Martin O’Malley, Governor | Anthony G. Brown, Lt. Governor | Shari T. Wilson, Secretary AQ Cycles Re-examined: Shifting of the Bermuda High and Changes in Regional Ozone Patterns Duc Nguyen, Senior Meteorologist Michael Woodman, Chief Air Quality Measurements, Modeling and Analysis Division Ambient Air Monitoring Program Presented at: 2010 National Air Quality Conferences Raleigh, NC March 18, 2010 Duc Nguyen, Senior Meteorologist Michael Woodman, Chief Air Quality Measurements, Modeling and Analysis Division Ambient Air Monitoring Program Presented at: 2010 National Air Quality Conferences Raleigh, NC March 18, 2010

Outline  Ozone Exceedance Days and 90  F Cycle  Ozone Season NO x Emissions  Air Quality (AQ) Cycles  Pre/Post Adjustments for AQ Improvements  Estimate Magnitude of AQ Improvements  Bermuda High and Regional Ozone Patterns  Outlook for 2010  Summary  Ozone Exceedance Days and 90  F Cycle  Ozone Season NO x Emissions  Air Quality (AQ) Cycles  Pre/Post Adjustments for AQ Improvements  Estimate Magnitude of AQ Improvements  Bermuda High and Regional Ozone Patterns  Outlook for 2010  Summary

Maryland 8-Hour Ozone Exceedances Days vs. ≥ 90 F Days 3 years5 years 3 years 4 years 3 years 5 years? *2009 data are preliminary.

Ozone Exceedance Days and 90  F Cycle ??  Standardized departure of Maryland’s 8-hour ozone exceedance days (OEDs) and 90 deg F days at BWI follow a periodic cycle through Correlation is 0.67  OEDs are consistently below normal since 2002 (indicating air quality improvements) regardless of temperature data.  Nguyen & Wooodman (2008) showed that the air quality improvements were driven by effective control strategies.

Controls in Action … Ozone Season NOx Emissions Figures extracted from EPA’s NOx Budget Trading Program 2008 Progress Report.NOx Budget Trading Program 2008 Progress Report  Compared to 1990 emissions, ozone season NO x emissions cut by 62% in  By 2008, NO x emissions decreased by 75%.

NOx SIP Call Help LEVELING Upwind NO x Emissions! Ozone Season NO x Emissions by State Map created by Maryland Department of the Environment using data extracted from Clean Air Markets - Data and Maps website.Clean Air Markets - Data and Maps

Characteristics of AQ Cycle EXCEEDANCE TENDENCY More Days (Orange and Red) Above Normal (Shades of Red) Warmer Weather Near Average (Gray) Near Normal (White) Near Normal Less Days (Green and Blue) Below Normal (Shades of Blue) Cooler Weather UPPER-LEVEL PRESSURE/HEIGHT CORESSPONDING SFC TEMPERATURE Remark These characteristics can be observed spatially and temporally.

Higher Pressure ~ Above Normal Counts Year 3 Air Quality Cycle ( )  Normal (Air Quality): 10-year ( )  Normal (Meteorology): 30-year ( )  Months: Jun-Aug Year 2 About Normal Pressure ~ Some Above & Some Below Year 1 Lower Pressure ~ Below Normal Counts This cycle has all the classic characteristics described on previous slide! Maps created using data extracted from AIRNowTech and ESRL PSD Plotting and Analysis. Some preliminary AQ data were used in the analysis.AIRNowTechESRL PSD Plotting and Analysis

Slightly Below Normal & Normal Pressure BUT Many Below Normal Counts Higher Pressure BUT Many Below Normal Counts Lower Pressure ~ Below Normal Counts Air Quality Cycle ( ) Relationship starting to break … Relationship broke down … Slightly Lower Pressure ~ Below Normal Counts Normal & Higher Pressure BUT Many Below Normal Counts Analysis in 2007 indicated that air quality improvements have been driven by effective control strategies (e.g. NOx SIP Call)! Maps created using data extracted from AIRNowTech and ESRL PSD Plotting and Analysis. Some preliminary AQ data were used in the analysis.AIRNowTechESRL PSD Plotting and Analysis

Pre/Post NO x SIP Call OEDs (Baltimore, MD MSA) Pre NO x SIP Call OEDs Post NO x SIP Call OEDs *2009 data are preliminary.

Pre/Post NO x SIP Call OEDs (Washington, DC-MD-VA-WV MSA) Pre NO x SIP Call OEDs Post NO x SIP Call OEDs *2009 data are preliminary.

Pre/Post NO x SIP Call OEDs (Philadelphia, PA-NJ MSA) Pre NO x SIP Call OEDs Post NO x SIP Call OEDs *2009 data are preliminary.

Pre/Post NO x SIP Call OEDs (Boston, MA-NH MSA) *2009 data are preliminary. Periphery of I-95 Ozone Plume

Pre/Post NO x SIP Call OEDs (Columbus, OH MSA) *2009 data are preliminary. Upwind of Maryland and OTC States

Slightly Below Normal & Above Normal Pressure ~ Normal and Above Normal Counts Higher Pressure ~ Above Normal Counts Lower Pressure ~ Below Normal Counts Air Quality Cycle ( ) (Adjusted for Recent Data) Relationship is now intact! Relationship is restored after adjustments for recent data … Normal & Above Normal Pressure ~ Normal/Below Normal (North) Above Normal (South) Slightly Lower Pressure but Some Normal & Above Normal Counts Next Step: Compare ozone exceedances pre/post NOx SIP Call to estimate its effectiveness. Maps created using data extracted from AIRNowTech and ESRL PSD Plotting and Analysis. Some preliminary AQ data were used in the analysis.AIRNowTechESRL PSD Plotting and Analysis

Air Quality Improvements Pre/Post NO x SIP Call (1 of 2)  Similar meteorology between 2004 and 2009 allows us to estimate the minimum benefits for the NO x SIP Call.  Substantial number of MSAs observe OEDs improve by one category. (i.e “Normal”  “Below Normal”  “Well Below Normal”

Air Quality Improvements Pre/Post NO x SIP Call (2 of 2)  East of Mississippi experienced reduction of 30% or more in OEDs (highest reductions in rural settings).  7 MSAs increase in OEDs but small averages and mainly located west of Mississippi.  Need another round of EMISSION REDUCTIONS to help OTC states and major cities attain new stringent ozone standard.  East of Mississippi experienced reduction of 30% or more in OEDs (highest reductions in rural settings).  7 MSAs increase in OEDs but small averages and mainly located west of Mississippi.  Need another round of EMISSION REDUCTIONS to help OTC states and major cities attain new stringent ozone standard. Maps were created using preliminary data extracted from AIRNowTech.AIRNowTech

Cycle Since 2008  Data suggest that 2008 and 2009 were the beginning of a new cycle consisting of 2 beginning low years.  This information is crucial for seasonal AQ outlook for 2010 (i.e., likely to be normal or above normal counts).  Data suggest that 2008 and 2009 were the beginning of a new cycle consisting of 2 beginning low years.  This information is crucial for seasonal AQ outlook for 2010 (i.e., likely to be normal or above normal counts). Below Normal Pressure ~ Normal/Below Normal Counts Well Below Normal Pressure ~ Mostly Below Normal Counts Maps created using data extracted from AIRNowTech and ESRL PSD Plotting and Analysis. Some preliminary AQ data were used in the analysis.AIRNowTechESRL PSD Plotting and Analysis

Large-Scale Circulations Source:  Large-scale circulation creates strong subsidence around 30° N.  Subsidence creates semi-permanent Subtropical highs at the surface around the globe.  Over the Atlantic Ocean, it’s referred to as “Azores / Bermuda High.”  Strength of High increases with height.

Bermuda High: Classic Mid-Atlantic Air Pollution Weather

Shifting of Bermuda High During Low vs High Ozone Seasons Bermuda High is Responsible for Wind Flow & Pollution Transport Patterns in Maryland and the Mid-Atlantic.

Outlook for 2010 (1 of 2)  Latest ENCEP coupled forecast system (CFS) predicts weak Warm ENSO (El Niño) conditions to persist through 2010 summer.  Various other models also predict weak warm ENSO or normal conditions through 2010 summer.  If forecasts verify the Mid-Atlantic region will likely be experiencing normal or above normal temperatures and/or dry conditions during the 2010 summer air quality season. Sources: NCDC ENSO Diagnostic Discussion | CFS Seasonal Climate Forecasts IRI ENSO QuicklookNCDC ENSO Diagnostic DiscussionCFS Seasonal Climate Forecasts IRI ENSO Quicklook

Outlook for 2010 (2 of 2)  CDC outlooks calls for warmer than normal temperatures through summer of  AQ Cycle suggests high probability of normal or above normal OEDs for  Much of the Eastern United States (Northeast, Mid-Atlantic, and Ohio River Valley) should experience an increase in OEDs (above normal counts for 8-hour ozone exceedances) in  The benefits of the regional NOx control program and Maryland Healthy Air Act should offset this increase.  CDC outlooks calls for warmer than normal temperatures through summer of  AQ Cycle suggests high probability of normal or above normal OEDs for  Much of the Eastern United States (Northeast, Mid-Atlantic, and Ohio River Valley) should experience an increase in OEDs (above normal counts for 8-hour ozone exceedances) in  The benefits of the regional NOx control program and Maryland Healthy Air Act should offset this increase. Source: CDC Three-Month OutlooksThree-Month Outlooks

Summary (1 of 2)  Maryland OEDs can be broken down into 3-5 year periods, trending with the 90 degree days cycle to minimize the year-to-year fluctuations in meteorology. OEDs by each period showed continuous improvements. Significant improvements are observed after implementation of a large-scale multi-state NO x control program (NO x SIP Call).  As much as 30-90% reductions in OEDs are observed in MSAs across the eastern U.S post NO x SIP Call.  Significant AQ improvements require that AQ Cycle post 2002 be adjusted for trends in regional ozone patterns.  Shifting of the Bermuda high creates fluctuations in seasonal weather patterns and combined with reduced emissions causes changes in regional ozone patterns.  At the surface, the Appalachian lee-side trough is enhanced along the I-95 corridor during high pollution years, indicating short and mid-range transport patterns from south/southwest are pronounced.  The enhanced trough line is associated with Maryland OEDs and potentially the development of the Nocturnal Low Level Jet (NLLJ).  Maryland OEDs can be broken down into 3-5 year periods, trending with the 90 degree days cycle to minimize the year-to-year fluctuations in meteorology. OEDs by each period showed continuous improvements. Significant improvements are observed after implementation of a large-scale multi-state NO x control program (NO x SIP Call).  As much as 30-90% reductions in OEDs are observed in MSAs across the eastern U.S post NO x SIP Call.  Significant AQ improvements require that AQ Cycle post 2002 be adjusted for trends in regional ozone patterns.  Shifting of the Bermuda high creates fluctuations in seasonal weather patterns and combined with reduced emissions causes changes in regional ozone patterns.  At the surface, the Appalachian lee-side trough is enhanced along the I-95 corridor during high pollution years, indicating short and mid-range transport patterns from south/southwest are pronounced.  The enhanced trough line is associated with Maryland OEDs and potentially the development of the Nocturnal Low Level Jet (NLLJ).

Summary (2 of 2)  Shifting of the Bermuda high creates an anomalous high over the upwind states (Plains, Great Lakes and Midwest) during high pollution years.  On average, the anomalous high is 3.5 deg F warmer for a column of air from the surface to 850-mb level and results in high ozone production in upwind states.  The enhanced ozone concentrations during high pollution years in the Mid-Atlantic and Northeast are driven by local pollutant sources and to a greater extend transported pollution.  Maryland and other northeastern states need another round of broad regional control programs on top of local controls to attain a more stringent 8-hour standard!  Shifting of the Bermuda high creates an anomalous high over the upwind states (Plains, Great Lakes and Midwest) during high pollution years.  On average, the anomalous high is 3.5 deg F warmer for a column of air from the surface to 850-mb level and results in high ozone production in upwind states.  The enhanced ozone concentrations during high pollution years in the Mid-Atlantic and Northeast are driven by local pollutant sources and to a greater extend transported pollution.  Maryland and other northeastern states need another round of broad regional control programs on top of local controls to attain a more stringent 8-hour standard!

Maryland Department of the Environment 1800 Washington Boulevard | Baltimore, MD | TTY Users: Martin O’Malley, Governor | Anthony G. Brown, Lt. Governor | Shari T. Wilson, Secretary Contact Duc Nguyen Senior Meteorologist Ambient Air Monitoring Program Air and Radiation Management Administration

References 1.AIRNowTech – National real-time repository of real-time air quality data provided by EPA AIRNow program ( 2.CFS Seasonal Climate Forecasts web site ( 3.Clean Air Markets - Data and Maps web site ( 4.Climate Prediction Center: Three-Month Outlooks web site: ( 5.Global wind animation ( 6.IRI ENSO Quicklook web site ( 7.Interactive plotting and analysis pages by ESRL / PSD / CDC ( 8.NOx Budget Trading Program 2008 Progress Reports by EPA ( 9.Nguyen & Woodman (2008). Air Quality Variability in Maryland due to Climate Cycles and Emissions. Retrieved from AIRNow NAQ web site: AIRNowTech – National real-time repository of real-time air quality data provided by EPA AIRNow program ( 2.CFS Seasonal Climate Forecasts web site ( 3.Clean Air Markets - Data and Maps web site ( 4.Climate Prediction Center: Three-Month Outlooks web site: ( 5.Global wind animation ( 6.IRI ENSO Quicklook web site ( 7.Interactive plotting and analysis pages by ESRL / PSD / CDC ( 8.NOx Budget Trading Program 2008 Progress Reports by EPA ( 9.Nguyen & Woodman (2008). Air Quality Variability in Maryland due to Climate Cycles and Emissions. Retrieved from AIRNow NAQ web site: