A new report released this week by the American Lung Association finds fine particle, or soot, pollution continues to improve across West Virginia, but smog pollution remains a challenge.

The American Lung Association’s 20th annual “State of the Air” report analyzed air quality data collected by federal, state and local air monitoring devices between 2015 and 2017, the most recent data available. Data is collected in just 10 of West Virginia’s 55 counties.

The Lung Association’s 2019 report found fine particle pollution continued to improve across the state. All counties with data earned an “A” grade.

Soot pollution is expelled from sources like exhaust pipes or industrial plants. It’s the fine, microscopic dust sometimes small enough to pass directly into the blood streams through the lungs. Not only can it exacerbate respiratory health problems, but fine particle pollution is also linked to heart problems.

Cabell and Kanawha counties had zero unhealthy days of short-term spikes in particle pollution for at least the fifth consecutive year, listing them among the nation’s cleanest counties for soot pollution, the report stated. The area ranked 89 worst in the country.

It was a different story, however, for ozone pollution. Ozone is a powerful lung irritant that exacerbate asthma attacks and negatively impact those with other lung diseases. The new report showed West Virignia counties had similar levels of unhealthy days of high ozone as last year’s report.

Cabell, Kanawha, Ohio and Wood counties all earned “C” grades and had four or more days with unhealthy ozone levels.

The American Lung Association said a warming climate may help explain the boost in unhealthy ozone pollution levels. Ozone levels increased in most cities around the country during the three-year period, which were also some of the warmest on record.

The report also highlighted a series of federal environmental laws that have been rolled back — from methane standards for oil and gas wells to car pollution standards — that may be negatively affecting air quality.

Nationally, the report found ozone and short-term particle pollution worsened in many cities. More than four in 10 Americans, or about 43 percent of the population, live in counties that have monitored unhealthy ozone and/or particle pollution.

This article was originally published by West Virginia Public Broadcasting.