Air quality: Merging policy and climate change research

September 30, 2014 |

city bus emissions
Emissions from a Madison Metro bus. (WI DNR photo)

Pedestrians and bicyclists from Delhi and Beijing, Los Angeles and Mexico City know the feeling: itchy eyes, inflamed and congested lungs, coughs and nausea—the caustic sensations that come from breathing polluted air.

Here in Wisconsin, we rarely experience the effects of severe air pollution. But they are not completely unfamiliar, particularly during long, hot summer days when the air stops moving and pollutants from automobile exhaust and industrial effluents accumulate in stagnant air. Powdery-fine particles that include sulfur dioxide can react with moisture in the air to form sulfuric acid, and nitrogen oxides react in sunlight to form ozone. Breathing these pollutants can cause health concerns ranging from mild irritation to a trip to the hospital or even death.

Despite Wisconsin’s success in lowering sulfur and nitrogen emissions from power plants and automobiles, air pollution remains a major concern for health officials in the state and across the U.S. Those concerns are rising as extended heat waves due to climate change are beginning to undermine air quality gains.

Air Policy Metrics and Models

When it comes to public policy and cleaner air in Wisconsin, what’s really going to make a difference? New research published by Tracey Holloway and her UW-Madison colleagues examines the reduction in emission levels when electric utilities shift to lower-carbon strategies such as solar, wind or biomass.

Tallying up pollutants in our skies (carbon dioxide, sulfur dioxide and nitrogen oxides in particular) is one way to evaluate the effectiveness of policies. But the skies of the future will tell the story, so researchers use models to make predictions. Holloway and collaborator Paul Meier of the Wisconsin Energy Institute linked several specialized models to create a snapshot of the future.

Each model mimics different aspects of pollution, such as costs associated with alternate electricity sources, chemical emissions from power plants and other sources, and the movement and chemistry of air pollution in the atmosphere. They also used measured data from 2008 to confirm that model predictions concur with respect to power plant performance and observed air quality.

Using five Wisconsin power plants as single point sources for pollution, Holloway and her colleagues compared a ‘business as usual’ scenario—we keep doing what we’re doing today—with one that incorporates the carbon-reducing recommendations of former Governor Jim Doyle’s Task Force on Global Warming, which issued its final report in 2008. Additionally, the researchers examined whether summer policies, when electricity demand peaks, should differ from winter polices.

The coupled models indicate that policy changes do have an effect on emissions, and could reduce future power plant emissions of sulfur and nitrogen by 33 percent relative to business-as-usual. But air pollution mixes and chemically reacts over wide areas, so even major state reductions would have a minor impact on particulates and ozone. The researchers conclude that lower-carbon electricity can only improve air quality if emission reductions are regional and policies are seasonally tailored.

The paper appeared online in the 26 April 2014 issue of Atmospheric Environment.

“Air quality is separate from climate change,” says Tracey Holloway, a professor of environmental studies at UW-Madison and a member of the Wisconsin Initiative on Climate Change Impacts (WICCI). “But more and more over the past decade, air pollution has been merging with climate change research and policy.”

Sulfur pollution is lower than it was 30 years ago due to the use of scrubbers in coal-fired power plant stacks. Between 1980 and 2005, sulfur dioxide emissions fell dramatically, and in the past decade that number was cut in half again. Similar strides are true for other pollutants including lead, nitrogen oxides, ozone and particulates.

“The U.S. is spending $50 billion a year to control emissions since Clean Air Act regulations were enacted in the 1970’s—getting about $10 in health savings for every $1 spent on emission controls,” says Holloway. “Air pollution is a success story, with our air continually getting cleaner—it is on the upswing.”

Climate change threatens that progress, according to a number of reports, including new research by climate modelers at Stanford University that suggests that the world’s atmospheric circulation patterns may slow with climate change, plunging many highly populated regions into prolonged stagnant air days—another one of the many interacting factors that contribute to bad air quality.

air pollution haze
Milwaukee aerial view showing haze. (WI DNR photo)

When a person inhales air pollutants such as ozone and particulates, they can travel deep into the lungs. Though each affect the body in a different way, health problems include heart and lung disease, respiratory infections and strokes.

Epidemiologists have found clear links between high air pollution days and hospital visits, explains Holloway. For example, during the 1996 summer Olympic Games in Atlanta -- a rare case during which traffic and its associated pollution were drastically reduced -- the number of asthma attacks in the city also dropped.

According to the World Health Organization, poor air quality causes 3.7 million premature deaths per year, numbers health officials warn will climb if climate change continues at its current rate.

“The reason air quality in China and India is so bad is because fossil fuels are burned without the controls required here in the United States,” says Holloway. “But even here in Wisconsin we have days above the limit deemed healthy by the World Health Organization, the Environmental Protection Agency (EPA) and the American Lung Association.”

Holloway adds that the EPA is concerned about the potential impact of climate change on county-level compliance with air quality standards.

Lessons learned from clean air efforts could serve as a nice example for tackling climate change, Holloway speculates -- efforts that could rapidly improve conditions because of the innovation in energy technologies and conservation since the 1970s.