See Methodology for a full explanation of data sources and calculations made for state grades.
Notes for state grades tables:
Not all counties have monitors for either ozone or particle pollution. If a county does not have any monitors for either pollutant, that county’s name is not on the list in these tables. The decision about monitors in the county is made by the state and the U.S. Environmental Protection Agency, not by the American Lung Association.
INC (Incomplete) indicates that monitoring is underway for that pollutant in that county, but that the data are incomplete for all three years.
DNC (Data Not Collected) indicates that data on that particular pollutant is not collected in that county.
The Weighted Average (Wgt. Avg) was derived by adding the three years of individual level data (2018-2020), multiplying the sums of each level by the assigned standard weights (i.e. 1=orange, 1.5=red, 2.0=purple and 2.5=maroon) and calculating the average. Grades are assigned based on the weighted averages as follows: A=0.0, B=0.3-0.9, C=1.0-2.0, D=2.1-3.2, F=3.3+.
The Design Value is the calculated concentration of a pollutant based on the National Ambient Air Quality Standard for PM2.5, which is 12 µg/m3. Counties with design values of 12 or lower received a grade of “Pass” for Annual PM2.5. Counties with design values of 12.1 or higher received a grade of “Fail.”
Notes for at-risk groups tables:
Total Population is based on 2020 U.S. Census and represents the at-risk populations in counties with ozone or PM2.5 pollution monitors; it does not represent the entire state’s sensitive populations.
Those 18 & under and 65 & over are vulnerable to ozone and PM2.5. Do not use them as population denominators for disease estimates—that will lead to incorrect estimates.
Pediatric asthma estimates are for those under 18 years of age and represent the estimated number of people who had asthma in 2020 based on the state rates when available or national rates when not (Behavioral Risk Factor Surveillance System, or BRFSS), applied to county population estimates (U.S. Census).
Adult asthma estimates are for those 18 years and older and represent the estimated number of people who had asthma during 2020 based on state rates (BRFSS) applied to county population estimates (U.S. Census).
COPD estimates are for adults 18 and over who had ever been diagnosed with chronic obstructive pulmonary disease, which includes chronic bronchitis and emphysema, based on state rates (BRFSS) applied to county population estimates (U.S. Census).
Lung cancer estimates are for all ages and represent the estimated number of people diagnosed with lung cancer in 2018 based on state rates (StateCancerProfiles.gov) applied to county population estimates (U.S. Census).
Cardiovascular disease estimates are for adults 18 and over who have been diagnosed within their lifetime, based on state rates (BRFSS) applied to county population estimates (U.S. Census). CV disease includes coronary heart disease, stroke and heart attack.
Pregnancy estimates are for females 18-49 and based on state rates of pregnancies resulting in live births applied to population estimates (U.S. Census).
Poverty estimates include all ages and come from the U.S. Census Bureau’s Small Area Income and Poverty Estimates program. The estimates are derived from a model using estimates of income or poverty from the Annual Social and Economic Supplement and the Current Population Survey, 2020. Puerto Rico poverty estimates come from the U.S. Census Bureau’s American Community Survey, 2015-2019.
People of color are defined as anyone Hispanic or non-Hispanic Black, Asian, American Indian/Alaska Native, Native Hawaiian and Other Pacific Islander, or two or more races and are based on 2020 county population estimates (U.S Census).
Adding across rows does not produce valid estimates. Adding the at-risk categories (asthma, COPD, poverty, etc.) will double-count people who fall into more than one category.
Did You Know?
More than 4 out of 10 people live where the air they breathe earned an F in State of the Air 2021.
150 million people live in counties that received an F for either ozone or particle pollution in State of the Air 2020.
More than 20.8 million people live in counties that got an F for all three air pollution measures in State of the Air 2020.
Breathing ozone irritates the lungs, resulting in something like a bad sunburn within the lungs.
Breathing in particle pollution can increase the risk of lung cancer, according to the World Health Organization.
Particle pollution can also cause early death and heart attacks, strokes and emergency room visits for people with asthma and cardiovascular disease.
Particles are smaller than 1/30th the diameter of a human hair. When you inhale them, they are small enough to get past the body's natural defenses.
Ozone and particle pollution are both linked to increased risk of lower birth weight in newborns.
Do you live near, or work on or near a busy highway? Pollution from the traffic may put you at greater risk of harm.
People who work or exercise outside face increased risk from the effects of air pollution.
Millions of people are especially vulnerable to the effects of air pollution, including infants, older adults and people with lung diseases like asthma.
People of color and those earning lower incomes are often disproportionately affected by air pollution that put them at higher risk for illnesses.
Air pollution is a serious health threat. It can trigger asthma attacks, harm lung development in children, and can even be deadly.
You can protect your family by checking the air quality forecasts in your community and avoiding exercising or working outdoors when the unhealthy air is expected.
Climate change enhances conditions for ozone to form and makes it harder to keep ozone from forming.
Climate change increases the risk of wildfires that spread particle pollution and ozone in the smoke.
This Administration is trying to roll back or create loopholes in core healthy air protections under the Clean Air Act. The Lung Association opposes these actions that will add pollution to the air we breathe.
Cutting air pollution through the Clean Air Act will prevent at least 230,000 deaths and save $2 trillion annually by 2020.