Establishing Policy Relevant Background (PRB) Ozone Concentrations in the United States

McDonald-Buller, Elena C; Allen, David T.; Brown, Nancy J.; Jacob, Daniel; Jaffe, Daniel A.; Kolb, C. E.; Lefohn, Allen S.; Oltmans, S. J.; Parrish, D. D.; Yarwood, Greg; Zhang, Lin

doi:10.1021/es2022818

Cited by 75 publications

(59 citation statements)

References 67 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Global modeling studies have reported high-O 3 bias simulated in air arriving along the Texas coast (Fiore et al, 2002(Fiore et al, , 2014McDonald-Buller et al, 2011;Zhang et al, 2011). The high-O 3 bias over 10 ppb has been reported by a regional modeling study (Sarwar et al, 2015;Smith et al, 2015).…”

Section: Regional Mpe Analysis At Remote Sites Along the Gulf Coastmentioning

confidence: 75%

Modeling intercontinental transport of ozone in North America with CAMx for the Air Quality Model Evaluation International Initiative (AQMEII) Phase 3

et al. 2017

Self Cite

View full text Add to dashboard Cite

Abstract. Intercontinental ozone (O 3 ) transport extends the geographic range of O 3 air pollution impacts and makes local air pollution management more difficult. Phase 3 of the Air Quality Modeling Evaluation International Initiative (AQMEII-3) is examining the contribution of intercontinental transport to regional air quality by applying regionalscale atmospheric models jointly with global models. We investigate methods for tracing O 3 from global models within regional models. The CAMx photochemical grid model was used to track contributions from boundary condition (BC) O 3 over a North American modeling domain for calendar year 2010 using a built-in tracer module called RTCMC. RTCMC can track BC contributions using chemically reactive tracers and also using inert tracers in which deposition is the only sink for O 3 . Lack of O 3 destruction chemistry in the inert tracer approach leads to overestimation biases that can exceed 10 ppb. The flexibility of RTCMC also allows tracking O 3 contributions made by groups of vertical BC layers. The largest BC contributions to seasonal average daily maximum 8 h averages (MDA8) of O 3 over the US are found to be from the mid-troposphere (over 40 ppb) with small contributions (a few ppb) from the upper troposphere-lower stratosphere. Contributions from the lower troposphere are shown to not penetrate very far inland. Higher contributions in the western than the eastern US, reaching an average of 57 ppb in Denver for the 30 days with highest MDA8 O 3 in 2010, present a significant challenge to air quality management approaches based solely on local or US-wide emission reductions. The substantial BC contribution to MDA8 O 3 in the Intermountain West means regional models are particularly sensitive to any biases and errors in the BCs. A sensitivity simulation with reduced BC O 3 in response to 20 % lower emissions in Asia found a near-linear relationship between the BC O 3 changes and surface O 3 changes in the western US in all seasons and across the US in fall and winter. However, the surface O 3 decreases are small: below 1 ppb in spring and below 0.5 ppb in other seasons.

show abstract

Section: Regional Mpe Analysis At Remote Sites Along the Gulf Coastmentioning

confidence: 75%

Modeling intercontinental transport of ozone in North America with CAMx for the Air Quality Model Evaluation International Initiative (AQMEII) Phase 3

et al. 2017

Self Cite

View full text Add to dashboard Cite

show abstract

“…Earlier reviews synthesize observations relevant for evaluating base model simulations at remote sites (McDonald-Buller et al, 2011;Reid et al, 2008;Vingarzan, 2004). Even with the same approach, model estimates will differ due to different representations of natural emissions and the choice of different years since meteorological variability alters the balance between transported vs. regionally produced O 3 .…”

Section: Review Of Prior Model Estimates For Nab and Its Componentsmentioning

confidence: 99%

Estimating North American background ozone in U.S. surface air with two independent global models: Variability, uncertainties, and recommendations

Fiore

Oberman

Lin

et al. 2014

Atmospheric Environment

108

131

View full text Add to dashboard Cite

Accurate estimates for North American background (NAB) ozone (O 3 ) in surface air over the United States are needed for setting and implementing an attainable national O 3 standard. These estimates rely on simulations with atmospheric chemistry-transport models that set North American anthropogenic emissions to zero, and to date have relied heavily on one global model. We examine, for the first time, NAB estimates for spring and summer 2006 with two independent global models (GEOS-Chem and GFDL AM3). where it correlates with observed O 3 . At these sites, a 27-year GFDL AM3 simulation simulates observed O 3 events above 60 ppb and indicates a role for year-to-year variations in NAB O 3 in driving their frequency (contributing 50-60 ppb or more during some events). During summer over the eastern United States (EUS), when photochemical production from regional anthropogenic emissions peaks, NAB is largely uncorrelated with observed values and it is lower than at high-altitude sites (average values of ~20-30 ppb). We identify four processes that contribute substantially to model differences in specific regions and seasons: lightning NO x , biogenic isoprene emissions and chemistry, wildfires, and stratosphere-to-troposphere transport. Differences in model representation of these processes contribute more to uncertainty in NAB estimates than the choice of horizontal resolution within a single model. We propose that future efforts seek to constrain these processes with targeted analysis of multi-model simulations evaluated with observations of O 3 and related species from multiple platforms, and thereby reduce the error on NAB estimates needed for air quality planning.

show abstract

“…It is an important quantity for policy as it represents a floor below which air quality cannot be improved by eliminating emissions in the US, Canada, and Mexico. The North American background is not an observable quantity and must therefore be estimated from models (McDonald-Buller et al, 2011). A number of studies have been conducted for this purpose, based on the GEOS-Chem global chemical transport model (CTM) (Fiore et al, 2003;Wang et al, 2009; and the CAMx regional model with GEOS-Chem boundary conditions (Emery et al, 2012).…”

Section: Zhang Et Al: Sources Contributing To Background Surface mentioning

confidence: 99%

Sources contributing to background surface ozone in the US Intermountain West

et al. 2014

View full text Add to dashboard Cite

Abstract. We quantify the sources contributing to background surface ozone concentrations in the US Intermountain West by using the GEOS-Chem chemical transport model with 1/2 • × 2/3 • horizontal resolution to interpret the Clean Air Status and Trends Network (CASTNet) ozone monitoring data for 2006-2008. We isolate contributions from lightning, wildfires, the stratosphere, and California pollution. Lightning emissions are constrained by observations and wildfire emissions are estimated from daily fire reports. We find that lightning increases mean surface ozone in summer by 10 ppbv in the Intermountain West, with moderate variability. Wildfire plumes generate high-ozone events in excess of 80 ppbv in GEOS-Chem, but CASTNet ozone observations in the Intermountain West show no enhancements during these events nor do they show evidence of regional fire influence. Models may overestimate ozone production in fresh fire plumes because of inadequate chemistry and gridscale resolution. The highest ozone concentrations observed in the Intermountain West (> 75 ppbv) in spring are associated with stratospheric intrusions. The model captures the timing of these intrusions but not their magnitude, reflecting numerical diffusion intrinsic to Eulerian models. This can be corrected statistically through a relationship between model bias and the model-diagnosed magnitude of stratospheric influence; with this correction, models may still be useful to forecast and interpret high-ozone events from stratospheric intrusions. We show that discrepancy between models in diagnosing stratospheric influence is due in part to differences in definition, i.e., whether stratospheric ozone is diagnosed as produced in the stratosphere (GEOS-Chem definition) or as transported from above the tropopause. The latter definition can double the diagnosed stratospheric influence in surface air by labeling as "stratospheric" any ozone produced in the troposphere and temporarily transported to the stratosphere. California pollution influence in the Intermountain West frequently exceeds 10 ppbv but is generally not correlated with the highest ozone events.

show abstract

Establishing Policy Relevant Background (PRB) Ozone Concentrations in the United States

Cited by 75 publications

References 67 publications

Modeling intercontinental transport of ozone in North America with CAMx for the Air Quality Model Evaluation International Initiative (AQMEII) Phase 3

Modeling intercontinental transport of ozone in North America with CAMx for the Air Quality Model Evaluation International Initiative (AQMEII) Phase 3

Estimating North American background ozone in U.S. surface air with two independent global models: Variability, uncertainties, and recommendations

Sources contributing to background surface ozone in the US Intermountain West

Contact Info

Product

Resources

About