Graham Kilmer

Wisconsin Air Is Getting Cleaner

Nearly 20 years of steady reductions in harmful air pollutants.

By - Oct 27th, 2020 10:17 am
Oak Leaf Trail. Photo by Dave Reid.

Oak Leaf Trail. Photo by Dave Reid.

For approximately two decades, the air quality in Wisconsin has been steadily improving.

In order to combat the detrimental effects that hazardous air pollutants have on human health, the U.S. Congress passed the Clean Air Act of 1970, laying the framework for national air quality standards.

These standards have led to reduction in air pollutants that are harmful to respiratory, neurological and cardiovascular health.

The state Department of Natural Resources (DNR) has issued its latest Wisconsin Air Quality Trends Report with data from 2001 to 2019, and shows that since monitoring began, the entire state has seen a steady decline of nearly all major air pollutants. The report found that 95% of the state lives in areas that are below the maximum federal levels for air pollutants.

The report analyzed both direct pollutants and the precursors to pollutants — which create pollution when they react with other compounds in the air.

All the major pollutants in this report contribute to increased risk for a number of illnesses and health problems. And every one, except lead, directly contributes to an increased risk for asthma.

One of the major pollutants, ozone, has been a source of trouble for communities along the eastern shoreline of Lake Michigan. Lakeshore communities have struggled with ozone levels above the standards set by the Environmental Protection Agency. In 2018, parts of six different counties along the lake were found to be above federally accepted ozone levels.

In the upper-atmosphere, ozone is good. It’s what helps block out harmful UV-rays from the sun. At ground level, ozone can be extremely harmful. According to the report, ozone can “lead to or exacerbate numerous health issues, including chest pain, coughing, throat irritation, and airway inflammation. It can reduce lung function and worsen bronchitis, emphysema and asthma.”

The problem here originates in states to the south. When the wind is coming from a southerly direction, ozone precursors are blown over Lake Michigan, where reactions occur producing high levels of ozone. Then, as the sun warms the ground throughout the day, a pressure change occurs causing a lake breeze, blowing all the ozone massing above the lake into coastal communities.

However, Milwaukee has been an outlier in recent years with this trend. The DNR has recorded ozone levels below federal limits in this metro area. Whereas communities to the south and north along the lake have struggled. Ozone levels in the Sheboygan-Kohler Andrae region are regularly some of the highest in Wisconsin.

Concerning all other major air pollutants tracked by the state, excepting sulfur dioxide, Wisconsin has seen declines while it continues to remain below federally accepted levels.

The pollutants measured include particulate matter — very small solid or liquid droplets that cannot be seen but impair visibility. And Nitrogen Dioxide, a precursor to ozone produced primarily by vehicle emissions, which can lead (with long-term exposure) to a heightened risk for acute respiratory illness and inhibited lung development in children. Another pollutant is carbon monoxide, which also comes primarily comes from vehicle emissions. As for lead, it poses well-known health risks to the development and neurological systems of children, who can be exposed to it through paint chips, the soil and lead pipes used for drinking water. But lead is also found in the air, with most of it emitted from from jet fuel and industrial metal processing.

Sulfur dioxide, which largely comes from power plant emissions, has wide ranging negative effects on the respiratory system. And Outagamie County was the only county in the state that did not meet federal standards for this in the latest DNR report. However, between 2002 and 2017, sulfur dioxide was still down 89% across the state.

Read the DNR report here.

Categories: Environment, Weekly

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