Partitioning Characteristics And Health Risks Of PAEs And NPPs In Indoor Multimedia Environment In Northern Cold Area

The long winter heating season in northern China and poor air circulation leads to the presence of phthalate esters（PAEs）and non-phthalate esters（NPPs）in indoor air,dust,and surface films.These chemicals can enter the human body through inhalation,ingestion,and skin absorption,posing a risk to human health.This study simulated the indoor environment of northern residential areas,analyzed the seasonal variations and spatial distribution of PAEs and NPPs in multiple media,identified their sources,and elucidated the distribution patterns of particle/gas,dust/gas,and film/gas partitioning.An indoor multi-media fugacity model was established to analyze the environmental fate of PAEs and NPPs,and to evaluate their health risks,providing the scientific basis for protecting our living environment.This study focused on an undisturbed residence in Harbin,where samples of indoor air（gas and particle phases）,dust（including various particle sizes）,and surface film（on window and furniture surfaces）were collected and analyzed for one year.The results indicated that PAEs and NPPs were present in all media,withΣPAEs exhibiting higher concentrations thanΣNPPs.In the air,dimethyl phthalate（DMP）and diisobutyl adipate（DIBA）were the primary PAEs and NPPs,respectively,whereas di（2-ethyl）hexyl phthalate（DEHP）and Dioctyl terephthalate（DEHT）were prevalent in other media.The mass distribution of dust particle size was mainly composed of fine particles（<125μm）,and the concentration ofΣPAEs was highest in the F4（250-125μm）particle size,while the concentration ofΣNPPs was highest in the F5（63-125μm）particle size.The indoor air PAEs and NPPs showed seasonal and spatial differences,with the highest average concentration in summer.There was little difference in PAEs and NPPs in dust and surface films on window glass among different rooms.There was no significant difference in the PAEs and NPPs in dust and surface films on furniture at different heights.The correlation analysis between indoor environmental factors and the concentration of pollutants in different media shows that the effects of environmental factors（temperature,humidity,total suspended particulates,days,and organic carbon）on the concentrations of pollutants in different media are inconsistent.The influence of environmental factors on pollutants increases as the particle size of dust decreases.By using the mean-median ratio method,it is found that the impacts of static sources or occasional events on different media of phthalate esters（PAEs）and non-phthalate plasticizers（NPPs）are inconsistent.The correlation analysis of PAEs and NPPs shows that pollutants with similar molecular weights have similar sources or environmental behaviors.The principal component analysis method is used to identify the main sources of PAEs and NPPs,including indoor coatings and decorative materials,polyvinyl chloride floor leather and floor wax,toys,and baby foam mattresses.The distribution patterns of PAEs and NPPs between different media show that the partitioning coefficients of particle/gas,dust/gas,and film/gas basically increase with increasing relative molecular weight（the dust/gas partitioning coefficients of different particle sizes are not significantly different）,and each distribution coefficient deviates from the theoretical equilibrium value with increasing Log K_OA.The distribution patterns of target pollutants are closer to the prediction of the steady-state partitioning model.Using the experimental room as a framework,an indoor multi-media（five-phase）fugacity model was constructed.The accuracy of the indoor fugacity model based on steady-state partitioning was shown to be higher when compared to the model based on equilibrium-state partitioning.The model simulated the transport flux among the five media,and the results showed that the transport flux of DEHP had seasonal variations with the highest flux occurring in summer.The main input flux of air was from floor coverings,while the main input flux of other media was from the settling or adsorption of DEHP on air particles.The main output flux of air DEHP was settling to the ground dust,while the main output flux of other media was through degradation and transformation.The simulation results of the fate of DEHP in the five media showed that the main fate of DEHP was in the ground dust.The model simulated the transport and fate of DEHP in indoor environments in Guangzhou and Toronto and found that the results in Toronto were closer to those in Guangzhou and Harbin.Based on Monte Carlo sensitivity analysis of all input parameters,temperature,and source emission rate were found to be the most influential parameters,with a positive correlation coefficient.Monte Carlo predicted that the air DEHP concentration was close to normally distributed,while other media were non-normally distributed.In the indoor microenvironments of northern China,the predicted daily exposure values of DEHP from air,dust,and surface films for five groups of people（infants,toddlers,children,adolescents,and adults）generally decreased in order with increasing age,with ingestion being the main exposure pathway.The results of the health risks of DEHP on the five groups of people simulated by the indoor multi-media fugacity model coupled with the health risk model showed that the daily exposure of the five groups of people decreased with time during the sampling period,with a peak around summer,and the exposure for toddlers being the highest.The health risk index simulated by the model decreased with time.The sensitivity analysis of the input parameters on the health risk index showed that the source emission rate and body weight were the main influencing parameters.The cumulative distribution function and distribution probability of the health risk index showed that the probability of potential health risks for the five groups of people was higher than 80%,and the probability of cancer incidence rates exceeding one in a million people was higher than 99%.