Ozone NAAQS Implementation: Addressing Background Ozone. Mary Uhl, WESTAR AAPCA spring business meeting March 2019

Transcription

1 Ozne NAAQS Implementatin: Addressing Backgrund Ozne Mary Uhl, WESTAR AAPCA spring business meeting March 2019

2 Five Ozne Planning Needs under the Clean Air Act 1. Ozne NAAQS planning requires phtchemical mdeling fr SIP attainment demnstratins fr nnattainment areas. 2. Ozne transprt SIPs phtchemical surce apprtinment mdeling can be used t quantify U.S. zne transprt between states and ther jurisdictins. 3. Identificatin f Ozne exceptinal events caused by stratspheric intrusin and wildfires requires bservatins and data analysis, supplemented with glbal/reginal scale phtchemical mdels and regressin mdels. 4. Identificatin f internatinal transprt f Ozne fr 179B demnstratins - requires nested glbal and reginal scale phtchemical mdeling t evaluate internatinal transprt f Ozne. 5. Identificatin f 182 Rural Transprt Areas cmbinatin f data analysis and phtchemical mdeling. In the West under CAA, whm t d which? Alne r tgether? - States/Lcals - Reginal - Federal

3 What is U.S. Backgrund Ozne? Any zne frmed frm surces r prcesses ther than U.S. manmade emissins f NOx, VOCs, CH4 and CO. Surces may include: Internatinal transprt f zne precursrs; Stratspheric intrusin f zne; Lightning; Bigenic emissins; Wildfire Alng the west cast, seasnal mean cncentratin is ppb (Jaffe et al., 2004)

4 O 3 Design Values at pairs f mnitring sites Site lcatin Meters Abve Sea Level O 3 Design Value Bend, OR Mt. Bachelr, OR Carbn, WY Centennial, WY Camp Ddge, NH Mt. Washingtn NH Fr nearby lcatins, higher elevatin sites shw much higher O 3 design values, demnstrating hw backgrund zne is mre imprtant at elevatin.

5 Why des backgrund O 3 matter fr NAAQS planning? Cntrllable surces Cnsider U.S. emissins trends (further) by States if nnattainment by EPA if allwed by CAA / litigatin recrd / plicy, i.e., CSAPR Backgrund / uncntrllable surces rlling 3-year NAAQS cmpliance statistic States have t react t variability and magnitude

6 Surces f surface O 3 Dmestic/cntrllable O 3 surces in yellw. Freign/nn-cntrllable O 3 surces in blue.

7 Challenges t quantifying US Backgrund Ozne fr SIPs Cmplex, cntributing surces like wildfire, internatinal transprt and stratspheric intrusin that are difficult fr estimating emissins, mdeling and mnitring Relatively small fractins f lcal anthrpgenic emissins that are cntrllable Need fr a chemical transprt mdel initialized using bundary cnditins derived frm glbal mdels benefits and limitatins f varius mdels fr different uses

8 O3 trends at high elevatin sites in Western U.S. Flat O3 trend in Denver Need t understand rles f: Internatinal and interstate transprt Wildfires Stratspheric O3 Ppulatin grwth Denver & Crestline 4th High 8-hr O3, Denver 4th 8 Crestline 4th Linear (Denver 4th 8) Linear (Crestline 4th) Oil and gas develpment Seasnal variatin

9 600, , ,000 Western Intercnnect Fssil Fuel Pwer Plant Emissins NOx (tpy) mmbtu/10,000 Future 450, , , , , ,000 * 150,000 ** 100, Ozne Standard 1996thrugh 2014 data frm EPA data fr fssil fuel-fired electrical generating units in the 11-state Western Intercnnect * Additinal NOx reductins estimate - BART cntrls frm Reginal Haze baseline planning ** Further NOx reductins estimate frm applying maximum pst-cmbustin cntrls t all remaining units 9

10 Mre mnitring data t imprve characterizatin f backgrund O 3 and t evaluate the accuracy f mdel-based estimates f USB: Mre measurements t imprve characterizatin f vertical O 3 prfiles Netwrk f O 3 LIDAR vertical prfiles (NASA TOLNET pilt study) Mre grund based O 3 and precursr measurements in rural areas Large-scale field experiments crdinated with NASA TEMPO prject Perfrm cmprehensive mdel evaluatin studies using new mnitring data t assess cntributins t backgrund O 3. D glbal mdels accurately estimate BC inflw? D reginal mdels accurately simulate natural surces f O 3 frm wildfires and bigenic precursrs? D reginal mdels accurately simulate vertical mixing f O 3? Strategies fr Imprving US Backgrund Ozne Estimates Need imprved prjectins f future emissins fr uncntrllable surces as well as trends in glbal O3. Increase state/federal & planner/researcher cllabratins t imprve mdeling and data analysis fr O3 transprt, wildfires, and stratspheric intrusin. 10

11 Mary Uhl