EnviroNearby

Hidalgo County, Texas air quality history

Daily Air Quality Index summaries from EPA monitors in Hidalgo, Texas, 1996–2025.

44%
Good days in 2025
52
Median daily AQI, 2025
4
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 Hidalgo, Texas on 365 days. 162 of those days (44%) were in the Good range, and the median daily AQI was 52. That median is higher than the typical monitored county in Texas (median 43.5 across 44 counties), and higher than the typical monitored U.S. county (40). The main pollutant was fine particles (PM2.5) on 280 days. Across the years with fuller monitoring, the share of Good days fell: an average of 90% in 1997–1999 versus 48% in 2023–2025.

Years with fewer than 120 monitored days (1996) are shown in the table but left out of comparisons and trend statements.

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%1996: Good 99 of 103 days1996: Moderate 4 of 103 days19961997: Good 335 of 357 days1997: Moderate 20 of 357 days1997: Unhealthy for Sensitive Groups 2 of 357 days1998: Good 319 of 357 days1998: Moderate 33 of 357 days1998: Unhealthy for Sensitive Groups 5 of 357 days1999: Good 315 of 365 days1999: Moderate 43 of 365 days1999: Unhealthy for Sensitive Groups 7 of 365 days2000: Good 283 of 366 days2000: Moderate 76 of 366 days2000: Unhealthy for Sensitive Groups 7 of 366 days2001: Good 247 of 365 days2001: Moderate 110 of 365 days2001: Unhealthy for Sensitive Groups 8 of 365 days20012002: Good 254 of 365 days2002: Moderate 106 of 365 days2002: Unhealthy for Sensitive Groups 4 of 365 days2002: Unhealthy 1 of 365 days2003: Good 237 of 365 days2003: Moderate 119 of 365 days2003: Unhealthy for Sensitive Groups 9 of 365 days2004: Good 273 of 366 days2004: Moderate 91 of 366 days2004: Unhealthy for Sensitive Groups 1 of 366 days2004: Unhealthy 1 of 366 days2005: Good 135 of 365 days2005: Moderate 223 of 365 days2005: Unhealthy for Sensitive Groups 7 of 365 days2006: Good 120 of 365 days2006: Moderate 245 of 365 days20062007: Good 145 of 365 days2007: Moderate 219 of 365 days2007: Unhealthy for Sensitive Groups 1 of 365 days2008: Good 133 of 362 days2008: Moderate 227 of 362 days2008: Unhealthy for Sensitive Groups 2 of 362 days2009: Good 151 of 365 days2009: Moderate 214 of 365 days2010: Good 186 of 362 days2010: Moderate 176 of 362 days2011: Good 173 of 365 days2011: Moderate 191 of 365 days2011: Unhealthy for Sensitive Groups 1 of 365 days20112012: Good 169 of 366 days2012: Moderate 197 of 366 days2013: Good 224 of 365 days2013: Moderate 140 of 365 days2013: Unhealthy for Sensitive Groups 1 of 365 days2014: Good 203 of 365 days2014: Moderate 162 of 365 days2015: Good 189 of 365 days2015: Moderate 175 of 365 days2015: Unhealthy for Sensitive Groups 1 of 365 days2016: Good 232 of 366 days2016: Moderate 133 of 366 days2016: Unhealthy for Sensitive Groups 1 of 366 days20162017: Good 218 of 365 days2017: Moderate 147 of 365 days2018: Good 173 of 363 days2018: Moderate 186 of 363 days2018: Unhealthy for Sensitive Groups 4 of 363 days2019: Good 184 of 365 days2019: Moderate 179 of 365 days2019: Unhealthy for Sensitive Groups 2 of 365 days2020: Good 222 of 366 days2020: Moderate 139 of 366 days2020: Unhealthy for Sensitive Groups 3 of 366 days2020: Unhealthy 2 of 366 days2021: Good 169 of 363 days2021: Moderate 192 of 363 days2021: Unhealthy for Sensitive Groups 2 of 363 days20212022: Good 197 of 365 days2022: Moderate 165 of 365 days2022: Unhealthy for Sensitive Groups 3 of 365 days2023: Good 206 of 357 days2023: Moderate 151 of 357 days2024: Good 150 of 366 days2024: Moderate 192 of 366 days2024: Unhealthy for Sensitive Groups 19 of 366 days2024: Unhealthy 5 of 366 days2025: Good 162 of 365 days2025: Moderate 199 of 365 days2025: Unhealthy for Sensitive Groups 4 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 year0501001996: 90th percentile AQI 431997: 90th percentile AQI 471998: 90th percentile AQI 511999: 90th percentile AQI 612000: 90th percentile AQI 622001: 90th percentile AQI 672002: 90th percentile AQI 662003: 90th percentile AQI 712004: 90th percentile AQI 602005: 90th percentile AQI 772006: 90th percentile AQI 742007: 90th percentile AQI 692008: 90th percentile AQI 712009: 90th percentile AQI 702010: 90th percentile AQI 692011: 90th percentile AQI 692012: 90th percentile AQI 672013: 90th percentile AQI 692014: 90th percentile AQI 672015: 90th percentile AQI 682016: 90th percentile AQI 652017: 90th percentile AQI 652018: 90th percentile AQI 712019: 90th percentile AQI 692020: 90th percentile AQI 692021: 90th percentile AQI 742022: 90th percentile AQI 702023: 90th percentile AQI 682024: 90th percentile AQI 872025: 90th percentile AQI 691996: Median AQI 281997: Median AQI 311998: Median AQI 321999: Median AQI 322000: Median AQI 362001: Median AQI 422002: Median AQI 422003: Median AQI 412004: Median AQI 382005: Median AQI 542006: Median AQI 552007: Median AQI 532008: Median AQI 542009: Median AQI 522010: Median AQI 502011: Median AQI 522012: Median AQI 512013: Median AQI 452014: Median AQI 472015: Median AQI 492016: Median AQI 432017: Median AQI 472018: Median AQI 512019: Median AQI 502020: Median AQI 442021: Median AQI 522022: Median AQI 492023: Median AQI 442024: Median AQI 542025: Median AQI 521996200120062011201620212025
  • 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)28077%
Ozone7521%
Coarse particles (PM10)103%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
202536516219940005269140PM2.5
2024366150192195005487157PM2.5
20233572061510000446895PM2.5
202236519716530004970136PM2.5
202136316919220005274108PM2.5
202036622213932004469157PM2.5
201936518417920005069106PM2.5
201836317318640005171115PM2.5
20173652181470000476596PM2.5
201636623213310004365114PM2.5
201536518917510004968107PM2.5
20143652031620000476789PM2.5
201336522414010004569106PM2.5
20123661691970000516784PM2.5
201136517319110005269101PM2.5
20103621861760000506991PM2.5
20093651512140000527087PM2.5
200836213322720005471119PM2.5
200736514521910005369101PM2.5
20063651202450000557497PM2.5
200536513522370005477122PM2.5
20043662739111003860156Ozone
200336523711990004171150Ozone
200236525410641004266159Ozone
200136524711080004267150Ozone
20003662837670003662136Ozone
19993653154370003261129Ozone
19983573193350003251136Ozone
19973573352020003147122Ozone
19961039940000284383Ozone

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 1996–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem