Atmospherically Derived Organic Surface Films along an Urban-Rural Gradient
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- 作者：Sarah E. Gingrich ; Miriam L. Diamond ; Gary A. Stern ; and Brian E. McCarry
- 刊名：Environmental Science & Technology
- 出版年：2001
- 出版时间：October 15, 2001
- 年：2001
- 卷：35
- 期：20
- 页码：4031 - 4037
- 全文大小：133K
- 年卷期：v.35,no.20(October 15, 2001)
- ISSN：1520-5851
文摘
Atmospherically derived organic films have been found onan impervious surface along an urban-rural gradient inthe Toronto, Ontario, Canada area. Film thickness andconcentrations, expressed on an aerial basis, of 
es/entities/sum.gif">n-alkanes,es/entities/sum.gif">PCB, es/entities/sum.gif">PAH, and es/entities/sum.gif">OC (organochlorine) pesticidesdecrease along this gradient, coincident with loweratmospheric emissions (PCB and PAH) and less accumulationin thinner rural films (OC pesticides). For PCBs and someOC pesticides, patterns of chemical abundance also shift,indicating a "fresh" pattern near emission sources(downtown) versus aged patterns at rural locations thatare indicative of atmospheric transport. Plant-derived n-alkaneconcentrations were greater at urban than rural sites,and we hypothesize greater urban plant wax productionand erosion due to air pollution. As expected, along the urban-rural gradient the concentration of particle-phase PAHdecreased more rapidly than that of gas-phase compounds,but unexpectedly the contribution of alkylated PAHincreased from urban to rural locations. Distances overwhich concentrations decline by 63% vary from 50 km forpersistent gas-phase compounds (e.g., P1,2CB) to 10-20km for reactive gas-phase compounds (e.g., naphthalene,fluoranthene) to <5-10 km for particle-phase compounds(e.g., P6-10CB, benzo[b]fluoranthene, benzo[e]pyrene).