Long‐term trends in nitrogen oxide emissions from motor vehicles at national, state, and air basin scales

McDonald, Brian; Dallmann, Timothy R.; Martin, Elliot; Harley, Robert A.

doi:10.1029/2012jd018304

Cited by 156 publications

(214 citation statements)

References 29 publications

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“…For example, Fujita et al (2012) found that mobile source NO x emissions from the MOVES model overestimated NO x emissions that had been determined from measurements made in a highway tunnel. A fuel-based emission inventory by McDonald et al (2012) yielded relatively constant on-road mobile source NO x emissions from 1990 to 2000 (compared with a 12% reduction in EPA's trend inventory), but comparable (within 7%) mobile source NO x emissions in 1999 and 2008. Xing et al (2013) report national NO x emissions of~28 mT in 1990 and~14 mT in 2010, compared with EPA's trends inventory of 26 mT and 15 mT in 1990 and 2010, respectively, as shown in Table 1; total NO x emission reductions between 1990 and 2010 are 48% according to Xing et al (2013) and 42% according to EPA (2015d).…”

Section: Precursor Emissionsmentioning

confidence: 99%

Precursor reductions and ground-level ozone in the Continental United States

Hidy¹,

Blanchard²

2015

Journal of the Air & Waste Management Association

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Numerous papers analyze ground-level ozone (O 3 ) trends since the 1980s, but few have linked O 3 trends with observed changes in nitrogen oxide (NO x ) and volatile organic compound (VOC) emissions and ambient concentrations. This analysis of emissions and ambient measurements examines this linkage across the United States on multiple spatial scales from continental to urban. O 3 concentrations follow the general decreases in both NO x and VOC emissions and ambient concentrations of precursors (nitrogen dioxide, NO 2 ; nonmethane organic compounds, NMOCs). Annual fourth-highest daily peak 8-hr average ozone and annual average or 98th percentile daily maximum hourly NO 2 concentrations show a statistically significant (p < 0.05) linear fit whose slope is less than 1:1 and intercept is in the 30 to >50 ppbv range. This empirical relationship is consistent with current understanding of O 3 photochemistry. The linear O 3 -NO 2 relationships found from our multispatial scale analysis can be used to extrapolate the rate of change of O 3 with projected NO x emission reductions, which suggests that future declines in annual fourth-highest daily average 8-hr maximum O 3 concentrations are unlikely to reach 65 ppbv or lower everywhere in the next decade. Measurements do not indicate increased annual reduction rates in (high) O 3 concentrations beyond the multidecadal precursor proportionality, since aggressive measures for NO x and VOC reduction are in place and have not produced an accelerated O 3 reduction rate beyond that prior to the mid-2000s. Empirically estimated changes in O 3 with emissions suggest that O 3 is less sensitive to precursor reductions than is found by the CAMx (v. 6.1) photochemical model. Options for increasing the rate of O 3 change are limited by photochemical factors, including the increase in NO x sensitivity with time (NMOC/NO x ratio increase), increase in O 3 production efficiency at lower NO x concentrations (higher O 3 /NO y ratio), and the presence of natural NO x and NMOC precursors and background O 3 .Implications: This analysis demonstrates empirical relations between O 3 and precursors based on long term trends in U.S. locations. The results indicate that ground-level O 3 concentrations have responded predictably to reductions in VOC and NO x since the 1980s. The analysis reveals linear relations between the highest O 3 and NO 2 concentrations. Extrapolation of the historic trends to the future with expected continued precursor reductions suggest that achieving the 2014 proposed reduction in the U.S. National Ambient Air Quality Standard to a level between 65 and 70 ppbv is unlikely within the next decade. Comparison of measurements with national results from a regulatory photochemical model, CAMx, v. 6.1, suggests that model predictions are more sensitive to emissions changes than the observations would support.

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Section: Precursor Emissionsmentioning

confidence: 99%

Precursor reductions and ground-level ozone in the Continental United States

Hidy¹,

Blanchard²

2015

Journal of the Air & Waste Management Association

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“…Likewise, NO x decreases in Bakersfield have been observed (from space) at approximately the same rate . NO x controls on heavy-duty diesel trucks that are in the implementation phase (McDonald et al, 2012) will reduce NO x emissions without concomitant VOC decreases and bring about the −50 % NO x scenario relatively quickly. Figure 7 shows the absolute P O 3 (ppb h −1 ) and percentage changes calculated during CalNex (black) on weekdays (solid line) and weekends (dashed line) for the three scenarios.…”

Section: Ozone Production Rates and The Impacts Of Emissions Controlsmentioning

confidence: 99%

On the temperature dependence of organic reactivity, nitrogen oxides, ozone production, and the impact of emission controls in San Joaquin Valley, California

et al. 2014

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Abstract. The San Joaquin Valley (SJV) experiences some of the worst ozone air quality in the US, frequently exceeding the California 8 h standard of 70.4 ppb. To improve our understanding of trends in the number of ozone violations in the SJV, we analyze observed relationships between organic reactivity, nitrogen oxides (NO x ), and daily maximum temperature in the southern SJV using measurements made as part of California at the Nexus of Air Quality and Climate Change in 2010 (CalNex-SJV). We find the daytime speciated organic reactivity with respect to OH during CalNex-SJV has a temperature-independent portion with molecules typically associated with motor vehicles being the major component.Published by Copernicus Publications on behalf of the European Geosciences Union. S. E. Pusede et al.: Temperature-dependent impacts of emission controlsAt high temperatures, characteristic of days with high ozone, the largest portion of the total organic reactivity increases exponentially with temperature and is dominated by small, oxygenated organics and molecules that are unidentified. We use this simple temperature classification to consider changes in organic emissions over the last and next decade. With the CalNex-SJV observations as constraints, we examine the sensitivity of ozone production (P O 3 ) to future NO x and organic reactivity controls. We find that P O 3 is NO x -limited at all temperatures on weekends and on weekdays when daily maximum temperatures are greater than 29 • C. As a consequence, NO x reductions are the most effective control option for reducing the frequency of future ozone violations in the southern SJV.

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“…We present an analysis to identify driving chemical mechanisms and to quantify the effects of large reductions in nitrogen oxides (NO x ) (e.g., Russell et al, 2012;McDonald et al, 2012) on secondary aerosol chemistry. We take advantage of decreased NO x emissions on weekends compared to weekdays, which occur mostly without changes in other gas-phase emissions (e.g., Dallmann et al, 2012), and couple these weekday-weekend patterns to long-term NO x reductions .…”

mentioning

confidence: 99%

On the effectiveness of nitrogen oxide reductions as a control over ammonium nitrate aerosol

et al. 2016

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Abstract. Nitrogen oxides (NO x ) have fallen steadily across the US over the last 15 years. At the same time, NO x concentrations decrease on weekends relative to weekdays, largely without co-occurring changes in other gas-phase emissions, due to patterns of diesel truck activities. These trends taken together provide two independent constraints on the role of NO x in the nonlinear chemistry of atmospheric oxidation. In this context, we interpret interannual trends in wintertime ammonium nitrate (NH 4 NO 3 ) in the San Joaquin Valley of California, a location with the worst aerosol pollution in the US and where a large portion of aerosol mass is NH 4 NO 3 . Here, we show that NO x reductions have simultaneously decreased nighttime and increased daytime NH 4 NO 3 production over the last decade. We find a substantial decrease in NH 4 NO 3 since 2000 and conclude that this decrease is due to reduced nitrate radical-initiated production at night in residual layers that are decoupled from fresh emissions at the surface. Further reductions in NO x are imminent in California, and nationwide, and we make a quantitative prediction of the response of NH 4 NO 3 . We show that the combination of rapid chemical production and efficient NH 4 NO 3 loss via deposition of gas-phase nitric acid implies that high aerosol days in cities in the San Joaquin Valley air basin are responsive to local changes in NO x within those individual cities. Our calculations indicate that large decreases in NO x in the future will not only lower wintertime NH 4 NO 3 concentrations but also cause a transition in the dominant NH 4 NO 3 source from nighttime to daytime chemistry.

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Long‐term trends in nitrogen oxide emissions from motor vehicles at national, state, and air basin scales

Cited by 156 publications

References 29 publications

Precursor reductions and ground-level ozone in the Continental United States

Precursor reductions and ground-level ozone in the Continental United States

On the temperature dependence of organic reactivity, nitrogen oxides, ozone production, and the impact of emission controls in San Joaquin Valley, California

On the effectiveness of nitrogen oxide reductions as a control over ammonium nitrate aerosol

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