EnviroNearby

Brazos County, Texas air quality history

Daily Air Quality Index summaries from EPA monitors in Brazos, Texas, 2020–2025.

69%
Good days in 2025
40
Median daily AQI, 2025
0
Days above 100 in 2025
340
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Brazos, Texas on 340 days. 233 of those days (69%) were in the Good range, and the median daily AQI was 40. That median is lower than the typical monitored county in Texas (median 43.5 across 44 counties), and about the same as the typical monitored U.S. county (40). The main pollutant was fine particles (PM2.5) on 340 days. Across the years with fuller monitoring, the share of Good days fell: an average of 71% in 2020–2022 versus 67% in 2023–2025.

How the days broke down each year

Each bar is one year. The colored segments show the share of monitored days that fell in each AQI category.

Share of monitored days in each AQI category, by year0%25%50%75%100%2020: Good 210 of 303 days2020: Moderate 93 of 303 days20202021: Good 248 of 356 days2021: Moderate 108 of 356 days20212022: Good 251 of 345 days2022: Moderate 94 of 345 days20222023: Good 233 of 348 days2023: Moderate 115 of 348 days20232024: Good 232 of 353 days2024: Moderate 120 of 353 days2024: Unhealthy for Sensitive Groups 1 of 353 days20242025: Good 233 of 340 days2025: Moderate 107 of 340 days2025
  • Good
  • Moderate
  • Unhealthy for Sensitive Groups
  • Unhealthy
  • Very Unhealthy
  • Hazardous

Typical and high-end AQI over time

The median is the middle day of the year. The 90th percentile is the level that only the highest 10% of days exceeded.

Median and 90th-percentile daily AQI, by year0501002020: 90th percentile AQI 572021: 90th percentile AQI 582022: 90th percentile AQI 552023: 90th percentile AQI 602024: 90th percentile AQI 582025: 90th percentile AQI 572020: Median AQI 402021: Median AQI 402022: Median AQI 402023: Median AQI 392024: Median AQI 392025: Median AQI 40202020212022202320242025
  • Median daily AQI
  • 90th-percentile daily AQI

Main pollutant by day, 2025

On each monitored day, the AQI reflects whichever measured pollutant had the highest index. This counts how many days each pollutant set the AQI. A pollutant that was not measured here cannot appear.

PollutantDays as main pollutantShare of monitored days
Fine particles (PM2.5)340100%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
20253402331070000405778PM2.5
202435323212010003958102PM2.5
20233482331150000396079PM2.5
2022345251940000405594PM2.5
20213562481080000405885PM2.5
2020303210930000405799PM2.5

What this data can and can’t tell you

It is a county-level summary. EPA reports one AQI per day for the county, based on the monitors operating there. Air at a particular street, school or home can differ, especially near roads, industry or wildfire smoke.

It is not a health assessment. The AQI is EPA’s scale for communicating daily air quality. A county’s history can’t tell you what the health risk is for any particular person. For daily conditions and health guidance, see AirNow.

Rules change over time. EPA has revised AQI breakpoints, most recently for fine particles in 2024, so some year-to-year change can reflect the scale rather than the air.

Counties in Texas with a similar median AQI in 2025

All monitored counties in Texas

Source: U.S. EPA AirData, “Annual AQI by County” files for 2020–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem