Comparison of Ammonium Deposition Flux at Roadside and at an Agricultural Area for Long-Term Monitoring: Emission of Ammonia from Vehicles

Abstract

To understand the effect of the NH 3 emissions from vehicles, the NH + 4 bulk deposition and concentrations of gaseous NH 3 and particulate NH + 4 were measured at two sites in Saitama prefecture, Japan, one at the roadside of an arterial road (Kounosu), and the other in an agricultural area (Kisai). We observed that the NH + 4 bulk deposition and NH 3 concentration were significantly increased in Kounosu; the effect of NH 3 emissions from vehicles was confirmed. NOx was a primary pollutant mainly emitted by vehicle exhaust in the vicinity of arterial roads, and the relationship between NO x and sum of gaseous NH 3 and particulate NH + 4 (T-NH + 4 ) was examined. The [T-NH + 4 /NO x ] ratios in Kounosu ranged from 0.08 to 0.23 (average 0.15), and in Kisai they ranged from 0.16 to 0.67 (average 0.39). In Kounosu, the effect of vehicle exhaust was great, but seasonal variation was small. The contribution ratio of NH 3 from vehicle emissions increased at low temperatures, while that from the non-vehicle emissions increased at high temperatures.

Ambient and laboratory observations of organic ammonium salts in PM1

“…NH 3 sources are dominated by agricultural activities such as fertilizer use and livestock. 1 The aforementioned acid-base reactions are the dominant loss process for NH 3 . Ambient concentrations of NH 3 depend strongly on the environment and can reach several ppm in the vicinity of large agricultural areas.…”

“…2 In recent years urban NH 3 concentrations have increased due to the use of selective catalytic reduction to remove nitrogen oxides from car emissions and stacks. 3,4 At the same time signicant reductions have been achieved in the emissions of SO 2 in Europe, 5,6 which diminishes the role of sulfate aerosol but increases the availability of NH 3 to form other salts such as NH 4 NO 3 . 7 NH 4 NO 3 is therefore observed to be the dominant inorganic PM 1 species in many parts of Europe.…”

Theoretical investigation of reactions between ammonia and precursors from the ozonolysis of ethene

“…In remote areas the background level concentration is less than 500 ppt [27] whereas the concentration reaches a few ppm [28] in location with intensive farming. In urban areas, the concentration of ammonia has increasing during the last year due to reduction of nitrogen oxide in catalytic converters placed for example on automobiles [29]. The sinks for emitted ammonia include oxidation of hydroxyl radicals, dry and wet deposition.…”

Characterizing the isotopic composition of atmospheric ammonia emission sources using passive samplers and a combined oxidation‐bacterial denitrifier approach

“…Although the primary source of NH 3 in the USA is from agricultural activities, fossil‐fuel combustion can be a major emission source in urban areas . NH 3 is emitted from vehicles equipped with three‐way catalytic converters (TWC) during the reduction of NO to reduce NO x emissions . NH 3 emissions from road traffic have increased with increased implementation of TWCs since the 1980s.…”

“…By 2000, ~95% of vehicles in the USA were equipped with TWCs . NH 3 concentrations along heavily trafficked roads have been reported to be 3 to 5 times higher than background concentrations and the concentrations near roadways are reported to decrease by 90% within 10 m from the road …”