In the United States, the list of current non-attainment areas can be viewed on EPA’s Greenbook website here. As of December 2021, some locations within California and Pennsylvania are listed as non-attainment areas for particulate matter 2.5. If your project is located outside the United States, you’ll need to research data on recorded readings for particulate matter at your project location. If the three-year average of the weighted annual mean for particulate matter exceeds 15 ug/m3, your location is in a non-attainment area.

EPA’s Greenbook may also be referenced to confirm the ozone concentration for projects located in the United States and compare to the prerequisite threshold of 0.100 ppm. In the Area Maps provided on the site, a most recent three-year average, annual fourth-highest daily maximum 8-hour average ozone concentration exceeding 0.100 ppm (195 μg/m3) equates to a US EPA 8-hour ozone classification of “Serious” or higher ("Severe-15", "Severe-17", or "Extreme"). As with particulate matter, projects located outside the United States must find measured data for ozone concentrations at the project location and compare to the prerequisite requirement.