Influence of air mass origin on the wet deposition of nitrogen to Tampa Bay, Florida—An eight-year study

Large-scale spatial variability of major ions in the atmospheric wet deposition along the China–Antarctica transect (31°N–69°S)

“…The ionic concentrations in the wet deposition are dominated by various factors, such as aerosol sources and distribution, transport processes and so on (Celle-Jeanton et al, 2009); in general, the meteorological factors are considered to be the main influencing factors (Strayer et al, 2007). In terms of the ionic origins, both anthropogenic and natural sources should be considered, which include human-related emissions from fuel consumption and agricultural activities, marine aerosols, etc.…”

Precipitation chemistry over urban, rural and high altitude Himalayan stations in eastern India

“…The chemical composition of rainwater strongly depends on the atmospheric chemical composition and several factors are responsible to govern the concentrations of chemical species in precipitation as types and distributions of sources of atmospheric aerosols, gases for both the local and long-range transport, process of scavenging of chemical species by rain (Celle-Jeanton et al, 2009) and micro-meteorological factors (Seto and Hara, 2006;Strayer et al, 2007). There are two main processes through which aerosols and gases get scavenged by rain called below-cloud scavenging or "washout" and in-cloud scavenging or "rainout" (Mouli et al, 2005;Pelicho et al, 2006;André et al, 2007).…”

Application of watershed deposition tool to estimate from CMAQ simulations the atmospheric deposition of nitrogen to Tampa Bay and its watershed

“…Chloride was assumed to be a conservative tracer for atmospheric deposition, such that the expected concentration of N ions in stream water was calculated from the product of the observed stream water chloride ion concentration and the ratio of atmospheric N flux to chloride flux. The ratio of observed to expected N ion concentrations in stream water yielded a minimum N retention of 82% or maximum export of 18% for the watershed, which is lower than the estimate of 26% N export for northeastern U.S. watersheds (Howarth et al, 2006) and higher than the estimate of 6% N export for North Carolina's Neuse River Estuary (Whitall et al, 2003 Figure 1) (Strayer et al, 2007). From the Gandy Bridge data, wet deposition rates were calculated according to eq 1, where C rain is the daily rainfall concentration of either NO 3 À -N or NH 4 þ -N and has units of mg L À1 , D is the rainfall depth and has units of cm d À1 , and F wet is the deposition rate (i.e., flux) and has units of kg N ha À1 d À1 .…”

“…Gases of HNO 3 , HONO, and NH 3 are water soluble and are thus scavenged by rainfall. Precipitation acidity in the range of pH 4-5 (Strayer et al, 2007) favors the disassociation of these compounds into NO 3 À , NO 2 À , and NH 4 þ in rainfall samples. Water-dissolved NO 2 À slowly oxidizes to NO 3 À (Finlayson-Pitts and Pitts, 2000) during the collection, transport, and storage of rainfall samples prior to their analysis at NADP's central laboratory.…”