Great health benefits from new US air quality standards

New air quality standards announced by the EPA are estimated to yield health benefits in the USA of between 13 and 100 billion dollars.

On 25 January, the United States Environmental Protection Agency (EPA)announced a new national air quality standard for nitrogen dioxide, and earlier that month EPA also proposed a strengthening of the nation’s standards for ground-level ozone.

Currently there are National Ambient Air Quality Standards (NAAQS) in effect in the US for six pollutants, namely: particulate matter, ozone, sulphur dioxide, nitrogen dioxide, lead, and carbon monoxide. For each of these, EPA must set standards sufficiently protective of both public health and public welfare.

The Clean Air Act requires EPA to review and, if necessary, revise the standards every five years – a requirement the agency has repeatedly failed to abide by. But this is now changing as the Obama administration is making the NAAQS programme a higher priority.

According to the EPA, the new one-hour standard for nitrogen dioxide (NO2) will protect millions of Americans from peak short-term exposures, which primarily occur near major roads. Short-term exposures to NO2 have been linked to impaired lung function and increased respiratory infections, especially in people with asthma.

“For the first time ever, we are working to prevent short-term exposures in high risk NO2 zones like urban communities and areas near roadways,” said EPA Administrator Lisa Jackson. “Improving air quality is a top priority for this EPA.”

While establishing a new one-hour standard for NO2 at a level of 100 parts per billion (ppb), the EPA is also retaining the existing annual average standard of 53 ppb. NO2 is formed from vehicle, power plant and other industrial emissions, and contributes to the formation of fine particle pollution and ozone smog.

The American Lung Association, welcomed the new standard, calling it a good first step, but said the EPA’s original proposal last summer was more protective. “After waiting 38 years, we had frankly hoped for a stronger, more protective standard. Their decision allows areas to have NO2 concentrations that remain hazardous to the millions of people who will have to breathe them,” said Charles Connor, president of the ALA.

Connor made reference to a recent review by the Health Effects Institute. An expert panel concluded that breathing NO2 and other pollutants from highway traffic increased the risk that a child’s asthma would get worse. Strong evidence warned that pollution from traffic may even increase the risk that children could develop asthma, or worsen their lungs’ ability to function. For older adults and people with cardiovascular disease, living near a highway may increase the risk of early death, the review showed.

The Institute’s report states, “Based on a synthesis of the best available evidence, the Panel identified an exposure zone within 300–500 meters from a highway or major road as the area most highly affected by traffic emissions and estimated that 30–45 per cent of people living in large North American cities live within such zones.”

On January 7, the EPA presented its proposal for new ozone standards. A “primary” standard to protect public health, was suggested to be set at a level between 60 and 70 ppb measured over eight hours. The current standard is 75 ppb.

Ground-level ozone, also known as smog, is linked to a number of serious health problems, ranging from aggravation of asthma to increased risk of premature death in people with heart or lung disease. Ozone can even harm healthy people who work and play outdoors.

EPA is also proposing to set a separate “secondary” standard to protect the environment, especially plants and trees. This seasonal standard is designed to protect plants and trees from damage occurring from repeated ozone exposure, which can reduce tree growth, damage leaves, and increase susceptibility to disease.

Depending on the level of the final standard, the proposal would yield health benefits between US$13 billion and 100 billion, according to the EPA. The new standard would help reduce premature deaths, aggravated asthma, bronchitis cases, hospital and emergency room visits and days when people miss work or school because of ozone-related symptoms. Estimated costs of implementing this proposal range from US$19 billion to 90 billion.

The EPA is scheduled to issue final ozone standards in August 2010, and it expects to propose new fine particulate (PM2.5) standards in July 2010 and finalize them by April 2011. A new one-hour sulphur dioxide (SO2) standard was proposed in November 2009.

Christer Ågren

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Note: For comparing air quality standards expressed in parts per billion (ppb) with those expressed in micrograms per cubic metre (µg/m3), the following conversion factors could be used: 1 ppb NO2 = 1.91 µg/m3 NO2 and 1 ppb O3 = 2 µg/m3 O3.

The US Clean Air Act and EPAIn setting primary ambient air quality standards, EPA’s responsibility under the law is to establish standards that protect public health, regardless of the costs of implementing a new standard. The Clean Air Act requires EPA, for each criteria pollutant, to set a standard that protects public health with “an adequate margin of safety.” As interpreted by the EPA and the courts, the Clean Air Act requires EPA to create standards based on health considerations alone.

According to the EPA, however, this does not mean that costs or other economic considerations should be ignored – consideration of costs and benefits is essential to making efficient, cost-effective decisions for implementation of air quality standards.

The impacts of cost and efficiency are considered by states, as they decide what timelines, strategies, and policies are most appropriate. Therefore, the Regulatory Impact Analyses produced by the EPA are intended to inform the public about the potential costs and benefits associated with a hypothetical scenario that may result when new air quality standards are implemented, but they are not relevant to establishing the standards themselves.


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