Estimates of background surface ozone concentrations in the United States based on model-derived source apportionment

Lefohn, Allen S.; Emery, Chris; Shadwick, Douglas S.; Wernli, Heini; Jung, Jaegun; Oltmans, S. J.

doi:10.1016/j.atmosenv.2013.11.033

Cited by 68 publications

(71 citation statements)

References 44 publications

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“…There also is stratospheric O 3 intrusion, especially in the spring, that influences O 3 background (e.g., Lefohn et al, 2014). Modeling estimates of background have been discussed in EPA's (2014a) recent RIA.…”

Section: Significance Of Backgroundmentioning

confidence: 99%

“…EPA (2012) has addressed a background level in the United States using modeling estimates supported by work of Emery et al (2012). More recently, Lefohn et al (2014) have estimated background O 3 levels in several U.S. cities. Lefohn et al (2014) note that the U.S. continental background should be defined with two components, a global component and a North American continental component that includes the chemical interactions with anthropogenic and natural precursor emissions over multispatial scales.…”

Section: Significance Of Backgroundmentioning

confidence: 99%

“…More recently, Lefohn et al (2014) have estimated background O 3 levels in several U.S. cities. Lefohn et al (2014) note that the U.S. continental background should be defined with two components, a global component and a North American continental component that includes the chemical interactions with anthropogenic and natural precursor emissions over multispatial scales. Both seasonally and spatially estimated O 3 background levels vary.…”

Section: Significance Of Backgroundmentioning

confidence: 99%

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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: Significance Of Backgroundmentioning

confidence: 99%

Section: Significance Of Backgroundmentioning

confidence: 99%

Section: Significance Of Backgroundmentioning

confidence: 99%

See 1 more Smart Citation

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

Hidy¹,

Blanchard²

2015

Journal of the Air & Waste Management Association

View full text Add to dashboard Cite

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“…These results were confirmed in a long-term perspective (2050) by , who emphasised that air quality legislation was indeed anticipated to bear its fruit in reducing ozone exposure in the future, even if under a business-as-usual scenario such as the RCP8.5, climate change and long-range transport. Similarly, in the US context there has been much debate as to the contribution and quantification of background ozone and its effect on the attainment of standards (Lefohn et al, 2014;Fiore et al, 2014Fiore et al, , 2002Prather et al, 2003). Lefohn et al (2014) explored the concept of an emissions-influenced background in an attempt on a continental scale to partition the controllable ozone (see Fig.…”

Section: Ozone Mitigation and Baseline Ozonementioning

confidence: 99%

Tropospheric ozone and its precursors from the urban to the global scale from air quality to short-lived climate forcer

et al. 2015

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Abstract. Ozone holds a certain fascination in atmospheric science. It is ubiquitous in the atmosphere, central to tropospheric oxidation chemistry, yet harmful to human and ecosystem health as well as being an important greenhouse gas. It is not emitted into the atmosphere but is a byproduct of the very oxidation chemistry it largely initiates. Much effort is focused on the reduction of surface levels of ozone owing to its health and vegetation impacts, but recent efforts to achieve reductions in exposure at a country scale have proved difficult to achieve owing to increases in background ozone at the zonal hemispheric scale. There is also a growing realisation that the role of ozone as a short-lived climate pollutant could be important in integrated air quality climate change mitigation. This review examines current understanding of the processes regulating tropospheric ozone at global to local scales from both measurements and models. It takes the view that knowledge across the scales is important for dealing with air quality and climate change in a synergistic manner. The review shows that there remain a number of clear challenges for ozone such as explaining surface trends, incorporating new chemical understanding, ozone-climate coupling, and a better assessment of impacts. There is a clear and present need to treat ozone across the range of scales, a transboundary issue, but with an emphasis on the hemispheric scales. New observational opportunities are offered both by satellites and small sensors that bridge the scales.

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“…Ozone gas relevance has been previously emphasised by the authors [13]. Significant volume of research activities which are not just limited to detection and monitoring are devoted to ozone gas [20][21][22][23][24][25][26][27][28]. These activities are summarised in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

Fundamental Review to Ozone Gas Sensing Using Optical Fibre Sensors

et al. 2015

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The manuscript is a review of basic essentials to ozone gas sensing with optical methods. Optical methods are employed to monitor optical absorption, emission, reflectance and scattering of gas samples at specific wavelengths of light spectrum. In the light of their importance in numerous disciplines in analytical sciences, necessary integral information that serves both as a basis and reference material for intending researchers and others in the field is inevitable. This review provides insight into necessary essentials to gas sensing with optical fibre sensors. Ozone gas is chosen as a reference gas. Simulation results for ozone gas absorption cross section in the ultraviolet (UV) region of the spectrum using spectralcalc.com simulation have also been included.

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Estimates of background surface ozone concentrations in the United States based on model-derived source apportionment

Cited by 68 publications

References 44 publications

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

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

Tropospheric ozone and its precursors from the urban to the global scale from air quality to short-lived climate forcer

Fundamental Review to Ozone Gas Sensing Using Optical Fibre Sensors

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