EnviroNearby

San Juan County, New Mexico air quality history

Daily Air Quality Index summaries from EPA monitors in San Juan, New Mexico, 1980–2025.

68%
Good days in 2025
47
Median daily AQI, 2025
0
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 San Juan, New Mexico on 365 days. 248 of those days (68%) were in the Good range, and the median daily AQI was 47. That median is higher than the typical monitored county in New Mexico (median 44 across 13 counties), and higher than the typical monitored U.S. county (40). The main pollutant was ozone on 361 days. Across the years with fuller monitoring, the share of Good days fell: an average of 96% in 1980–1982 versus 65% in 2023–2025.

Years with fewer than 120 monitored days (1987) 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%1980: Good 341 of 362 days1980: Moderate 21 of 362 days19801981: Good 346 of 365 days1981: Moderate 19 of 365 days1982: Good 359 of 365 days1982: Moderate 6 of 365 days1983: Good 356 of 363 days1983: Moderate 7 of 363 days1984: Good 355 of 366 days1984: Moderate 10 of 366 days1984: Unhealthy for Sensitive Groups 1 of 366 days1985: Good 215 of 228 days1985: Moderate 13 of 228 days19851987: Good 92 of 92 days1988: Good 355 of 366 days1988: Moderate 11 of 366 days1989: Good 356 of 365 days1989: Moderate 9 of 365 days1990: Good 357 of 365 days1990: Moderate 8 of 365 days1991: Good 356 of 364 days1991: Moderate 8 of 364 days19911992: Good 362 of 366 days1992: Moderate 4 of 366 days1993: Good 361 of 365 days1993: Moderate 4 of 365 days1994: Good 358 of 358 days1995: Good 365 of 365 days1996: Good 366 of 366 days19961997: Good 321 of 365 days1997: Moderate 44 of 365 days1998: Good 253 of 365 days1998: Moderate 108 of 365 days1998: Unhealthy for Sensitive Groups 4 of 365 days1999: Good 271 of 365 days1999: Moderate 92 of 365 days1999: Unhealthy for Sensitive Groups 2 of 365 days2000: Good 213 of 366 days2000: Moderate 125 of 366 days2000: Unhealthy for Sensitive Groups 28 of 366 days2001: Good 184 of 365 days2001: Moderate 163 of 365 days2001: Unhealthy for Sensitive Groups 18 of 365 days20012002: Good 211 of 365 days2002: Moderate 135 of 365 days2002: Unhealthy for Sensitive Groups 19 of 365 days2003: Good 201 of 365 days2003: Moderate 148 of 365 days2003: Unhealthy for Sensitive Groups 16 of 365 days2004: Good 252 of 365 days2004: Moderate 111 of 365 days2004: Unhealthy for Sensitive Groups 2 of 365 days2005: Good 255 of 365 days2005: Moderate 102 of 365 days2005: Unhealthy for Sensitive Groups 8 of 365 days2006: Good 191 of 365 days2006: Moderate 153 of 365 days2006: Unhealthy for Sensitive Groups 20 of 365 days2006: Unhealthy 1 of 365 days20062007: Good 156 of 365 days2007: Moderate 167 of 365 days2007: Unhealthy for Sensitive Groups 42 of 365 days2008: Good 206 of 366 days2008: Moderate 157 of 366 days2008: Unhealthy for Sensitive Groups 3 of 366 days2009: Good 308 of 365 days2009: Moderate 57 of 365 days2010: Good 240 of 365 days2010: Moderate 115 of 365 days2010: Unhealthy for Sensitive Groups 6 of 365 days2010: Unhealthy 2 of 365 days2010: Very Unhealthy 2 of 365 days2011: Good 227 of 365 days2011: Moderate 125 of 365 days2011: Unhealthy for Sensitive Groups 13 of 365 days20112012: Good 205 of 366 days2012: Moderate 149 of 366 days2012: Unhealthy for Sensitive Groups 12 of 366 days2013: Good 236 of 365 days2013: Moderate 123 of 365 days2013: Unhealthy for Sensitive Groups 5 of 365 days2013: Unhealthy 1 of 365 days2014: Good 272 of 365 days2014: Moderate 93 of 365 days2015: Good 263 of 365 days2015: Moderate 100 of 365 days2015: Unhealthy for Sensitive Groups 2 of 365 days2016: Good 273 of 366 days2016: Moderate 91 of 366 days2016: Unhealthy for Sensitive Groups 2 of 366 days20162017: Good 230 of 365 days2017: Moderate 129 of 365 days2017: Unhealthy for Sensitive Groups 6 of 365 days2018: Good 213 of 365 days2018: Moderate 136 of 365 days2018: Unhealthy for Sensitive Groups 16 of 365 days2019: Good 208 of 365 days2019: Moderate 157 of 365 days2020: Good 265 of 366 days2020: Moderate 96 of 366 days2020: Unhealthy for Sensitive Groups 5 of 366 days2021: Good 237 of 365 days2021: Moderate 120 of 365 days2021: Unhealthy for Sensitive Groups 8 of 365 days20212022: Good 238 of 365 days2022: Moderate 116 of 365 days2022: Unhealthy for Sensitive Groups 9 of 365 days2022: Unhealthy 1 of 365 days2022: Very Unhealthy 1 of 365 days2023: Good 249 of 365 days2023: Moderate 112 of 365 days2023: Unhealthy for Sensitive Groups 4 of 365 days2024: Good 218 of 366 days2024: Moderate 137 of 366 days2024: Unhealthy for Sensitive Groups 11 of 366 days2025: Good 248 of 365 days2025: Moderate 117 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 441981: 90th percentile AQI 471982: 90th percentile AQI 341983: 90th percentile AQI 391984: 90th percentile AQI 451985: 90th percentile AQI 471987: 90th percentile AQI 301988: 90th percentile AQI 381989: 90th percentile AQI 381990: 90th percentile AQI 411991: 90th percentile AQI 381992: 90th percentile AQI 391993: 90th percentile AQI 321994: 90th percentile AQI 251995: 90th percentile AQI 221996: 90th percentile AQI 221997: 90th percentile AQI 541998: 90th percentile AQI 741999: 90th percentile AQI 642000: 90th percentile AQI 932001: 90th percentile AQI 932002: 90th percentile AQI 932003: 90th percentile AQI 902004: 90th percentile AQI 712005: 90th percentile AQI 712006: 90th percentile AQI 902007: 90th percentile AQI 1012008: 90th percentile AQI 802009: 90th percentile AQI 542010: 90th percentile AQI 782011: 90th percentile AQI 802012: 90th percentile AQI 872013: 90th percentile AQI 772014: 90th percentile AQI 612015: 90th percentile AQI 672016: 90th percentile AQI 712017: 90th percentile AQI 802018: 90th percentile AQI 932019: 90th percentile AQI 902020: 90th percentile AQI 642021: 90th percentile AQI 772022: 90th percentile AQI 772023: 90th percentile AQI 742024: 90th percentile AQI 872025: 90th percentile AQI 741980: Median AQI 221981: Median AQI 201982: Median AQI 181983: Median AQI 201984: Median AQI 241985: Median AQI 201987: Median AQI 201988: Median AQI 161989: Median AQI 221990: Median AQI 231991: Median AQI 191992: Median AQI 181993: Median AQI 171994: Median AQI 111995: Median AQI 101996: Median AQI 111997: Median AQI 351998: Median AQI 441999: Median AQI 442000: Median AQI 482001: Median AQI 502002: Median AQI 482003: Median AQI 492004: Median AQI 452005: Median AQI 442006: Median AQI 492007: Median AQI 542008: Median AQI 492009: Median AQI 432010: Median AQI 452011: Median AQI 472012: Median AQI 482013: Median AQI 462014: Median AQI 442015: Median AQI 442016: Median AQI 442017: Median AQI 472018: Median AQI 472019: Median AQI 492020: Median AQI 452021: Median AQI 462022: Median AQI 452023: Median AQI 462024: Median AQI 482025: Median AQI 471980198519911996200120062011201620212025
  • 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
Ozone36199%
Coarse particles (PM10)31%
Nitrogen dioxide (NO₂)1<1%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
20253652481170000477497Ozone
2024366218137110004887115Ozone
202336524911240004674117Ozone
202236523811691104577220Ozone
202136523712080004677126Ozone
20203662659650004564109Ozone
20193652081570000499097Ozone
2018365213136160004793129Ozone
201736523012960004780133Ozone
20163662739120004471108Ozone
201536526310020004467115Ozone
2014365272930000446197Ozone
201336523612351004677158Ozone
2012366205149120004887112Ozone
2011365227125130004780143Ozone
201036524011562204578251Ozone
20093653085700004354100Ozone
200836620615730004980122Ozone
20073651561674200054101133Ozone
2006365191153201004990154Ozone
200536525510280004471136Ozone
200436525211120004571108Ozone
2003365201148160004990126Ozone
2002365211135190004893133Ozone
2001365184163180005093122Ozone
2000366213125280004893150Ozone
19993652719220004464112Ozone
199836525310840004474108Ozone
1997365321440000355497Ozone
199636636600000112234CO
199536536500000102232CO
199435835800000112546CO
199336536140000173265CO
199236636240000183968NO2
199136435680000193869NO2
199036535780000234161NO2
198936535690000223868CO
1988366355110000163868CO
1987929200000203047CO
1985228215130000204768NO2
19843663551010002445108CO
198336335670000203954CO
198236535960000183475CO
1981365346190000204772CO
1980362341210000224464CO

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 New Mexico with a similar median AQI in 2025

All monitored counties in New Mexico

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