of particulate matter, the sources that may cause the highest incremental lifetime cancer risk were coal and biomass combustion, vehicle emissions, and ETS and cooking. The incremental lifetime cancer risk caused by PAHs contributed from these three sources account for64.1%、13.0%and9.0%of the risk caused by exposing to the total personal exposed PAH, respectively.This thesis investigated the infiltration factors of PM contributed from ambient and infoor sources, based on the sources of personal exposure, residential indoor/outdoor and community particulate matter. It is indicated that the infiltration factors of PM contributed from different sources had seanal differences. The health risks for elderly participants who exposed to particulate matter contributed from ambient and indoor sources were estimated to provide scientific evidences for controlling particulate matter emissions and for reducing the human health risk.