In addition to damaging your lungs, air pollution can harm your brain, accelerating adult cognitive decline and psychological stress.

According to a 2019 study published in the Proceedings of the National Academy of Sciences, the 100,000 Americans who die each year from air pollution are almost as many as those who are killed in car accidents in the country.

Simply put, you should avoid spending a lot of time in areas with high levels of pollution. According to a recent U.S. News and World Report investigation, which classified all 50 U.S. states according to how dirty they are and the risk that pollution poses to people’s health, that is terrible news for a good number of states.

The rankings are based on 2019 data from the U.S. Environmental Protection Agency, which calculated the total hazardous chemical pollution produced in each state as well as the per capita risks of long-term, chronic health impacts, such as cancer and birth defects, in each state.

According to U.S. News & World Report, the measurements took into account the air and water emissions produced by mining, manufacturing, producing electricity, and treating hazardous waste. They excluded minor facilities like auto body shops or dry cleaners as well as pollution from agriculture, transportation, and small businesses.

Starting at the bottom of the list are the seven worst states:

Louisiana

Nevada

Indiana

Delaware

Utah

Ohio

Oregon

It is not surprising that Louisiana came in bottom place. Four of the top ten “super polluter” chemical factories in the United States are located in Louisiana, according to an analysis done in 2020 by the Environmental Integrity Project. In spite of a countrywide decline in the overall number of plants, a 2019 ProPublica investigation discovered that the number of Louisiana facilities with high emissions has climbed since the 1980s.

A January 2022 study from Tulane University found that exposure to excessive levels of air pollution is to blame for at least 85 cancer cases annually in the state.

The American Lung Association assessed Nevada’s air quality as among “the unhealthiest for the most hazardous and widespread types of air pollution” in 2021, cementing the state’s ranking as the second-most polluted state. The cities of Las Vegas and Reno were included on the list of the top 25 most polluted cities by short-term particles, or toxic airborne contaminants, in the same year.

The inclusion of Oregon on the list may come as a surprise: 11 national forests, a national grassland, and even 21 national wildlife refuges are located in the state. According to the website for Oregon, the state’s biggest source of air pollution is cars and trucks, and periodic wildfires only make the state’s poor air quality worse.

According to the ALA, a few Oregon cities are among the worst polluted in the nation.

On the other end of the scale, Vermont was named the least polluted state in the nation by U.S. News and World Report. According to the ALA, the air quality in Vermont’s cities is among the best in the nation, with particularly low concentrations of the most dangerous kinds of air pollution.