Western Ozone Conference Understand the nature, causes and trends of ozone in the western U.S. outside CA Identify additional assessment work needed to better characterize ozone Identify the policy development needed to address the problem

Overview Summarize Conference Information Discuss Conclusions Discuss Recommendations

Conference Overview Regulatory Overview –Federal –Early Action Compacts Regional Trends –Regional Monitoring Modeling –Mobile Controls Case Studies –NM, CO, WA, OR, ID Modeling –WY, AZ, NM Monitoring Special topics –Gas Production –Fire

Not a uniquely important region in terms of impact Several studies in North Pacific region over last 2 decades Why focus on Asian Emissions, North Pacific and US West Coast? Asian emissions increased significantly over period of studies - Look for parallel change in ambient levels

(Data selected to avoid North American influence) Conclusion: Along the U.S. west coast, springtime O 3 has increased by ≈ 0.5 ppbv/yr, i.e. ≈10 ppbv in 20 years or ≈1-1.5 %/yr Increasing background ozone during spring on the west coast of North America, Jaffe et al., Geophys. Res. Letters, 30, 2003 Springtime mean O 3 levels have increased

Summary: In springtime Impact of Asian Emissions on the Photochemistry of the North Pacific Troposphere Asian emissions have increased by ≈ 5% / year over last 20 years O 3 levels in Eastern Pacific have increased by ≈ % / year PAN levels in Eastern Pacific have increased by ≈ 3-4 % / year Pacific photochemistry has become less efficient sink for O 3 Caveat: Based on very few “background” data of short time span Pt. Arena data are only early PAN and VOC measurements collected over 10 day period

How do ozone concentrations in national parks compare with nearby urban areas?

Do diurnal patterns of ozone differ from parks to nearby urban areas?

Expected Ozone Trends – Federal Emissions Reductions Heavy Duty Engine & Diesel Sulfur –Issued in 2001 –Emissions standards for heavy-duty trucks and buses, plus fuel sulfur limits –95% less NOx emissions from category –Effective in model year 2006/07, phase in (09/10) NonRoad Engine & Diesel Sulfur –Proposed in 2003, Expected final in April 2004 –Emissions standards for construction, agricultural, and industrial equipment –90% less NOx emissions from category –Effective in model year 2008, phase in through 2014

Expected Ozone Trends – Future NOx Emissions Changes

Expected Ozone Trends – NonRoad Modeling Analyses Most portions of the western U.S. are projected to have a reduction of 2-10 ppb in peak 8-hr ozone levels by 2020 Greater reductions in majority of CA Disbenefits in LA, SF, DEN (small) & PHX (small)

Eight Hour Ozone Design Values

Projected 2020 Eight Hour Ozone Design Values

Expected Ozone Trends – NR Modeling: Arizona

Expected Ozone Trends – NR Modeling: Colorado

Expected Ozone Trends – NR Modeling: Nevada

Expected Ozone Trends – NR Modeling: New Mexico

Expected Ozone Trends – NR Modeling: Oregon

Expected Ozone Trends – NR Modeling: Utah

Expected Ozone Trends – NR Modeling: Washington

Expected Ozone Trends – NonRoad Modeling Analyses 8-hour ozone levels are generally expected to decrease slightly in the Western U.S. over the next years –Decrease of ~ 5%: Albuquerque, Denver, Phoenix, Salt Lake City, Tucson, & rural areas –Larger decreases: Portland, Seattle –Model results uncertain (your results may vary) –Certain Western U.S. cities are likely to maintain design values near/just below the NAAQS over the next 0-20 years w/o local control – will depend on year-to-year meteorological variability.

CMAQ Western U.S. Ozone Modeling – 1996 Application Model performance evaluation indicated greater negative bias in the western U.S. in the summer than in 36/12 CAMx –Mean normalized bias = -11.7% –Normalized gross error = 23.2 % –East US (annual): bias = -1.2%; error = 18.6% –West US (annual): bias = -26.5%; error = 29.9% –East US (summer): bias = 0.8%; error = 18.7% –West US (summer): bias = -27.0%; error = 30.5%

2007 Emission Reduction Sensitivity Analysis Across-the-Board 10% reduction in anthropogenic emissions in DMA + Weld County (plus on-road and off-road reductions). Key Findings: –Modeled ozone stiff response to local emission reductions (i.e., ozone not very responsive to local emission controls) –VOC control in DMA is more effective than NOx control in DMA 10% VOC control in DMA results in ppb ozone reduction at Rocky Flats North monitor 10% NOx control in DMA results in 0.4 ppb ozone increase at Rocky Flats North monitor

Denver Ozone Source Apportionment Source Apportionment results currently under review by State and Denver RAQC, report not yet available Preliminary results suggest the following: –A majority (~75% to 85%) of the peak 8-hour ozone concentrations at the Rocky Flats monitor come from outside of the Denver Metropolitan Area (DMA) –For sources in the DMA, on-road mobile sources are most important followed by non-road mobile sources Helps explain why modeling results are so stiff in response to local controls

1-Hr Ozone Model Performance, Error – Goal < 35%

Overall Conclusions Western US O3 Modeling Ozone downwind of smaller “urban” areas in western U.S. tends to be underestimated –Seen in recent EACs (CAMx) and Regional Visibility modeling (CMAQ) –Regional buildup of ozone understated Contributing factors: –Missing emissions UCI Oil&Gas, many small unpermitted sources Missing biogenic emissions/understated reactivity Mobile Source fleet type different from national average –Meteorological Modeling More Challenging

2002 Denver Metro and Statewide VOC EI with Biogenic Emissions

MT Emission Inventory Coal Bed Methane Sources

MT Emission Inventory Conventional Oil & Gas Sources

July 19, :15 am SVR = 130 km O 3 = 78 ppb 11:45 am SVR = 54 km O 3 = 86 ppb

July 19, 2002 (3:00-3:45 pm) SVR = 58 km O 3 = 96 ppb (highest O 3 value in 2002)

Conclusions Future not clear/national view may need refinement Many examples, but lack of regional understanding of: –Background, natural, rural/urban, transport/local, regional, subregional-Elevated urban ozone not well synchronized with rural ozone Better analysis of existing situation needed ID policy goals – attainment, maintenance, transport/local, rural/urban, regional/subregional Coordinate/leverage resources High background levels – limited local control options

Recommendations Modeling –Biogenics, meteorology –One atmosphere model Monitoring –Work with existing data –Better collaboration –Better spatial coverage –Collect speciated VOC and NO

Recommendations (cont.) Early Action Compacts –Encourages proactive assessment/action-to identify/address problems before they become nonattainment areas –Continue to make option available Forecasting – continue federal support IAQR – understand effect on ozone Oil and gas – getting better understanding of emissions Fire/ozone –Resolve fire/ozone episode relationship/documentation –Resolve monitor interference question

Questions? ?