PARTICULATE ISSUES FOR WESTERN STATES: NEW STANDARDS, OLD PROBLEMS

• Jurisdiction: United States

Air Quality Challenges Facing the Natural Resources Industry in the Western United States
(Nov 2007)
CHAPTER 6A
PARTICULATE ISSUES FOR WESTERN STATES: NEW STANDARDS, OLD PROBLEMS
Joseph P. Mikitish
Arizona Attorney General's Office
Phoenix, Arizona

Background

In 2006, EPA adopted new standards for particulate matter with a diameter of 2.5 microns or less.¹ These pollutants, often referred to as fine particulate, PM 2.5, or soot, are a mixture of extremely small particles and liquid droplets that, when breathed in, can reach deep into the lungs.²

Particulate pollution been linked to a variety of significant health problems including aggravated asthma, chronic bronchitis, reduced lung function, irregular heartbeat, heart attacks, and premature deaths.³ Children, senior citizens, and people with existing lung and heart diseases (including diabetes), are more susceptible to harm from PM 2.5 than the rest of the population.⁴ These subgroups of sensitive populations add up to more than a hundred million people (more than a third of the U.S. population): 22 million Americans have been diagnosed with heart disease, 39 million with hypertension, almost 12 million with diabetes, 9 million with chronic bronchitis, 3 million with emphysema, while almost 19 million adults and 9 million children have chronic asthma.⁵ In addition, about 38 percent of the U.S. population is either under 18 years of age or 65 or older.⁶

The new EPA rule tightens the 24-hour PM 2.5 standard from 65 micrograms per cubic meter (µg/m³) to (µg/m³).⁷ EPA decided to retain the existing annual standard of 15 (µg/m³) in the new rule. Each of those decisions currently is being challenged in the Federal Court of Appeals for the District of Columbia.⁸

EPA adopted the new fine particulate standards after conducting an extensive review of scientific studies on the impact of particulates on public health and welfare. These studies highlighted a broader level of understanding of the nature and level of health concerns, and the significant risks from short-term exposure to lower level of fine particulate pollution.⁹ The new standards are one more part of the effort to reduce particulate pollution, including the Clean Air Interstate Rule (CAIR) that reduces particulate pollution emissions from power plants in the eastern portion of the United States; the Clean Diesel Program that reduces emissions from highway, nonroad, and

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stationary diesel engines; and the Clean Air Visibility Rule that aims to reduce particulate emissions affecting visibility and National Parks and Wilderness Areas.¹⁰

In the spring of 2007, EPA finalized the clean air fine particle implementation rule that establishes the requirements for states to implement the fine particle pollution standards.¹¹ The implementation rule also designated areas that attain and do not attain the fine particle standards. Thirty-nine areas across the country, most in the East, have been designated as nonattainment for the fine particle standards.¹²

Concerns for the West

While fine particulates are a larger issue in the East, they clearly also cause problems in the West. Large portions of California along with portions of Idaho, Montana, New Mexico, Oregon, Utah, and Washington, are not in the attainment with the newly adopted 24-hour or existing annual standards.¹³ While diesel soot and other mobile source primary emissions, and soot from fires are a major component of fine particulates, much of the root cause is secondary - formed from gaseous pollutants SO_x and NO_x. Over half of the PM2.5 in the east is sulfate from fossil fuel combustion, mostly coal fired power plants. Much of it is transported from the Midwest and the Ohio Valley. The rest is mostly mobile source related; soot and nitrate formed from NO_x. By comparison, Western PM2.5 is not as homogeneous - some places are dominated by mobile and stationary source combustion emissions (e.g., So Cal...