Science

New report finds cleaner air for many, but not all

paths to progress

The American Lung Association, which tracks air quality in the United States, says the Clean Air Act is working.

Downtown Los Angeles is shrouded in early morning coastal fog. Despite major improvements in US air quality, L.A. and other California cities are still struggling with high levels of air pollution
Richard Vogel/AP/File
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More Americans have been breathing easy in recent years.

On Wednesday, the American Lung Association (ALA) released its annual “State of the Air” report, which tracks air quality for the years 2013-2015, both nationally and for specific metrics, like cities and types of pollution.

While some areas showed continued improvement and others deterioration, overall the report found that “the number of people exposed to unhealthy levels of air pollution dropped to more than 125 million people," down almost 25 percent from 166 million in the years covered in the previous report (2012 – 2014).

The report credits this progress to the Clean Air Act, one of the US environmental movement’s landmark achievements passed in 1970, and the scientists who study this issue agree. But in some parts of the country – especially California – environmental advocates see a need for smart policy decisions that will continue cleaning the air.

“This [report] is just further evidence that our efforts to clean up the air are working, but that we have to push further to help improve the air ... for everybody in the country,” Chris Cappa, a professor in the department of civil and environmental engineering at University of California–Davis, tells The Christian Science Monitor in a phone interview.

Air pollution in such places as Beijing and New Delhi has made headlines in recent years, but the mid-20th century saw many American cities wrapped in a similar haze. In October 1948, the air over Denora, Penn., got so thick with smog from its steel and wire factory that the industrial town’s fire department handed out oxygen tanks to ailing residents. The pollution killed 20 people and left half of the town's 14,000 residents recovering in hospitals or at home.

A series of policies meant to prevent this disaster from happening again culminated in 1970 with the Clean Air Act’s passage. Under the law, the US Environmental Protection Agency (EPA) must set science-based air quality standards for common types of air quality pollutants, and requires states to set enforceable limits on meeting those standards. Other components of the act cover interstate pollution and mobile emitters, such as car tailpipes.

“While there are other factors” behind the drop, “the Clean Air Act has probably been the most important component,” explains Cort Anastasio, professor in the air, land, and water resources department at UC-Davis, in an email to the Monitor.

“EPA regulations,” he continues, “while regularly derided by some in (and out) of politics, are making our air cleaner and provide benefits (in the form of increased human health) that far outweigh their costs.”

Contrary to concerns that these regulations would stifle businesses, the EPA estimates that just one provision of the act – 1990 amendments that target acid rain – will yield an economic benefit of $2 trillion by 2020, at an enforcement cost of $65 billion. Already, the ALA's report notes that America's gross domestic product has grown by 246 percent since the Act was passed – even as emissions of the six main pollutants it targets have fallen by 71 percent. 

Despite these gains, not everyone is seeing cleaner skies. The ALA found that 18 million Americans “live in 12 counties with unhealthful levels of all three [pollutants tracked in the study]: ozone and short-term and year-round particle pollution.” And even as ozone and year-round particle pollution have dropped, it observed “an unrelenting increase in dangerous spikes in particle pollution.”

For both short-term “spikes” and a year-round presence of dust, smoke, and soot particles, California cities topped the rankings, and some, like Bakersfield in the Central Valley, indeed saw an increase in this type of pollution.

The Golden State’s hill-and-valley topography helps create “thermal inversions,” layers of warm air that trap smog in low-lying areas. While cities like Los Angeles have been grappling with this problem for decades, Professor Anastasio says that recent environmental changes may have driven the latest increase.

“My guess is that the California drought is partially responsible for making fine particle ... pollution worse since 2010,” he writes in an email. “Winter rains clean the air of particles, but we had little precipitation for the past five years, until this year.”

Professor Cappa, his colleague at UC-Davis’s Air Quality Research Center, adds that the drought has brought an increase of wildfires. “We've had a lot of pretty bad fire seasons lately, which can really lead to poor air quality,” he says.

Cappa cautions against making too much of the recent increase. “We want to pay attention to those [spikes],” he explains, “but we don't necessarily want to overly worry right away, because that ... probably is linked to short-term changes in meteorology and climate in the area.”

Both droughts and wildfires, he points out, are linked to climate change, meaning that curbing them could require stemming CO2 emissions. But at the same time, environmental advocate Nayamin Martinez also sees a need for stronger regulations at the local level.

Ms. Martinez serves as director of the Central California Environmental Justice Network (CCEJN); in her group’s view, the San Joaquin Valley Air Pollution Control District, which oversees emissions-reduction plans in Bakersfield, Fresno, and some of the other most-polluted cities, “could be coming up with regulations that are more stringent that could protect our air.”

In a phone interview with the Monitor, Martinez points to one recent success in this effort: Advocacy from CCEJN and other environmental groups convinced California’s Air Resources Board to reject San Joaquin’s plan to reduce particulate pollution, requiring it to come up with a more aggressive one.

In the nation's remaining pollution pockets, the ALA’s research bolsters the case for improvements like these.

When Martinez spoke with the Monitor on Wednesday afternoon, the local ALA chapter had already briefed her on the latest report. “Having this type of national organization coming out with this information really backs up our argument,” she says.