What Is the Air Quality in Billings, North Dakota?

Billings, North Dakota earns a C — air quality is fair, but not great. With a 5-year median AQI of 37, the city sees a meaningful number of "Moderate" days each year, when the EPA flags air as a concern for unusually sensitive people.

Billings, North Dakota's 5-year median AQI of 37 is 4 points below the national average of 41 — meaningfully cleaner than the typical U.S. metro tracked here. Within North Dakota, Billings, North Dakota's air quality is roughly typical for the state, where the average city posts a 5-year median AQI of 37.

For context within North Dakota: Williams, North Dakota currently holds the state's cleanest grade (B, AQI 34), while Ward, North Dakota sits at the bottom (C, AQI 36).

Air quality in Billings, North Dakota has held roughly steady over the past decade, with year-to-year shifts in median AQI of less than half a point. That stability makes the city's long-run grade a reliable signal of what residents can expect day-to-day.

In 2014, Billings, North Dakota posted a median AQI of 36. By 2023 that figure was 39 — a rise of 3 AQI points dirtier across 10 years of EPA records.

Across the past five years, this area has logged just 15 days where AQI rose into the "Unhealthy for Sensitive Groups" range or worse — about 3 days per year, or roughly one every other month. That is a low count by national standards.

Healthy adults can continue normal outdoor activity in most weather, but should pay attention to AQI alerts during the worst pollution windows. People with asthma, heart disease, or pregnancy should reduce prolonged or intense outdoor exertion on flagged days, and consider running an indoor HEPA air cleaner during peak season. Because ozone peaks in the afternoon on hot sunny days, plan outdoor exercise for early morning or after sunset on bad-air days.