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Title: Summertime tropospheric nonmethane hydrocarbon and halocarbon concentrations over central and eastern Canada during ABLE-3B. [ABLE (Arctic Boundary Layer Experiment)]

Miscellaneous ·
OSTI ID:6967033

An attempt to understand global tropospheric change was initiated at UCI with the development of a trace gas apparatus to analyze simultaneously nonmethane hydrocarbon (NMHC) and chlorocarbon trace gas species. The experimental design of the equipment used to collect, transfer, and analyze ambient air samples is described. Approximately 1400 whole air samples were collected on the NASA Electra aircraft and at ground locations and were assayed for selected C[sub 2]-C[sub 10] hydrocarbons and seven halocarbons during the Arctic Boundary Layer Experiment (ABLE-3B) conducted in the eastern Canadian Wetlands. Urban plumes, enhanced in many NMHCs, were identified by their high correlation with elevated levels of perchloroethene (C[sub 2]Cl[sub 4]). Meteorological isentropic back-trajectories were used in conjunction with NMHC and halocarbon chemical tracers to confirm the identity of a clean air mass transported to the Canadian Wetlands was attributed to tropical marine air. In more than half of the 46 vertical profiles flown, enhanced NMHC concentrations attributable to plumes from Canadian forest fires were observed. Emission factors relative to ethane were determined for 22 hydrocarbons released from circumpolar biomass burning. Using these data, emissions from biomass burning were calculated to be significant on a global scale. Because of its very short atmospheric lifetime and its below detection background mixing ratio, 1,3-butadiene is an excellent indicator of recent combustion. No statistically significant emissions of N[sub 2]O, isoprene (C[sub 5]H[sub 8]), CCl[sub 2]F[sub 2] (CFC-12) or any other halocarbon were observed in the biomass burning plumes encountered during ABLE-3B. The presence of isoprene at altitudes as high as 3,000 meters implies mixing within the Planetary Boundary Layer (PBL) is rapid.

Research Organization:
California Univ., Irvine, CA (United States)
OSTI ID:
6967033
Resource Relation:
Other Information: Thesis (Ph.D.)
Country of Publication:
United States
Language:
English