Air pollution in Dallas-Fort Worth may be a problem. But is it unhealthy to breathe?

The Dallas-Fort Worth-Arlington metroplex experienced moderate to bad air days nearly 47% of the time in 2021, according to the Environmental Protection Agency’s air quality data.

Nearly 9% of the time, metroplex air quality was deemed unhealthy. This means that “some members of the general public may experience health effects and members of sensitive groups may experience more serious health effects,” a report from USAFacts says. There was good air quality in DFW 54% of days that year.

DFW measured at 49 in the median air quality index, falling in the “good” range from 0-50, meaning air quality was satisfactory and air pollution posed little or no risk. An air quality rating of 51-100 is moderate, which means that air quality is acceptable but there may be a risk for some people who are unusually sensitive to air pollution. Any number over 100 is unhealthy to varying degrees, ranging from health effects only on sensitive groups to an emergency health warning affecting everyone, termed “hazardous.”

Unhealthy air is concentrated in the western and southwestern U.S., the report found. Phoenix-Mesa-Scottsdale metro area in Arizona had the worst air quality in the country, followed by Riverside-San Bernardino-Ontario, Bakersfield and Visalia-Porterville in California.

Elsewhere in Texas, Houston was ranked sixth among the 10 worst places to live in the U.S. if you want clear air, according to an analysis by The Guardian looking at U.S. areas that have the worst air pollution. Others were Bakersfield, South LA, South and West Chicago, Northwest Indiana, Central Indianapolis, St. Louis, Central Pennsylvania, Central Atlanta and Central Birmingham.

The American Lung Association’s State of the Air report for 2023 graded Tarrant County an F grade on ozone air pollution or smog, which is a powerful lung irritant. It received a B on short-term spikes in particle pollution and passed on year-round exposure to particle pollution.

The report found that DFW had the 18th worst ozone pollution in the U.S. out of 227 metros and 55th worst for annual particle pollution. It was also ranked number 100 for 24-hour particle pollution. Houston had the 9th worst ozone pollution and El Paso had the 14th worst, while San Antonio came in at 23. Houston, McAllen and Laredo also ranked in the 23 metropolitan areas with the most year-round particle pollution.