Change in the air

Craig Czarnecki and Lindsay Haas

THOMAS MEYERWisconsin has the Clean Air Act to thank for ensuring fresh, clean air at spaces such as Black Earth Rettenmund Prairie State Natural Area.

Step outside today and take a breath. This is some of the cleanest air Wisconsin has had in decades.

A landmark piece of environmental legislation passed 50 years ago, the Clean Air Act, is largely responsible for the quality of the air we breathe today. Considered to be one of the more successful and comprehensive of all federal laws, the Clean Air Act set in motion an extensive series of successful environmental protection programs that continue to benefit citizens today.

The early 20th century was marked by a series of air pollution events that escalated as new technologies led to greater electricity consumption, increased industrial production and a more automobile-based society. Following extensive public concerns regarding air pollution throughout the 1960s — and concurrent with the growth of the environmental movement — in 1970, Congress passed the Clean Air Act.

This law, along with significant amendments to the act passed in 1990, put into place a wide range of state and federal regulatory programs to improve the quality of the nation’s air.

This included setting national health-based standards for air quality, establishing air permitting requirements, authorizing regulations to limit air pollutant emissions from industrial facilities and motorized vehicles, and ensuring protection of visibility.

Many actions we take for granted today, such as cleaner-burning vehicles and pollution controls on power plants, are thanks to the Clean Air Act.

ENVIRONMENTAL SUCCESS STORY

DNR FILESThe haze of air pollution hangs over Milwaukee's skyline, seen from an airplane circa 1980.

Since the passage of the Clean Air Act, the combined emissions of six common pollutants referred to in the act as criteria pollutants have dropped by 74% across the United States. Those are: particulate matter, sulfur dioxide, nitrogen oxides, volatile organic compounds, carbon monoxide and lead.

Emissions of mercury and other toxic pollutants also have dropped substantially. These improvements occurred while the U.S. population and energy use increased, the economy continued to grow and Americans drove more miles than ever before.

These changes had a major impact on the overall health of people across the country. According to the U.S. Environmental Protection Agency, from 1970 to 2020, the Clean Air Act prevented more than 435,000 premature deaths and prevented millions of cases of disease and sicknesses. Overall, the health benefits of the Clean Air Act have outweighed its costs by more than 30 to 1.

Although national in its impact, the Clean Air Act has undeniably helped improve the air quality in Wisconsin. To take just a few examples:

• Emissions of air pollutants have significantly decreased. Due to acid rain controls and other programs, for example, emissions of sulfur dioxide from power plants and industry have decreased by 90% since 1999. Efforts to control emissions from mobile sources like cars and trucks, as well as large industrial facilities and power plants, reduced emissions of the two compounds that form ozone — oxides of nitrogen (NOx) and volatile organic compounds (VOCs) — by 50% in just the 12 years since 2002. Particulate matter emissions from industrial operations, combustion sources and open burning also have decreased over the last few decades.
• Vehicles are polluting less. EPA initiatives to reduce air pollution from heavy-duty trucks and passenger vehicles have greatly reduced emissions from highway vehicles. Carbon monoxide, NOx, and VOC emissions in Wisconsin decreased significantly from 1970 to 2018 due to new vehicle standards — despite a doubling in the number of miles Wisconsinites traveled during that time.
• More people are breathing healthy air. The portion of the state exceeding federal air quality standards has shrunk over the years, even as the standards themselves have become increasingly stringent. In the early 1980s, more than half of Wisconsinites lived in an area violating at least one air quality standard. Now, about 94% of the state population lives in areas that meet all air quality standards.

LOOK TO THE FUTURE

ZOE SPROUTActions taken since passage of the Clean Air Act have resulted in reduced pollution and improved air quality in Milwaukee today.

Over the past 50 years, the Clean Air Act has dramatically improved air quality and human health throughout the state, yet there is still much to accomplish. The coming years will see the DNR turn to the Clean Air Act to address challenges both old and new, including:

• Responding to climate change. The response to this challenge is one of the defining issues for this generation. Reducing greenhouse gas emissions, moving toward a cleaner automotive fleet and encouraging more efficient use of energy are just some of the ways the act will be used to help address human impact on the climate. At the state level, Gov. Tony Evers has signed a pair of executive orders to address climate change. Executive Order #52 has created the Governor’s Task Force on Climate Change, while Executive Order #38 aims to have Wisconsin utilities carbon-free by 2050.
• Addressing PFAS. Per- and polyfluoroalkyl substances (PFAS) are a large group of human-made chemicals used in industry and consumer products worldwide since the 1950s. Exposure to certain PFAS may increase the risk of adverse health effects, such as thyroid disease, low birth weights and cancer. PFAS can be emitted into the air as vapors or fine particles, but there are currently no federally approved sampling methods for PFAS compounds in ambient air. Understanding how PFAS reacts and moves in the air, determining where and how PFAS is emitted, and developing strategies to address the issue all pose new challenges.
• Solving lakeshore ozone challenges.  While ozone levels across the state have decreased dramatically over the last few decades, some areas along Wisconsin’s Lake Michigan shoreline continue to experience ozone levels above federal standards. Determining how and where to reduce regional ozone-causing emissions further, and from which sources, is an ongoing challenge. Understanding more about the science of ozone formation and transport in the region will help.
   

The Clean Air Act has been a resounding success for 50 years. As a result, Wisconsin residents are fortunate to breathe air every day that is clean to a degree once unimaginable.

In the decades to come, the DNR will continue to rely on this landmark piece of legislation to ensure that future generations of Wisconsinites have access to clean, healthy air.

Craig Czarnecki and Lindsay Haas are members of the DNR Air Program Outreach Team.