Research Of Indoor Human Exposure Based On ICECRM Model

Human chemical exposure can be divided into indoor chemical exposure and outdoor chemical exposure.Compared to outdoor chemical exposure,indoor chemical exposure has more influence on human health,because the time people spend in the room is seven times more than the time they spend outside.However,the information of most chemical exposure is very limit.In the meantime,the assessment of human chemical exposure has become more and more complicated and needs to cover more and more comprehensive exposure scene.In this context,the development of environmental mathematical models makes indoor exposure risk evaluation possible.ICECRM(indoor chemical exposure classification/ranking model)is a steady-state model for the screening-level assessment of near-field human exposure to neutral organic chemicals released indoors.ICECRM adopts an existing multimedia indoor chemical fate model and couples it with a human exposure model.To explore the human chemical exposure level of domestic population,the present study obtained the characteristics of human physiology and parameters of activity pattern of different regions from literature.Based on the ICECRM model toolkit,these data were converted into model input parameters to assess human exposure of 40 common indoor chemicals and provide important research data for risk assessment.The results showed that,Propoxur and Nicotine had the highest total intake fraction(TIF)in the 40 chemicals,their TIF values were 1.58E-01 and 1.45E-01,respectively.The main exposure pathway of these two chemicals was dermal permeation.TBPH had the lowest TIF(7.29E-07)in the 40 chemicals,whose TIF value was 6 orders of magnitude lower than Propoxur.Most of the 40 chemicals affected the human health through respiratory exposure.In addition,the chemicals with dermal permeation as main exposure pathway had a high TIF value,which means these chemicals had high exposure risk.And,the chemicals with dietary exposure as main exposure pathway had a long metabolic half-life,which indicates these chemicals had long exposure risk.The TIF of pesticide is 2.18E-01,which was the highest among different kinds of chemicals.For different chemicals,their rankings based on intake fraction or human concentration were significantly different.Polychlorinated biphenyls have a higher priority level in both rankings than other chemicals,and their long-term exposure risks were worthy of attention.The intake fraction of poly-brominated diphenyl ethers was relatively low,but its human concentration was relatively high.This may due to its relatively long metabolic half-life,which leading to a higher human concentration than other chemicals in the simulation results.The comparison of indoor exposure level of four seasons in Beijing showed that,the air exchange rate is negatively correlated with the indoor human exposure,which indicated that the indoor and outdoor air exchange rate may be an important factor in indoor human exposure.