Episodic removal of NO_y species from the marine boundary layer over the North Atlantic

Abstract

Measurements of ozone, carbon monoxide, NOy, NOx, HNO3, particulate NO3−, PAN, PPN, and alkyl nitrates were made at Chebogue Point, Nova Scotia, during July, August, and September 1993, and measurements of ozone, carbon monoxide, NOx and N0y were made at Sable Island, Nova Scotia, during August and September 1993 as part of the North Atlantic Regional Experiment (NARE). Periods of photochemical pollution were observed during which concentrations of the above species were elevated relative to average conditions. The best indicator of the extent of impact was found to be the sum of the C1‐C4 alkyl nitrates. The removal of PAN and PPN by fog droplets through thermal decomposition and subsequent uptake of the peroxyacetyl and peroxypropionyl radicals (PA and PP) was suggested by loss of PAN and PPN during fog. The effect of this chemistry on NOy species in the marine environment will need to be considered. The loss of inorganic nitrate (HNO3 and particulate NO3−), PAN (and to a minor extent PPN) resulted in deviation of the O3 versus NOy‐NOx correlations from that observed in eastern North America.

Levels and pattern of volatile organic nitrates and halocarbons in the air at Neumayer Station (70°S), Antarctic

“…Atherton used a pure deductive kinetic model (Atherton, 1989). Other models consider differences in photochemical degradation velocities using pairs of molecules or groups of molecules like carbon monoxide and alkyl nitrates (Roberts et al, 1996), PAN and alkyl nitrates (Buhr et al, 1990), hydrocarbons and alkyl nitrates (Roberts et al, 1998), NO y and NO x (Trainer et al, 1991), two isomeric alkyl nitrates (Flocke et al, 1998;Schneider and Ballschmiter, 1999) or consider the presence of benzyl nitrate (Schneider et al, 1998a;Schneider and Ballschmiter, 1999). Here we present two different approaches to characterize the ''age'' of air masses.…”

Measurement of total nonmethane organic carbon (Cy): Development and application at Chebogue Point, Nova Scotia, during the 1993 North Atlantic Regional Experiment campaign

“…The exception to this was the high levels of Cy observed at about 1000 LT on August 21, which were associated with northerly flow from Yarmouth and hence were eliminated from the following analysis. The second period was part of the most intense ozone pollution episode observed at this site during the study period and has been discussed in detail by Roberts et al [1996]. This ozone episode was caused Future investigations should include improved measurement techniques, additional measurements of species such as alcohols, and improved coordination of sampling times.…”

Closing the peroxy acetyl nitrate budget: observations of acyl peroxy nitrates (PAN, PPN, and MPAN) during BEARPEX 2007

“…In addition to gas phase chemical removal, the APN T reservoir can be removed from the atmosphere by reactions in aerosol and fog (Roberts et al, 1996) or by dry deposition (Turnipseed et al, 2006;Farmer and Cohen, 2008;Wolfe et al, 2009). APN T deposition can be an effective net sink for NO x if APNs are lost to surfaces, or it can serve as a source of NO x if deposition of the corresponding AP radical and concurrent release of NO x is important.…”