Index Geophysics

Multi-year (2004–2008) record of nonmethane hydrocarbons and halocarbons in New England: seasonal variations and regional sources

Multi-year time series records of C₂-C₆ alkanes, C₂-C₄ alkenes, ethyne, isoprene, C₆-C₈ aromatics, trichloroethene (C₂HCl₃), and tetrachloroethene (C₂Cl₄) from canister samples collected during January 2004–February 2008 at the University of New Hampshire (UNH) AIRMAP Observatory at Thompson Farm (TF) in Durham, NH are presented. The objectives of this work are to identify the sources of nonmethane hydrocarbons (NMHCs) and halocarbons observed at TF, characterize the seasonal and interannual variability in ambient mixing ratios and sources, and estimate regional emission rates of NMHCs. Analysis of correlations and comparisons with emission ratios indicated that a ubiquitous and persistent mix of emissions from several anthropogenic sources is observed throughout the entire year. The highest C₂-C₈ anthropogenic NMHC mixing ratios were observed in mid to late winter. Following the springtime minimums, the C₃-C₆ alkanes, C₇-C₈ aromatics, and C₂HCl₃ increased in early to mid summer, presumably reflecting enhanced evaporative emissions. Mixing ratios of C₂Cl₄ and C₂HCl₃ decreased by 0.7±0.2 and 0.3±0.05 pptv/year, respectively, which is indicative of reduced usage and emissions of these halogenated solvents. Emission rates of C₃-C₈ NMHCs were estimated to be 10⁹ to 10¹⁰ molecules cm⁻² s⁻¹ in winter 2006. The emission rates extrapolated to the state of New Hampshire and New England were ~2–60 Mg/day and ~12–430 Mg/day, respectively. Emission rates of benzene, toluene, ethylbenzene, xylenes, and ethyne in the 2002 and 2005 EPA National Emissions Inventories were within ±50% of the TF emission rates.

Russo, R. S.

Zhou, Y.

White, M. L.

Mao, H.

Talbot, R.

Sive, B. C.

2018-01-15

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application/pdf

10.5194/acp-10-4909-2010

https://acp.copernicus.org/articles/10/4909/2010/

eISSN: 1680-7324

eng