Opening Remarks -- Ozone and Particles: Policy and Science Recent Developments & Controversial Issues GERMAN-US WORKSHOP October 9, 2002 G. Foley *US EPA

Opening Remarks -- Ozone and Particles: Policy and Science

Recent Developments & Controversial Issues

GERMAN-US WORKSHOP

October 9, 2002

G. Foley

*US EPA National Exposure Research Laboratory Research Triangle Park, NC

Ozone and Particles: Policy and Science – October 2002

US EPA - National Exposure Research LaboratoryRecent Developments and Controversial Issues

EOHSI - Exposure Measurement & Assessment Division

Modeling Activities Addressing National Issues

GPRA &

ACCOUNTABILITY

ADVANCESIN EXPOSUREMODELING

NEW O3AND PM

STANDARDS




A Revision to the NAAQS for Ozone

The revision changes the one hour standard of 120 ppb to a "concentration-based" form.

Attainment of the standard for an area will be achieved when the 3-year average of the 4th-highest daily maximum 8-hour ozone concentrations is less than or equal to 80 ppb.

The old 1-hour remains in place until that area also has achieved 3 consecutive years of ambient ozone levels meeting the 1-hour standard.




A Revision to the NAAQS for Particulate Matter

The revision adds concentration-based standards for annual and 24-hour exposures to PM-2.5.

For the annual PM-2.5 standard, the 3-year average of the annual arithmetic mean of the 24-hour concentrations from single or multiple population oriented monitored must not exceed 15.0 µg/m3.

For 24-hour PM-2.5, the 98th percentile of the distribution of the 24-hour concentrations for a period of 1 year, averaged over 3 years, must not exceed 65 µg/m3 at each monitor within an area.




Advances in Modeling Tools

During the last decade, air quality modeling has advanced • from single pollutant models to multi-pollutant “one

atmosphere models”• from single scale models to nested multi-scale models that

go from coarse grids of around 100 km down to fine grids of 4 km or less

• with linkages to models, databases, and numerical and analytic tools for probabilistically assessing exposures (and doses) to individuals, populations, and susceptible subpopulations.




The Advanced Models

Two models that embody some of these advances can now be used in “what if” analyses of potential control strategies to meet the new NAAQS —

• EPA's CMAQ (Community Multiscale Air Quality Model), a component of Models-3, and

• EOHSI's MENTOR (Modeling Environment for Total Risk) Framework.




Government Performance and Results Act (GPRA)

• In 1993, President Clinton signed GPRA.• Federal Agencies were challenged to be "accountable" for

achieving program results. • For a program, such as the National Ambient Air Quality

Standards (NAAQS), the EPA was required to• set program goals, e.g. the Clean Air Strategic Goal • measure program performance against these goals and • report publicly on their progress.




The National Goal

"The air in every American community will be safe and healthy to breathe. In particular, children, the elderly, and people with respiratory ailments will be protected from health risks of breathing polluted air."

the Clean Air Strategic Goal from the 1999 GPRA Annual Plan Request to Congress




Modeling Ozone Concentrations and Exposures

The air …. will be safe and healthy to

breathe ….

New Models: Models3/CMAQ

Mentor

New Standards that recognize the expo-

sures that people are experiencing




Population Density (Census Tracts) and CMAQ/MENTOR “Intermediate” Grid for the Modeling Domain of the July 1999

Application




Example: Daily Maxima of 8-hr Average Ozone Concentrations (7/16/1999) for the Inner OTAG Domain (Calculated Using

Models-3/CMAQ)




Relative Effectiveness of VOC vs NOx Intensive Controls in Reducing Daily Maxima of 8-hr Average Ozone Concentrations: NOx Controls

More Effective

Calculations (7/16/1999) for the inner OTAG domain using Models-3/CMAQ and MENTOR





More Effective

base case – NOx_intensivedaily maxima of 8-hr average ozone

concentrations (ppb)

(CMAQ calculations for 7/16/1999)

base case – VOC_intensivedaily maxima of 8-hr average ozone

concentrations (ppb)

(CMAQ calculations for 7/16/1999)




Example: Daily Maxima of 1-hr Average Ozone Concentrations (7/16/1999) for the Inner OTAG Domain (Calculated Using

Models-3/CMAQ)





More Effective





The Application of the New Modeling Tools

• CMAQ simulation results are combined (through MENTOR) with demographic data to estimate the numbers of people potentially exposed to 8-hour ozone averages above 80 ppb across the selected Eastern US domain on July 16, 1999

• The effectiveness of scenarios of across the board intensive VOC reductions (75%VOC/25%NOx) versus intensive NOx reductions (25%VOC/75%NOx) is calculated and compared




Relative Effectiveness of VOC vs NOx Intensive Controls in Reducing Potential Outdoor Ozone Exposures: NOx Controls More Effective for

Both 1 and 8 hr


….. Base Case: 1 hr….. VOC Intensive: 1 hr….. NOx Intensive: 1 hr___ Base Case: 8 hr___ VOC Intensive: 8hr___ NOx Intensive: 8hr




Implications for Policy• Preliminary analyses show that

• Air quality models (CMAQ) can be combined with population exposure models (Mentor) to calculate new metrics, e.g. the population or subpopulation exposed above the NAAQS level

• Exposure-based metrics provide a useful, “information-rich” tool in assessing relative effectiveness of alternative control strategies

- Using such metrics introduces accountability, i.e. reduction of the effects of air pollution on morbidity and mortality, in the process of meeting the air quality standards

• These tools need to be applied at finer spatial scales to examine- Localized control strategies- Voluntary control measures- Changes in human activities resulting from Air Quality

Forecasting




Implications for Model Development• Future policy analyses will require

• Air quality models to be used in Air Quality Forecasting in addition to “what if” analyses of control strategies

• The combined AQ-population exposure models to predict the population or subpopulation exposed to the levels of all of the air pollutants

• AQ models to be run continuously, assimilating monitoring data, to improve performance and realize other benefits

• Next generation models that move to full coupling of meteorology, chemistry, emissions and human activity to further improve performance

Documents

Opening Remarks -- Ozone and Particles: Policy and Science Recent Developments & Controversial Issues GERMAN-US WORKSHOP October 9, 2002 G. Foley *US EPA