EnviroNearby

Brazoria County, Texas air quality history

Daily Air Quality Index summaries from EPA monitors in Brazoria, Texas, 1980–2025.

81%
Good days in 2025
35
Median daily AQI, 2025
8
Days above 100 in 2025
365
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Brazoria, Texas on 365 days. 295 of those days (81%) were in the Good range, and the median daily AQI was 35. That median is lower than the typical monitored county in Texas (median 43.5 across 44 counties), and lower than the typical monitored U.S. county (40). The main pollutant was ozone on 326 days. Across the years with fuller monitoring, the share of Good days held roughly steady: an average of 80% in 1980–1982 versus 82% 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%1980: Good 212 of 257 days1980: Moderate 32 of 257 days1980: Unhealthy for Sensitive Groups 10 of 257 days1980: Unhealthy 2 of 257 days1980: Very Unhealthy 1 of 257 days19801981: Good 189 of 247 days1981: Moderate 36 of 247 days1981: Unhealthy for Sensitive Groups 11 of 247 days1981: Unhealthy 9 of 247 days1981: Very Unhealthy 2 of 247 days1982: Good 201 of 250 days1982: Moderate 28 of 250 days1982: Unhealthy for Sensitive Groups 16 of 250 days1982: Unhealthy 4 of 250 days1982: Very Unhealthy 1 of 250 days1983: Good 228 of 284 days1983: Moderate 31 of 284 days1983: Unhealthy for Sensitive Groups 15 of 284 days1983: Unhealthy 6 of 284 days1983: Very Unhealthy 4 of 284 days1984: Good 206 of 266 days1984: Moderate 43 of 266 days1984: Unhealthy for Sensitive Groups 14 of 266 days1984: Unhealthy 3 of 266 days1985: Good 188 of 214 days1985: Moderate 21 of 214 days1985: Unhealthy for Sensitive Groups 5 of 214 days19851986: Good 231 of 297 days1986: Moderate 49 of 297 days1986: Unhealthy for Sensitive Groups 13 of 297 days1986: Unhealthy 3 of 297 days1986: Very Unhealthy 1 of 297 days1988: Good 237 of 299 days1988: Moderate 35 of 299 days1988: Unhealthy for Sensitive Groups 19 of 299 days1988: Unhealthy 7 of 299 days1988: Very Unhealthy 1 of 299 days1990: Good 171 of 211 days1990: Moderate 27 of 211 days1990: Unhealthy for Sensitive Groups 6 of 211 days1990: Unhealthy 5 of 211 days1990: Very Unhealthy 2 of 211 days1991: Good 203 of 270 days1991: Moderate 46 of 270 days1991: Unhealthy for Sensitive Groups 13 of 270 days1991: Unhealthy 6 of 270 days1991: Very Unhealthy 2 of 270 days1992: Good 243 of 286 days1992: Moderate 23 of 286 days1992: Unhealthy for Sensitive Groups 10 of 286 days1992: Unhealthy 9 of 286 days1992: Very Unhealthy 1 of 286 days19921993: Good 264 of 340 days1993: Moderate 42 of 340 days1993: Unhealthy for Sensitive Groups 28 of 340 days1993: Unhealthy 5 of 340 days1993: Very Unhealthy 1 of 340 days1994: Good 251 of 315 days1994: Moderate 47 of 315 days1994: Unhealthy for Sensitive Groups 14 of 315 days1994: Unhealthy 2 of 315 days1994: Very Unhealthy 1 of 315 days1995: Good 214 of 294 days1995: Moderate 41 of 294 days1995: Unhealthy for Sensitive Groups 25 of 294 days1995: Unhealthy 9 of 294 days1995: Very Unhealthy 5 of 294 days1996: Good 289 of 317 days1996: Moderate 22 of 317 days1996: Unhealthy for Sensitive Groups 3 of 317 days1996: Unhealthy 3 of 317 days1997: Good 291 of 357 days1997: Moderate 40 of 357 days1997: Unhealthy for Sensitive Groups 24 of 357 days1997: Unhealthy 2 of 357 days19971998: Good 294 of 358 days1998: Moderate 43 of 358 days1998: Unhealthy for Sensitive Groups 17 of 358 days1998: Unhealthy 3 of 358 days1998: Very Unhealthy 1 of 358 days1999: Good 288 of 354 days1999: Moderate 39 of 354 days1999: Unhealthy for Sensitive Groups 18 of 354 days1999: Unhealthy 5 of 354 days1999: Very Unhealthy 4 of 354 days2000: Good 295 of 364 days2000: Moderate 60 of 364 days2000: Unhealthy for Sensitive Groups 7 of 364 days2000: Unhealthy 1 of 364 days2000: Very Unhealthy 1 of 364 days2001: Good 248 of 363 days2001: Moderate 81 of 363 days2001: Unhealthy for Sensitive Groups 26 of 363 days2001: Unhealthy 8 of 363 days2002: Good 265 of 365 days2002: Moderate 77 of 365 days2002: Unhealthy for Sensitive Groups 14 of 365 days2002: Unhealthy 6 of 365 days2002: Very Unhealthy 3 of 365 days20022003: Good 274 of 365 days2003: Moderate 56 of 365 days2003: Unhealthy for Sensitive Groups 24 of 365 days2003: Unhealthy 10 of 365 days2003: Very Unhealthy 1 of 365 days2004: Good 271 of 364 days2004: Moderate 50 of 364 days2004: Unhealthy for Sensitive Groups 27 of 364 days2004: Unhealthy 13 of 364 days2004: Very Unhealthy 3 of 364 days2005: Good 249 of 360 days2005: Moderate 72 of 360 days2005: Unhealthy for Sensitive Groups 27 of 360 days2005: Unhealthy 12 of 360 days2006: Good 289 of 365 days2006: Moderate 39 of 365 days2006: Unhealthy for Sensitive Groups 22 of 365 days2006: Unhealthy 13 of 365 days2006: Very Unhealthy 2 of 365 days2007: Good 301 of 365 days2007: Moderate 49 of 365 days2007: Unhealthy for Sensitive Groups 11 of 365 days2007: Unhealthy 4 of 365 days20072008: Good 297 of 360 days2008: Moderate 51 of 360 days2008: Unhealthy for Sensitive Groups 10 of 360 days2008: Unhealthy 2 of 360 days2009: Good 308 of 365 days2009: Moderate 46 of 365 days2009: Unhealthy for Sensitive Groups 6 of 365 days2009: Unhealthy 5 of 365 days2010: Good 304 of 365 days2010: Moderate 40 of 365 days2010: Unhealthy for Sensitive Groups 15 of 365 days2010: Unhealthy 6 of 365 days2011: Good 289 of 365 days2011: Moderate 45 of 365 days2011: Unhealthy for Sensitive Groups 23 of 365 days2011: Unhealthy 7 of 365 days2011: Very Unhealthy 1 of 365 days2012: Good 283 of 366 days2012: Moderate 62 of 366 days2012: Unhealthy for Sensitive Groups 16 of 366 days2012: Unhealthy 4 of 366 days2012: Very Unhealthy 1 of 366 days20122013: Good 316 of 365 days2013: Moderate 41 of 365 days2013: Unhealthy for Sensitive Groups 5 of 365 days2013: Unhealthy 3 of 365 days2014: Good 330 of 365 days2014: Moderate 31 of 365 days2014: Unhealthy for Sensitive Groups 3 of 365 days2014: Unhealthy 1 of 365 days2015: Good 308 of 365 days2015: Moderate 42 of 365 days2015: Unhealthy for Sensitive Groups 11 of 365 days2015: Unhealthy 4 of 365 days2016: Good 313 of 366 days2016: Moderate 50 of 366 days2016: Unhealthy for Sensitive Groups 3 of 366 days2017: Good 306 of 357 days2017: Moderate 44 of 357 days2017: Unhealthy for Sensitive Groups 6 of 357 days2017: Unhealthy 1 of 357 days20172018: Good 329 of 365 days2018: Moderate 31 of 365 days2018: Unhealthy for Sensitive Groups 4 of 365 days2018: Unhealthy 1 of 365 days2019: Good 325 of 365 days2019: Moderate 33 of 365 days2019: Unhealthy for Sensitive Groups 6 of 365 days2019: Unhealthy 1 of 365 days2020: Good 328 of 365 days2020: Moderate 34 of 365 days2020: Unhealthy for Sensitive Groups 2 of 365 days2020: Unhealthy 1 of 365 days2021: Good 331 of 365 days2021: Moderate 22 of 365 days2021: Unhealthy for Sensitive Groups 11 of 365 days2021: Unhealthy 1 of 365 days2022: Good 311 of 365 days2022: Moderate 46 of 365 days2022: Unhealthy for Sensitive Groups 8 of 365 days20222023: Good 301 of 365 days2023: Moderate 47 of 365 days2023: Unhealthy for Sensitive Groups 16 of 365 days2023: Unhealthy 1 of 365 days2024: Good 303 of 365 days2024: Moderate 56 of 365 days2024: Unhealthy for Sensitive Groups 5 of 365 days2024: Unhealthy 1 of 365 days2025: Good 295 of 365 days2025: Moderate 62 of 365 days2025: Unhealthy for Sensitive Groups 8 of 365 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 year0501001501980: 90th percentile AQI 741981: 90th percentile AQI 901982: 90th percentile AQI 871983: 90th percentile AQI 901984: 90th percentile AQI 901985: 90th percentile AQI 571986: 90th percentile AQI 771988: 90th percentile AQI 1001990: 90th percentile AQI 741991: 90th percentile AQI 931992: 90th percentile AQI 771993: 90th percentile AQI 1011994: 90th percentile AQI 801995: 90th percentile AQI 1081996: 90th percentile AQI 491997: 90th percentile AQI 841998: 90th percentile AQI 801999: 90th percentile AQI 802000: 90th percentile AQI 622001: 90th percentile AQI 972002: 90th percentile AQI 842003: 90th percentile AQI 1002004: 90th percentile AQI 1122005: 90th percentile AQI 1052006: 90th percentile AQI 1012007: 90th percentile AQI 772008: 90th percentile AQI 672009: 90th percentile AQI 642010: 90th percentile AQI 772011: 90th percentile AQI 902012: 90th percentile AQI 842013: 90th percentile AQI 582014: 90th percentile AQI 502015: 90th percentile AQI 712016: 90th percentile AQI 612017: 90th percentile AQI 642018: 90th percentile AQI 502019: 90th percentile AQI 512020: 90th percentile AQI 512021: 90th percentile AQI 502022: 90th percentile AQI 612023: 90th percentile AQI 672024: 90th percentile AQI 602025: 90th percentile AQI 711980: Median AQI 351981: Median AQI 381982: Median AQI 311983: Median AQI 331984: Median AQI 331985: Median AQI 281986: Median AQI 321988: Median AQI 311990: Median AQI 301991: Median AQI 371992: Median AQI 321993: Median AQI 361994: Median AQI 351995: Median AQI 331996: Median AQI 301997: Median AQI 321998: Median AQI 311999: Median AQI 312000: Median AQI 312001: Median AQI 382002: Median AQI 402003: Median AQI 382004: Median AQI 342005: Median AQI 382006: Median AQI 372007: Median AQI 342008: Median AQI 352009: Median AQI 352010: Median AQI 362011: Median AQI 362012: Median AQI 342013: Median AQI 342014: Median AQI 322015: Median AQI 332016: Median AQI 362017: Median AQI 372018: Median AQI 312019: Median AQI 332020: Median AQI 332021: Median AQI 342022: Median AQI 352023: Median AQI 362024: Median AQI 372025: Median AQI 351980198519921997200220072012201720222025
  • 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
Ozone32689%
Fine particles (PM2.5)288%
Nitrogen dioxide (NO₂)113%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
20253652956280003571143Ozone
20243653035651003760164Ozone
202336530147161003667156Ozone
20223653114680003561119Ozone
202136533122111003450159Ozone
20203653283421003351182Ozone
20193653253361003351161Ozone
20183653293141003150166Ozone
20173573064461003764154Ozone
20163663135030003661115Ozone
201536530842114003371164Ozone
20143653303131003250174Ozone
20133653164153003458172Ozone
201236628362164103484233Ozone
201136528945237103690203Ozone
201036530440156003677172Ozone
20093653084665003564177Ozone
200836029751102003567151Ozone
200736530149114003477187Ozone
20063652893922132037101217Ozone
20053602497227120038105187Ozone
20043642715027133034112212Ozone
20033652745624101038100206Ozone
200236526577146304084217Ozone
200136324881268003897172Ozone
20003642956071103162216Ozone
199935428839185403180220Ozone
199835829443173103180242Ozone
199735729140242003284177Ozone
19963172892233003049177Ozone
1995294214412595033108239Ozone
199431525147142103580205Ozone
1993340264422851036101212Ozone
199228624323109103277201Ozone
199127020346136203793221Ozone
19902111712765203074228Ozone
1988299237351971031100213Ozone
198629723149133103277222Ozone
19852141882150002857119Ozone
198426620643143003390177Ozone
198328422831156403390216Ozone
198225020128164103187202Ozone
198124718936119203890238Ozone
198025721232102103574203Ozone

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 1980–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem