You are here

EH-1 Data Details

Expand All

EH-1 Reduce the number of days the Air Quality Index (AQI) exceeds 100, weighted by population and AQI

Leading Health Indicators are a subset of Healthy People 2020 objectives selected to communicate high-priority health issues.

About the Data

Description of the data source, numerator, denominator, survey questions, and other relevant details about the national estimate.

Data Source: 
Air Quality System (AQS); Environmental Protection Agency (EPA)
Changed Since the Healthy People 2020 Launch: 
Baseline (Year): 
2,203,025,589 (2006–08)
Target-Setting Method: 
10 percent improvement

Weighted days with AQI greater than 100


not applicable

Comparable Healthy People 2010 Objective: 
Adapted from HP2010 objective
Data Collection Frequency: 
Leading Health Indicator:
Environmental Health
Methodology Notes: 

    Steps in the calculation of weighted days with an AQI greater than 100:

    1. For each year in the base period (e.g., for 2008 use 2006, 2007 and 2008), determine the daily AQI values by county.
    2. For days with AQI values over 100, divide the actual AQI value by 100.
    3. Sum these AQI-weighted days by year for each county.
    4. For each county, multiply the sum of yearly AQI-weighted days by the county’s population for a reference year (e.g., 2008).
    5. Average the population-weighted and AQI-weighted value for each county across the three years in the period.
    6. Sum the three-year average population-weighted and AQI-weighted values across all counties to determine the national metric value.
Changes Between HP2010 and HP2020: 
This objective differs from Healthy People 2010 objectives 08-01a through 08-01f in that the Healthy People 2010 objectives tracked all six Criteria Air Pollutants (CAP) separately: Ozone, Particulate Matter, Carbon Monoxide, Nitrogen Oxides, Sulfur Dioxide, and Lead. This objective combines the two CAP (Ozone and Particulate Matter) responsible for over 95% of poor air quality days into a single Air Quality Index (AQI).

Revision History

Any change to the objective text, baseline, target, target-setting method or data source since the Healthy People 2020 launch.

Description of Changes Since the Healthy People 2020 Launch: 
In 2012, the measure was changed from a standardized (by resident population of AQI counties) to an unstandardized measure. As a result, the original baseline of 10.85 days (2006-08) was revised to 2,200,000,000 days (2006-08). The target was adjusted from 9.76 days to 1,980,000,000 to reflect the revised baseline using the original target-setting method. The baseline was revised from 2,200,000,000 to 2,203,025,589 to reflect the unrounded data EPA is now reporting. The target was changed from 1,980,000,000 to 1,982,723,030 to reflect a 10% improvement since baseline.


Additional resources about the objective

  1. Monitoring air quality to reduce health risks