Framework for U.S. Air Quality Management and Decision-making Judith C. Chow John G. Watson Desert Research Institute Nevada System of Higher Education Reno, NV, USA Presented at: The Workshop on Air Quality Management, Measurement, Modeling, and Health Effects University of Zagreb, Zagreb, Croatia 24 May, 2007

Objectives Review Air Quality Management Framework Introduce NAAQS establishment process Discuss new PM NAAQS Specify timeline for implementation of standards

Framework for Air Quality Management Bachmann, JAWMA, 2007

U.S. Federal Air Pollution Control Legislation ( ) The Clean Air Act (CAA) of 1963 –Develop and improve state/local air control programs (US$65M) CAA Amendments of 1967 –Maintain state/local air programs (US$55M) CAA Amendments of 1970 –Established structure for air quality management (U.S. EPA set NAAQS) –EPA to regulate stationary sources Technology-based standards for new sources Risk-based standards for hazardous air pollutants

Comparison of U.S. Growth and Emissions

Basic Facts about U.S. National Ambient Air Quality Standards (NAAQS) The Clean Air Act directs U.S. EPA to identify and set national standards for pollutants with adverse public health and environmental effects. The Clean Air Act also requires EPA to review each standard at least once every 5 years. US EPA established NAAQS for six criteria pollutants: –ozone, carbon monoxide, sulfur dioxide, nitrogen dioxide, lead, and particulate matter (PM)

Setting and Achieving the NAAQS Setting the standards –Health effects –Environmental effects Achieving the standards –Cost –Time needed to attain the standards Key parts of a standard: –Indicator (O 3, PM 2.5, etc.) –Level (e.g., 0.12 ppm, 150 µg/m 3 ) –Averaging time (e.g., 1 hour, 24 hours, annual) –Form (e.g., one exceedance per year, never to be exceeded)

NAAQS Review/Revision Process CASAC: Clean Air Scientific Advisory Committee

Chronology of Photochemical Oxidant (as Ozone) NAAQS Year of Promulgation LevelAveraging Time Form ppm (primary = secondary) HourlyNot to be exceeded more than once per year ppm (primary = secondary) HourlyNot to be exceeded more than once per year ppm (primary = secondary) 8-hr averageThree-year average of the annual fourth highest daily maximum 8-hr average 2007 (proposed)0.06 ppm (primary) 8-hr averageProposed secondary to be below 0.8 ppm in the range of ppm

Ozone NAAQS Attainment Timeline DateProcess July 18, 1997US EPA promulgates ozone NAAQS 2000US EPA designates non-attainment areas 2003States submit Implementation Plans for meeting the eight-hour standard. For areas which haven’t met the current one-hour standard, ongoing efforts are sufficient through the current attainment dates 2012States have up to 10 years to meet NAAQS plus two one-year extensions

Ozone NAAQS timeline for areas classified as “transitional” DateProcess July 18, 1997US EPA promulgates ozone NAAQS 2000States submit Implementation Plans to address transported air pollution. US EPA classifies areas as “transitional.” All new non-attainment areas are eligible to be “transitional.” 2004States achieve reductions from regional sources 2007States assess effectiveness of regional reductions 2012States have up to 10 years to meet NAAQS plus two one-year extensions

Chronology of PM NAAQS Year of Promulgation IndicatorLevel Annual24-hr 1971TSP (Total suspended particulate matter) 75 µg/m 3 (geometric mean) 260 µg/m 3 (primary; not to exceed >1/yr) 150 µg/m 3 (secondary; not to exceed >1/yr) 1987PM µg/m 3 (arithmetic mean) 150 µg/m 3 (not to exceed >1/yr, 3 years) 1997PM µg/m 3 (arithmetic mean) 150 µg/m 3 (99 th percentile averaged over 3 years) PM µg/m 3 (arithmetic mean) 65 µg/m 3 (98 th percentile averaged over 3 years) 2006PM µg/m 3 (arithmetic mean) 35 µg/m 3 (98 th percentile averaged over 3 years) 2006PM 10 None150 µg/m 3 (not to exceed >1/yr, 3 years) 2006 (proposed but rejected) PM (PM coarse ) None70 µg/m 3 (99 th percentile averaged over 3 years)

PM 2.5 NAAQS Attainment Timeline DateProcess July 18, 1997US EPA Promulgates PM 2.5 NAAQS September 16, 1997NAAQS become effective July 1, 1998States submit Monitoring Plans 1998 – 2000Monitors put in place nationwide 1998 – 2003Monitoring data collected 1999US EPA designates areas as “unclassifiable” 2000US EPA completes five-year scientific review of NAAQS 2002US EPA reviews PM 2.5 NAAQS 2002 – 2005US EPA designates non-attainment areas 2005 – 2008States submit Implementation Plans for meeting the NAAQS 2012 – 2017States have up to 10 years to meet NAAQS plus two one- year extensions

Limitations of the U.S. PM 2.5 Standards Causal relationships of PM 2.5 to health not established; only epidemiological relationships 24-hour average masks peak exposures of shorter duration Highest concentrations neglected or attenuated by statistical form Already regulated as a subset of existing PM 10 standard Is not accurately measured by practical Federal Reference Methods (FRMs) under all circumstances Other indicators are more specific to respiratory and cardiovascular effects (several of these are due to available measurement technology)

Why use 98 th Percentile for 24-hr NAAQS? Statistical robustness Statistically significant associations with health effects: –Mortality –Hospital Admissions –Respiratory symptoms

2006 versus 1997 PM 2.5 NAAQS Same levels for primary (health) and secondary (welfare) standards Minor changes in ambient monitoring More stringent spatial averaging requirements More relaxed data completeness requirements Simplification of reporting requirements

PM 2.5 Federal Reference Methods (FRMs) Andersen RAAS Thermo Fisher Scientific, formerly Andersen Instruments, Smyrna, GA URG MASS URG Corp., Raleigh, NC Partisol Sampler Thermo Fisher Scientific, formerly Rupprecht & Patashnick, Albany, NY BGI PQ-200 BGI, Inc., Waltham, MA

PM 2.5 Monitoring Changes Samplers with very sharp cut cyclones (VSCC) would be FRM (had been FEM) Requires improved impactor oil for WINS Time limit to recover samples increased from 96 to 177 hours Allows up to 30 days* to condition and weigh retrieved filters when transit temperature is less than average ambient temperature during sampling *In the past, the number of days was determined by: days=34-T[°C]; T=storage temperature <25 °C

Size-selective Inlets WINS Impactor Very sharp cut cyclone (VSSC)

PM 2.5 Spatial Averaging Changes * Current –Correlation (r) ≥0.6 between monitor pairs –Difference ≤20% between monitor values Proposed –Correlation (r) ≥0.9 between monitor pairs –Difference ≤10% between monitors * Determined on a seasonal basis

PM 2.5 Data Completeness Changes Required ≥75% data completeness per quarter Collocated sampler data can substitute for missing primary sampler data Allow 11 or more samples per quarter if calculated annual standard design value exceeds the NAAQS For a quarter with < 11 samples, allow data substitution of an historically low 24-hr value (to reach 11 samples) if the results yield an annual mean, spatially averaged annual mean, and/or annual standard design value exceeding the NAAQS

PM 2.5 Data Reporting Changes No longer need to report the following parameters to EPA’s Air Quality System (AQS; –Flow rate –Coefficient of Variance –Sample volume –Minimum & maximum temperature –Minimum & maximum pressure Continue to report: –PM 2.5 concentration –Average temperature –Average pressure State and local agencies need to retain information on parameters no longer reported to AQS

Why a Proposed PM Standard? Court decision (D.C. Circuit in 1999 and 2001) –PM 10 composed of PM 2.5 –Need to regulate coarse PM independent of PM 2.5 Recent studies showing PM effects* –Inflammation and aggravation of allergic effects –Coughs in children –Increased hospital admissions *Generally stronger for short-term rather than long term effects

Limitations to the PM Standard Includes any ambient mix of PM dominated by resuspended dust from high density traffic on paved roads and PM generated by industrial sources Excludes any ambient mix of PM dominated by rural dust and soils and PM generated by agricultural and mining sources –Agricultural sources, mining sources and other similar crustal PM dominated sources shall not be subject to control in meeting this standard

Concerns about Proposed Revisions to PM Standards Are levels set to provide an adequate margin of safety to protect sensitive populations, given the quality of the measurement and health effects data? Should a separate short-term standard for PM 2.5 be established based on visibility concerns? Do measurement, characterization, and health-effects studies adequately support the cited differences in toxicity between rural and urban dust? Why not control agricultural, mining and other non-urban dust sources?

For More Information: See the June issue of the Journal of the Air & Waste Management Association for the “Critical Review” by John Bachmann “Will the Circle be Unbroken: A History of the U.S. National Ambient Air Quality Standards.”