PAHs sources contribution to the air quality of an office environment: experimental results and receptor model (PMF) application

摘要

The objectives of this study were to measure the concentrations of PAHs (polycyclic aromatic hydrocarbons) in three particle fractions [particulate matter (PM) <1 μm in diameter (PM1), PM <2.5 μm in diameter (PM2.5) and the respirable fraction (<4 μm in diameter)] in the air of offices in which smoking was allowed and forbidden, respectively, and to identify the potential sources by applying the Positive Matrix Factorization (PMF) model. We sampled the indoor air of both environments during 24-h periods for PM1 and PM2.5 and conducted personal exposure measurements for the respirable PM fraction during working hours. The measurements indicated a clear difference in the levels of carcinogenic PAHs (PAHcancer) in the two office environments. In the smokers' office, PAHcancer levels fell by >70% during the weekend relative to working days, implying the importance of smoking and dust resuspension sources. The PMF model identified four contributory factors-sources: smoking, dust resuspension and two different vehicle-related sources. For 15 PAHs, the same factor made the largest contribution to both the PM1 and PM2.5 fractions, implying a common origin and further supporting the validity of the proposed approach. For the majority of the carcinogenic PAHs, smoking and dust resuspension made the strongest contribution (>90%) tornboth the PM1 and PM2.5 fractions. Although our PMF analysis confirmed the well-known contribution of smoking and traffic-related sources to levels of PAHs, the identification of dust resuspension as a separate source of PAHs is of great interest and requires further study.