Temporal variability, sources, and sinks of C1-C5 alkyl nitrates in coastal New England 1Climate Change Research Center, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH 03824, USA
2Department of Chemistry, New Mexico Institute of Mining and Technology, Socorro, NM, 87801, USA
Received: 29 September 2009 – Published in Atmos. Chem. Phys. Discuss.: 03 November 2009 Abstract. Seven C1-C5 alkyl nitrates were measured both on the mainland and
off the coast of New Hampshire using gas chromatographic techniques. Five
separate data sets are presented to characterize the seasonal and diurnal
trends and the major sources and loss processes of these compounds. Based on
in situ measurements conducted at the University of New Hampshire (UNH)
Atmospheric Observing Station at Thompson Farm (TF) located in southeast NH
during winter (January–February) 2002, summer (June–August) 2002, summer
(July–August) 2004, and on daily canister samples collected at midday from
January 2004–February 2008, the median total alkyl nitrate mixing ratio
(ΣRONO2) was 23–25 pptv in winter and 14–16 pptv in summer.
During summers 2002 and 2004, MeONO2 decreased overnight and reached
minimum hourly average mixing ratios in the early morning. Comparison with
wind speed and trace gas trends suggested that dry deposition contributed to
the early morning MeONO2 minimum which is a previously unaccounted for
removal mechanism. The mean dry deposition rate and velocity of MeONO2
was estimated to be −0.5 nmol m−2 hr−1 and 0.13 cm s−1,
respectively. Results from ambient air and surface seawater measurements
made onboard the NOAA R/V Ronald H. Brown in the Gulf of Maine during the 2002 New England
Air Quality Study and from ambient canister samples collected throughout the
Great Bay estuary in August 2003 are also presented. Comparisons between the
alkyl nitrate trends with anthropogenic and marine tracers suggest that a
marine source of alkyl nitrates is not significant in coastal New England.
Given the apparent prominence of a secondary source, comparisons between
observed and predicted alkyl nitrate/parent hydrocarbon ratios were made
which demonstrated that background mixing ratios have a continuous and
prevalent influence on the alkyl nitrate distribution.
Revised: 06 February 2010 – Accepted: 09 February 2010 – Published: 18 February 2010
Citation: Russo, R. S., Zhou, Y., Haase, K. B., Wingenter, O. W., Frinak, E. K., Mao, H., Talbot, R. W., and Sive, B. C.: Temporal variability, sources, and sinks of C1-C5 alkyl nitrates in coastal New England, Atmos. Chem. Phys., 10, 1865-1883, doi:10.5194/acp-10-1865-2010, 2010.