VERTICAL CHARACTERISTICS OF THE PM10 AND PM2.5 PROFILE IN AN A REAL URBAN STREET CANYON: CONCENTRATIONS, CHEMICAL COMPOSITION AND ASSOCIATED HEALTH RISKS

摘要

A field work investigating the vertical differentiation of the PM place within a street canyon, in a heavily traffic impacted environment. The measurements were conducted simultaneously on different heights (1st, 5th floor) of a 19m height building, covering both the winter and summer period. The carbonaceous and ionic content as well as up to 20 PAHs were quantified in order to characterize chemically the collected samples. With its average peaks (51.2 ^gm-3) being recorded near the surface, the only significant vertical differentiation was obtained for PM10. In the case of PM2.5, its average values were almost equal at the two heights (33.8 and 34.0 ^gm-3 on the 1st and 5th floor, respectively). For both fractions, the most significant daily PM difference, on the vertical axis, occurred during the summertime (39%). OC was constantly, the main aerosols5 component with increased PM10 constitutional rates during wintertime and for PM2.5 during summer (winter: +14%, +31%, summer: +8%, +4% for the 1st and 5th floor, respectively). The average SPAHs value was 12.8 and 11.6 ng.m-3, on the 1st and 5th floor, respectively while the LMW congeners were the main feature of both heights (49% and 56%). With the increased carcinogenic/mutagenic activity being attributed to the minimum height (1.39 and 1.72 ^gm-3, respectively), the health risk analysis verified the importance of the level of exposure for the local input. Moreover, the significance of BaP alone as a surrogate compound for the PAHs mixture in connection with its carcinogenic/mutagenic potency was clearly underlined (49% - 61%).