Understanding the Grades and Tables

A full explanation of the sources of data and methodology is in Methodology.

 Understanding the Grades

  1. Not all counties have monitors for either ozone or particle pollution. If a county does not have a monitor, data on pollution will not show up in these tables. The decision about placing monitors in the county is made by the state and the U.S. Environmental Protection Agency, not by the American Lung Association.
  2. INC (Incomplete) indicates that monitoring is underway for that pollutant in that county, but that the data are incomplete for all three years. Those counties are not graded or received an Incomplete.
  3. DNC (Data Not Collected) indicates that data on that particular pollutant is not collected in that county.
  4. The Weighted Average (Wgt. Avg) was derived by adding the three years of individual level data (2012-2014), 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+.
  5. The Design Value is the calculated concentration of a pollutant based on the form of the National Ambient Air Quality Standard, and is used by EPA to determine whether the air quality in a county meets the standard. The numbers refer to micrograms per cubic meter, or µg/m3.  Design values for the annual PM2.5 concentrations by county for the period 2012-2014 came from data posted on August 19, 2015, through EPA's website. The 2012-2014 design values were compared to the 2012 National Ambient Air Quality Standard for Annual PM2.5, particularly to the EPA's assessment of data quality required, as discussed on EPA's website here. Many design values are missing because state data did not meet quality requirements.   
  6. The annual average National Ambient Air Quality Standard for PM2.5 is 12 µg/m3. Counties with design values of 12 or lower received a grade of "Pass." Counties with design values of 12.1 or higher received a grade of "Fail."

Understanding the Population Tables

  1. Total Population is based on 2014 US 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.
  2. 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.
  3. Pediatric asthma estimates are for those under 18 years of age and represent the estimated number of people who had asthma in 2014 based on the state rates (Behavioral Risk Factor Surveillance System, or BRFSS), applied to county population estimates (U.S. Census).
  4. Adult asthma estimates are for those 18 years and older and represent the estimated number of people who had asthma during 2014 based on state rates (BRFSS) applied to county population estimates (U.S. Census).
  5. 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).
  6. 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, hypertension, stroke, and heart attack.
  7. Diabetes 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).
  8. 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, 2014.
  9. Adding across rows does not produce valid estimates, as it will double-count people who fall into more than one category.

Did You Know?

  1. More than 4 out of 10 people live where the air they breathe earned an F in State of the Air 2017.
  2. More than 125 million people live in counties that received an F for either ozone or particle pollution in State of the Air 2017.
  3. More than 18 million people live in counties that got an F for all three air pollution measures in State of the Air 2017.
  4. Breathing ozone irritates the lungs, resulting in something like a bad sunburn within the lungs.
  5. Breathing in particle pollution can increase the risk of lung cancer, according to the World Health Organization.
  6. Particle pollution can also cause early death and heart attacks, strokes and emergency room visits for people with asthma, cardiovascular disease and diabetes.
  7. 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.
  8. Ozone and particle pollution are both linked to increased risk of lower birth weight in newborns.
  9. Do you live near, or work on or near a busy highway? Pollution from the traffic may put you at greater risk of harm.
  10. People who work or exercise outside face increased risk from the effects of air pollution.
  11. Millions of people are especially vulnerable to the effects of air pollution, including infants, older adults and people with lung diseases like asthma.
  12. People of color and those earning lower incomes are often disproportionately affected by air pollution that put them at higher risk for illnesses.
  13. Air pollution is a serious health threat. It can trigger asthma attacks, harm lung development in children, and can even be deadly.
  14. 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.
  15. Big polluters and some members of Congress are trying to change the Clean Air Act and dismantle 47 years of progress. The Lung Association is fighting to keep the law strong to continue to protect public health.
  16. Cutting air pollution through the Clean Air Act will prevent at least 230,000 deaths and save $2 trillion annually by 2020.
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