Check a local allergy forecast for pollen levels. Air quality and pollen measure different things.
Brownsville air quality in 2024
Days with good air
27%
99 of 366 days
Median AQI
61
Moderate
Unhealthy-for-sensitive days or worse
61
Main pollutant
PM2.5
322 days
Worst reading
AQI 171
Unhealthy
Good: 99 days
Moderate: 206 days
Unhealthy for sensitive groups: 48 days
Unhealthy: 13 days
Air quality by month
Average daily AQI for each month, 2022–2024. September is usually the cleanest month and May the worst.
52Jan52% good
55Feb39% good
65Mar14% good
71Apr20% good
85May17% good
68Jun29% good
60Jul25% good
46Aug52% good
41Sep73% good
49Oct58% good
46Nov62% good
49Dec54% good
Ten-year trend
20152 daysmedian 48
20162 daysmedian 45
20170 daysmedian 42
20180 daysmedian 51
20190 daysmedian 52
20209 daysmedian 52
20210 daysmedian 52
20223 daysmedian 48
20236 daysmedian 54
202461 daysmedian 61
Bars show days each year at “unhealthy for sensitive groups” (AQI above 100) or worse.
Worst air days, 2022–2024
171May 10, 2024 · Unhealthy · fine particles (PM2.5)
170May 17, 2024 · Unhealthy · fine particles (PM2.5)
167May 9, 2024 · Unhealthy · fine particles (PM2.5)
164May 27, 2024 · Unhealthy · fine particles (PM2.5)
162May 16, 2024 · Unhealthy · fine particles (PM2.5)
Reading the AQI
Ozone forms on hot, sunny afternoons, so it peaks in summer; plan runs and outdoor play for the morning on high-ozone days. Fine particles (PM2.5) come from wildfire smoke, traffic and wood burning and can spike in any season. Above 100, people with asthma, heart or lung conditions, older adults and children should limit long or heavy exertion outdoors.
In 2024, 27% of days had good air (AQI 50 or below) at Cameron County monitors, 56% were moderate and 61 days reached unhealthy for sensitive groups or worse. The median AQI was 61.
When is air quality worst in Brownsville?
From 2022 to 2024, May had the highest average AQI (85) and September the lowest (41).
What is the main air pollutant in Brownsville?
fine particles (PM2.5) was the main pollutant on 322 of 366 days in 2024.
Is Brownsville’s air getting better or worse?
The median AQI was 48 in 2015 and 61 in 2024; days at unhealthy for sensitive groups or worse went from 2 to 61.