Air quality in Cameron County, TX

Includes Brownsville and Harlingen · EPA monitor readings, 2021 to 2025 · 421,000 people

Frequent bad daysMostly fine particles
Bad-air days a year
16
days with an AQI over 100

About 1 day in 23. That's up from about 3 a year in the early 2000s. Cameron County has the 6th most bad-air days of the 44 Texas counties with monitors.

3days unhealthy for everyoneAQI over 150, a year
54AQI on a typical dayModerate: fine for most people
Apr to Junworst monthsFine particles, spread through the year
184worst day since 2016Jun 26, 2020, fine particles
How to read the AQIThe EPA's air score runs from 0 to 500. Higher is worse. Over 100 counts as a bad-air day.
Typical day 54 (Moderate)Worst day 184 (Unhealthy)
Good0 to 50Moderate51 to 100Sensitive groups101 to 150Unhealthy151 to 200Very unhealthy201 to 300Hazardous301 to 500

When bad air happens in Cameron County

Average bad-air days in each month, from 10 years of daily readings since 2016. Most fall in April, May and June.

Jan0.2
Feb0.4
Mar0.9
Apr1.9
May3.0
Jun1.5
Jul0.2
Aug0.1
Sep0.3
Oct0.2
Nov0.1
Dec0.1
0123JanFebMarAprMayJunJulAugSepOctNovDecPARTICLES0123JFMAMJJASONDPARTICLES
Fine particles (smoke, soot)Ozone (smog)Bars stack in that order, from the bottom.
See the numbers by month
Average bad-air days a year in each month in Cameron County, from 10 years of daily readings
MonthOzoneFine particlesAll
January00.20.2
February00.40.4
March00.90.9
April01.91.9
May03.03.0
June01.51.5
July00.20.2
August0.100.1
September00.30.3
October00.20.2
November00.10.1
December00.10.1

The worst day since 2016 was June 26, 2020: AQI 184, from fine particles.

What causes it

The pollutant that pushed the AQI over 100 on each of the 89 bad-air days since 2016.

99%particles
1%Ozone: smog that forms in sunlight on hot days
99%Fine particles: smoke and soot

Most bad days here are fine-particle days, spread through the year, with the most in April, May and June.

CDC estimates by month, 2001 to 2022

The CDC's model counts bad-air days at the county's worst spot, from monitors and satellites. Particles (brown) fill the inside of the ring and ozone (blue) the outside.

JFMApril: 0.1 smoky days a yearAMay: 0.2 smoky days a yearMay: 0.1 ozone days a yearMJune: 0.3 smoky days a yearJJAugust: 0.0 ozone days a yearASeptember: 0.0 smoky days a yearSeptember: 0.3 ozone days a yearSOctober: 0.2 ozone days a yearONovember: 0.0 ozone days a yearNDbad daysby month
See the numbers by month
CDC estimated bad-air days a year in each month in Cameron County, 2001 to 2022
MonthFine particlesOzone
January00
February00
March00
April0.10
May0.20.1
June0.30
July00
August00
September00.3
October00.2
November00
December00

What helps in Cameron County

Most bad days here are smoke and other fine particles. Filtering the air at home helps most.

Keep one room clean on smoky days

Shut the windows and run an air purifier sized for the room.

Choosing a purifier →

Upgrade the furnace filter

Use MERV 13 if your system can take it, and run the fan on smoky days.

Furnace filters →

Wear an N95 outside on smoky days

A well-fitted N95 helps. Cloth and surgical masks do little against smoke.

Wildfire smoke guide →

For today's reading and tomorrow's forecast, check AirNow by ZIP code. Its fire and smoke map adds smoke plumes.

Parents: what schools do at each AQI level, and how to plan for smoke and ozone days.

Purifiers with a verified smoke rating

For a clean room on smoky days. Each has a smoke CADR tested by AHAM's independent program and is certified by California as a mechanical cleaner, so it makes no ozone.

Bedroom or small room

Levoit Vital 100S-P

143 smoke CADR

Everyday
up to 222 sq ft
Heavy smoke
up to 143 sq ft
Filters
about $40 a year

The cheapest unit we found with a verified smoke rating. Enough for a bedroom clean room.

$119.99 at Levoit
Best value for smoke

Levoit Vital 200S-P

250 smoke CADR

Everyday
up to 388 sq ft
Heavy smoke
up to 250 sq ft
Filters
about $50 a year

The most verified smoke cleaning per dollar of any qualifying model: 75% more than the 100S-P for $50 more.

$169.99 at Levoit
Living room or open floor

Levoit Core 600S-P

391 smoke CADR

Everyday
up to 606 sq ft
Heavy smoke
up to 391 sq ft
Filters
$60 to $120 a year

For a big room or a small apartment. Buy the LAP-C601S-WUS version, which CARB lists as mechanical.

$299.99 at Levoit

Why all 3 are Levoit: of the models we checked that pass both tests, these give the most verified smoke cleaning per dollar at each room size. Medify's MA-25 and MA-40 also pass but cost more for the same cleaning.

Ratings from the AHAM Verifide directory and CARB's certified list. Prices from Levoit's site, checked November 7, 2026; they change. We don't earn anything from these links. How to pick a purifier

Every year since 2000

Bad-air days each year. The striped part is days unhealthy for everyone, over AQI 150. The worst recent year was 2024, with 61 bad-air days.

0204060802000200520102015202061202580204060802000201020206120258
Unhealthy for sensitive groups (101 to 150)Unhealthy or worse (over 150)
See the numbers by year
Bad-air days each year in Cameron County
YearBad-air daysOver 150
200010
200110
200230
200350
200431
200540
200610
200710
200830
200900
201020
201110
201200
201300
201400
201520
201620
201700
201800
201900
202093
202100
202230
202360
20246113
202580

Cameron County and its neighbors

Bad-air days a year, 2021 to 2025. Texas counties with monitors averaged about 18 bad-air days a year, weighted by population.

Cameron County16
Hidalgo County7

Nearest counties with a full report: Nueces County, TX (6 bad-air days a year), Webb County, TX (5 bad-air days a year).

Questions people ask about air in Cameron County

How often is the air bad in Cameron County?

From 2021 to 2025, monitors in Cameron County recorded about 16 bad-air days a year with an AQI above 100, which is unhealthy for sensitive groups or worse. The worst year in that stretch was 2024, with 61 bad-air days.

What causes bad air in Cameron County?

Most bad days here are fine-particle days, spread through the year, with the most in April, May and June.

Where can I see today's air quality in Cameron County?

AirNow, run by the EPA and its partners, shows the current AQI and tomorrow's forecast for your ZIP code. Its fire and smoke map adds smoke plumes. On a typical day the AQI in Cameron County is about 54, which is moderate, fine for most people. Check it most in April, May and June, when bad days here cluster.

About these numbers

Day counts come from the EPA's county air quality summaries, which take the worst reading across a county's monitors each day. Monitors here reported on about 365 days a year from 2021 to 2025. A county is large, and your street can be cleaner or worse. CDC's model, which estimates every county from monitors and satellites, gives the worst spot in Cameron County about 2 high-particle days and almost no high-ozone days a year from 2018 to 2022. That's well below what the monitors here recorded. The monitors are a direct measurement, so they're the number to trust.

Sources: EPA AirData county AQI summaries (2000 to 2025) and daily county AQI (2016 to 2025); CDC Environmental Public Health Tracking Network modeled PM2.5 and ozone (2001 to 2022). Updated November 8, 2026.