Trends in on-road vehicle emissions of ammonia

Kean, Andrew J.; Littlejohn, David; Ban-Weiss, George; Harley, Robert A.; Kirchstetter, Thomas W.; Lunden, Melissa M.

doi:10.1016/j.atmosenv.2008.09.085

Cited by 126 publications

(88 citation statements)

References 24 publications

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“…In some regions both sources are important, particularly in regions of mixed land use, such as Denver and Los Angeles (Sun et al, 2017). The eastern portions of the Los Angeles Air Basin are strongly influenced by mobile sources Kean et al, 2009, Leifer et al, 2017. Fraser and Cass (1998) reported that NH 3 emissions from light-duty motor vehicles equipped with three-way catalytic converters are similar in magnitude to agricultural emissions in the Los Angeles Air Basin.…”

Section: Magnitude Of Agricultural and On-road Emissions Of Nhmentioning

confidence: 98%

“…Estimated emissions of NH 3 in the United States increased by 91, 70 and 7% in the on-road, power plant and agricultural sectors, respectively, between 1990 and 2010 (Xing et al, 2013). Emissions of NH 3 from motor vehicles (Kean et al, 2009;Leip et al, 2011) and industrial stacks (Hertel et al, 2011;Li et al, 2017;Vallero, 2014) are largely a byproduct of stringent NO x control technologies. In many regions of the developed world, NO x emissions have steadily declined since around 1990 (Leip et al, 2011) while emissions of NH 3 have remained constant or increased slightly, such as in the United States where NH 3 emissions have increased by 11% (Bytnerowicz et al, 2016;Hertel et al, 2011;Xing et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

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On-road emissions of ammonia: An underappreciated source of atmospheric nitrogen deposition

Fenn

Bytnerowicz

Schilling

et al. 2018

Science of The Total Environment

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H I G H L I G H T S• This study documents the increasing importance of on-road emissions of NH 3.• NO x emissions control mechanisms frequently result in NH 3 production and emissions.• NH 3 is an important driver of N deposition in urban-affected areas and near roadways.• NH 4 -N:NO 3 -N ratios in urban deposition are indicative of elevated NH 3 emissions.• On-road NH 3 emissions exceed agricultural emissions where 40% of the U.S. resides. We provide updated spatial distribution and inventory data for on-road NH 3 emissions for the continental United States (U.S.) On-road NH 3 emissions were determined from on-road CO 2 emissions data and empirical NH 3 :CO 2 vehicle emissions ratios. Emissions of NH 3 from on-road sources in urbanized regions are typically 0.1-1.3 t km −2 yr −1 while NH 3 emissions in agricultural regions generally range from 0.4-5.5 t km G R A P H I C A L A B S T R A C T a b s t r a c t a r t i c l e i n f o, with a few hotspots as high as 5.5-11.2 t km −2 yr −1. Counties with higher vehicle NH 3 emissions than from agriculture include 40% of the U.S. population. The amount of wet inorganic N deposition as NH 4 + from the National Atmospheric Deposition Program (NADP) network ranged from 37 to 83% with a mean of 58.7%. Only 4% of the NADP sites across the U.S. had b45% of the N deposition as NH 4 + based on data from 2014 to 2016, illustrating the near-universal elevated proportions of NH 4 + in deposition across the U.S. Case studies of on-road NH 3 emissions in relation to N deposition include four urban sites in Oregon and Washington where the average NH 4 -N:NO 3 -N ratio in bulk deposition was 2.3. At urban sites in the greater Los Angeles Basin, bulk deposition of NH 4 -N and NO 3 -N were equivalent, while NH 4 -N:NO 3 -N in throughfall under shrubs ranged from 0.6 to 1.7. The NH 4 -N:NO 3 -N ratio at 7-10 sites in the Lake Tahoe Basin averaged 1.4 and 1.6 in bulk deposition and throughfall, and deposition of NH 4 -N was strongly correlated with summertime NH 3 concentrations. On-road

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Section: Magnitude Of Agricultural and On-road Emissions Of Nhmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

On-road emissions of ammonia: An underappreciated source of atmospheric nitrogen deposition

Fenn

Bytnerowicz

Schilling

et al. 2018

Science of The Total Environment

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“…Annual emissions of NO x and NH 3 in the contiguous US in 2010 are shown in Table 2. Mobile emissions of NH 3 are not shown explicitly here, as they are < 4 % of the US total in the NEI2008, although this may be an underestimate in urban areas (Kean et al, 2009). Anthropogenic sources of NO x includes surface sources, electric generating units (EGUs), and non-EGU industrial point sources.…”

Section: Geos-chem Model Descriptionmentioning

confidence: 99%

Sources of nitrogen deposition in Federal Class I areas in the US

et al. 2016

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Abstract. It is desired to control excessive reactive nitrogen (Nr) deposition due to its detrimental impact on ecosystems. Using a three-dimensional atmospheric chemical transport model, GEOS-Chem, Nr deposition in the contiguous US and eight selected Class I areas (Voyageurs (VY), Smoky Mountain (SM), Shenandoah (SD), Big Bend (BB), Rocky Mountain (RM), Grand Teton (GT), Joshua Tree (JT), and Sequoia (SQ)) is investigated. First, modeled Nr deposition is compared with National Trends Network (NTN) and Clean Air Status and Trends Network (CASTNET) deposition values. The seasonality of measured species is generally well represented by the model (R 2 > 0.6), except in JT. While modeled Nr is generally within the range of seasonal observations, large overestimates are present in sites such as SM and SD in the spring and summer (up to 0.6 kg N ha month −1 ), likely owing to model high-biases in surface HNO 3 . The contribution of non-measured species (mostly dry deposition of NH 3 ) to total modeled Nr deposition ranges from 1 to 55 %. The spatial distribution of the origin of Nr deposited in each Class I area and the contributions of individual emission sectors are estimated using the GEOS-Chem adjoint model. We find the largest role of long-range transport for VY, where 50 % (90 %) of annual Nr deposition originates within 670 (1670) km of the park. In contrast, the Nr emission footprint is most localized for SQ, where 50 % (90 %) of the deposition originates from within 130 (370) km. Emissions from California contribute to the Nr deposition in remote areas in the western US (RM, GT). Mobile NO x and livestock NH 3 are found to be the major sources of Nr deposition in all sites except BB, where contributions of NO x from lightning and soils to natural levels of Nr deposition are significant (∼ 40 %). The efficiency in terms of Nr deposition per kg emissions of NH 3 -N, NO x -N, and SO 2 -S are also estimated. Unique seasonal features are found in JT (opposing efficiency distributions for winter and summer), RM (large fluctuations in the range of effective regions), and SD (upwind NH 3 emissions hindering Nr deposition). We also evaluate the contributions of emissions to the total area of Class I regions in critical load exceedance, and to the total magnitude of exceedance. We find that while it is effective to control emissions in the western US to reduce the area of regions in CL exceedance, it can be more effective to control emissions in the eastern US to reduce the magnitude of Nr deposition above the CL. Finally, uncertainty in the nitrogen deposition caused by uncertainty in the NH 3 emission inventory is explored by comparing results based on two different NH 3 inventories; noticeable differences in the emission inventories and thus sensitivities of up to a factor of four found in individual locations.

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“…And the non-agricultural sources include -wild animals (Anderson et al, 2003;Riddick et al, 2012;Simpson et al, 1999;Sutton et al, 2000a;Theobald et al, 2006); -catalyst processes, mainly related to road traffic (Kean et al, 2009;van Vuuren et al, 2011); , and the right side of the figure illustrates the pathway of nitrogen oxides (NO y ) compounds in the atmosphere (NO x = NO + NO 2 and reaction products). The sketch is a modified version of the figure in Hertel et al (2006).…”

Section: Ammonia Emissionsmentioning

confidence: 99%