Study On Correlation And Exposure Level Of Indoor And Outdoor Particle Pollution In Severe Cold Regions

In recent years,the problem of outdoor particulate pollution in China has become increasingly prominent.Inhalable particles(PM₁₀,PM_2.5)have become the primary pollutants in most cities.More and more epidemiological studies show that there is a positive correlation between the morbidity and mortality of human body and the mass concentration of fine particles.While most of human life is spent indoors,the pollution of outdoor airborne particulates can seriously affect indoor air quality through ventilation,affecting human health.Therefore,it is particularly important to study the correlation between indoor and outdoor particulate pollution.In order to study the correlation and exposure level of indoor and outdoor particulate matter concentration in the non-heating and heating seasons in the severe cold region of Daqing,110 households of four types of buildings?offices,classrooms,rural residences and urban residences?were tested and analyzed by the on-line monitoring instruments.The infiltration coefficient is used to express the correlation between indoor and outdoor particulate concentrations,which found that there are significant differences between the indoor and outdoor infiltration coefficients obtained for different buildings types in the non-heating and heating seasons.Moreover,indoor and outdoor particulate matter correlation has a certain relationship with outdoor air quality,temperature and relative humidity,wind speed and direction,and atmospheric pressure,however there are differences in the degree of correlation between different influencing factors.The bivariate analysis method was applied to analyze the correlation between indoor particulate matter concentration and influencing factors,and the comparative analysis found that there was a clear seasonal difference.Then,the multiple linear regression?MLR?and principal component regression?PCR?are used to establish indoor particle concentration prediction model based on indoor and outdoor influencing factors.Through comparative analysis of the performance indicators of the two models,it is indicated that the MLR model was superior to the PCR model in the non-heating season.In the heating season,MLR model is superior to the PCR model for the office buildings,and there is no significant difference between the two models for classrooms and urban residential buildings.However,the PCR model is better than the MLR model for rural residential buildings.Overall,the MLR model is superior to the PCR model,but it is necessary to consider the variables parameters and the specific environment in the field selection.At the last part of this paper,combining the measured and simulated results,the short-term and long-term exposure level of different groups of people was studied in indoor and outdoor environments of Daqing area based on the time-activity model of personnel,and comprehensive exposure,average comprehensive exposure,comprehensive potential dose and average comprehensive potential dose were used to comprehensively evaluate exposure levels.The results show that the average integrated exposure in the heating season is more than 60%higher than that in the non heating season.The average integrated exposure and average integrated potential dose of the rural population are about 11%higher than that of the urban population.The average comprehensive exposure and average comprehensive potential dose for male are about 20%higher than that of the female.Therefore,the research on the correlation of indoor and outdoor particulate pollution has clearly revealed the influencing factors and established the indoor particle concentration prediction model in this paper,which has important scientific significance for solving the problems of indoor and outdoor particulate matter pollution.Moreover,the research methods for short-term and long-term exposure of indoor and outdoor particulate matter provide important scientific basis for the study of health risks of indoor and outdoor particulate matter.