Physical Environment

Air pollution was responsible for 7.9 million

deaths worldwide in 2023.³⁷ Particulate matter with a diameter of 10 microns or less (PM₁₀) poses a threat to human health

because it can penetrate deep into lung tissue and enter the bloodstream.³⁸ Exposure to fine particle air pollution has been linked to

heart and lung problems, including decreased lung function, asthma, irregular heartbeat and heart attack.³⁸

Changes over time. Nationally, the average exposure of the general public to particulate matter of 2.5 microns or less, measured in micrograms of fine particles per cubic meter, increased 13% from 7.8 to 8.8 between 2019-2021 and 2022-2024. This increase in air pollution occurred after two decades of continuous improvement, including a historic low during the COVID-19 pandemic (2019-2021).

Between 2019-2021 and 2022-2024, 12 states had increases in air pollution of 13% (the national change) or more.​ The largest increases were: 66% in North Dakota (5.0 to 8.3 micrograms of fine particles per cubic meter), 33% in Connecticut (6.1 to 8.1) and 27% in Michigan (8.2 to 10.4). During the same time period, air pollution decreased 13% or more in five states, led by: ​18% in Colorado (7.3 to 6.0), 17% in Arizona (10.5 to 8.7) and 16% in Alaska (7.0 to 5.9).

Differences. Air pollution varied by geography in 2022-2024, with levels 2.9 times higher in California (11.7 micrograms per cubic meter) than in Wyoming (4.1).

Safe drinking water is important to overall health and can help prevent certain birth defects

, infectious diseases

and exposure to harmful chemicals

.^39–41 Water contaminants such as arsenic, lead and nitrates have been strongly linked to gastrointestinal illnesses

, cancer

and neurodevelopmental damage

in children.^42–44

Changes over time. Nationally, the average number of health-based drinking water violations per community water system decreased 11% from 2.8 to 2.5 between 2023 and 2024. 

Between 2023 and 2024, drinking water violations decreased 11% (the national change) or more in 18 states, led by: 36% in Nebraska (2.8 to 1.8 average violations per community water system), 26% in Texas (3.5 to 2.6), and 25% in both Iowa (2.0 to 1.5) and New Hampshire (2.0 to 1.5).

During the same time period, drinking water violations increased 11% or more in 12 states and the District of Columbia, led by: 90% in Rhode Island (2.9 to 5.5 average violations per community water system), 55% in Arkansas (3.3 to 5.1), 33% in the District of Columbia (1.5 to 2.0), and 20% in Tennessee (1.5 to 1.8), North Dakota (1.0 to 1.2) and Missouri (1.5 to 1.8).

Differences. Drinking water violations ranged from zero in Hawaii to 5.5 average violations per community water system in Rhode Island. 

Unlike fossil fuels, renewable energy

sources are clean and reduce carbon emissions and air pollution.⁴⁵ Generating electricity from clean, sustainable and affordable energy sources can improve health outcomes

by reducing air and water pollutants emitted by coal and natural gas plants.⁴⁶

Changes over time. Nationally, the percentage of electricity generated from renewable sources (wind, solar rays, hydroelectric energy, biomass or geothermal heat) increased 6% from 20.6% to 21.9% between 2023 and 2024. During this period, electricity from solar (4.0% to 5.1%) and wind (10.1% to 10.5%) sources increased 28% and 4%, respectively, while electricity from biomass (0.4% to 0.3%) and hydroelectric (5.9% to 5.6%) sources decreased 25% and 5%, respectively.

Between 2023 and 2024, renewable energy increased 6% (the national change) or more in 27 states, led by: 189% in Mississippi (0.9% to 2.6%), 100% in Louisiana (1.1% to 2.2%) and 41% in Ohio (3.7% to 5.2%).

During the same time period, renewable energy decreased 6% or more in five states, led by: 20% in Maine (54.1% to 43.1%), 13% in Connecticut (3.1% to 2.7%) and 10% in Massachusetts (21.5% to 19.3%).

Differences. Renewable energy varied by geography in 2024. It was 38.4 times higher in Vermont (84.4%) than in Louisiana (2.2%).

Families that struggle to afford housing

may face eviction, foreclosure and homelessness.⁴⁷ Households with housing instability are exposed to increased stress that affects physical and mental health

.⁴⁸ Being homeless puts people at higher risk of health problems

like respiratory infections, diabetes, substance use disorders and associated viruses, and heart and lung disease.⁴⁹ The stress and safety concerns of homelessness also increase risk of mental illnesses

such as anxiety, depression and post-traumatic stress disorder (PTSD).⁴⁹

Changes over time. Nationally, the rate of people experiencing homelessness — based on point-in-time counts conducted on a single night in January each year — increased 16% from 19.4 to 22.6 people per 10,000 population between 2023 and 2024. In 2024, approximately 767,900 people experienced homelessness in the U.S., an increase of 118,300 since 2023. 

Of those who were homeless in 2024, 65% (approximately 496,500 people) were sheltered in transitional housing programs, safe havens or shelters and 35% (271,400 people) were unsheltered, meaning their primary nighttime location was a public or private place not designated for sleeping (cars, public parks, abandoned buildings, bus or train stations, airports, camping grounds, or outside on the street). Between 2023 and 2024, the rate of people experiencing homelessness in shelters increased 24% (11.8 to 14.6 people per 10,000 population), and unsheltered homelessness increased 5% (7.6 to 8.0). During this time, homelessness increased 13% or more in 13 states. The largest increases were 114% in Illinois (9.5 to 20.3), 85% in Hawaii (43.4 to 80.5), and 51% in both New York (52.7 to 79.5) and Massachusetts (27.3 to 41.1).

Differences. Homelessness varied by geography in 2024, with the rate 23.0 times higher in Hawaii (80.5 people experiencing homelessness per 10,000 population) than in Mississippi (3.5).