EnviroNearby

St. James Parish, Louisiana air quality history

Daily Air Quality Index summaries from EPA monitors in St. James, Louisiana, 1983–2025.

94%
Good days in 2025
33
Median daily AQI, 2025
0
Days above 100 in 2025
359
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for St. James, Louisiana on 359 days. 337 of those days (94%) were in the Good range, and the median daily AQI was 33. That median is lower than the typical monitored county in Louisiana (median 42 across 21 counties), and lower than the typical monitored U.S. county (40). The main pollutant was ozone on 359 days. Across the years with fuller monitoring, the share of Good days rose: an average of 84% in 1983–1990 versus 92% in 2023–2025.

Years with fewer than 120 monitored days (1984, 1988) 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%1983: Good 118 of 134 days1983: Moderate 12 of 134 days1983: Unhealthy for Sensitive Groups 4 of 134 days19831984: Good 88 of 94 days1984: Moderate 4 of 94 days1984: Unhealthy for Sensitive Groups 1 of 94 days1984: Unhealthy 1 of 94 days1988: Good 75 of 80 days1988: Moderate 5 of 80 days1989: Good 286 of 354 days1989: Moderate 51 of 354 days1989: Unhealthy for Sensitive Groups 14 of 354 days1989: Unhealthy 3 of 354 days1990: Good 299 of 363 days1990: Moderate 43 of 363 days1990: Unhealthy for Sensitive Groups 19 of 363 days1990: Unhealthy 2 of 363 days1991: Good 315 of 349 days1991: Moderate 27 of 349 days1991: Unhealthy for Sensitive Groups 7 of 349 days19911992: Good 345 of 359 days1992: Moderate 10 of 359 days1992: Unhealthy for Sensitive Groups 3 of 359 days1992: Unhealthy 1 of 359 days1993: Good 333 of 365 days1993: Moderate 28 of 365 days1993: Unhealthy for Sensitive Groups 4 of 365 days1994: Good 298 of 364 days1994: Moderate 46 of 364 days1994: Unhealthy for Sensitive Groups 18 of 364 days1994: Unhealthy 2 of 364 days1995: Good 279 of 364 days1995: Moderate 47 of 364 days1995: Unhealthy for Sensitive Groups 30 of 364 days1995: Unhealthy 8 of 364 days1996: Good 316 of 362 days1996: Moderate 38 of 362 days1996: Unhealthy for Sensitive Groups 6 of 362 days1996: Unhealthy 2 of 362 days19961997: Good 295 of 362 days1997: Moderate 52 of 362 days1997: Unhealthy for Sensitive Groups 14 of 362 days1997: Unhealthy 1 of 362 days1998: Good 305 of 362 days1998: Moderate 40 of 362 days1998: Unhealthy for Sensitive Groups 14 of 362 days1998: Unhealthy 3 of 362 days1999: Good 282 of 363 days1999: Moderate 52 of 363 days1999: Unhealthy for Sensitive Groups 24 of 363 days1999: Unhealthy 5 of 363 days2000: Good 277 of 363 days2000: Moderate 59 of 363 days2000: Unhealthy for Sensitive Groups 24 of 363 days2000: Unhealthy 3 of 363 days2001: Good 317 of 360 days2001: Moderate 36 of 360 days2001: Unhealthy for Sensitive Groups 7 of 360 days20012002: Good 326 of 360 days2002: Moderate 32 of 360 days2002: Unhealthy for Sensitive Groups 1 of 360 days2002: Unhealthy 1 of 360 days2003: Good 304 of 357 days2003: Moderate 39 of 357 days2003: Unhealthy for Sensitive Groups 13 of 357 days2003: Unhealthy 1 of 357 days2004: Good 312 of 349 days2004: Moderate 31 of 349 days2004: Unhealthy for Sensitive Groups 6 of 349 days2005: Good 272 of 357 days2005: Moderate 74 of 357 days2005: Unhealthy for Sensitive Groups 10 of 357 days2005: Unhealthy 1 of 357 days2006: Good 277 of 350 days2006: Moderate 61 of 350 days2006: Unhealthy for Sensitive Groups 11 of 350 days2006: Unhealthy 1 of 350 days20062007: Good 307 of 362 days2007: Moderate 46 of 362 days2007: Unhealthy for Sensitive Groups 8 of 362 days2007: Unhealthy 1 of 362 days2008: Good 314 of 361 days2008: Moderate 45 of 361 days2008: Unhealthy for Sensitive Groups 2 of 361 days2009: Good 317 of 354 days2009: Moderate 35 of 354 days2009: Unhealthy for Sensitive Groups 2 of 354 days2010: Good 312 of 362 days2010: Moderate 48 of 362 days2010: Unhealthy for Sensitive Groups 2 of 362 days2011: Good 310 of 363 days2011: Moderate 45 of 363 days2011: Unhealthy for Sensitive Groups 8 of 363 days20112012: Good 340 of 365 days2012: Moderate 23 of 365 days2012: Unhealthy for Sensitive Groups 2 of 365 days2013: Good 335 of 357 days2013: Moderate 22 of 357 days2014: Good 318 of 344 days2014: Moderate 25 of 344 days2014: Unhealthy 1 of 344 days2015: Good 325 of 345 days2015: Moderate 18 of 345 days2015: Unhealthy for Sensitive Groups 2 of 345 days2016: Good 347 of 366 days2016: Moderate 19 of 366 days20162017: Good 349 of 365 days2017: Moderate 16 of 365 days2018: Good 350 of 364 days2018: Moderate 14 of 364 days2019: Good 344 of 359 days2019: Moderate 15 of 359 days2020: Good 351 of 357 days2020: Moderate 6 of 357 days2021: Good 326 of 330 days2021: Moderate 4 of 330 days20212022: Good 345 of 361 days2022: Moderate 16 of 361 days2023: Good 314 of 351 days2023: Moderate 35 of 351 days2023: Unhealthy for Sensitive Groups 2 of 351 days2024: Good 339 of 363 days2024: Moderate 21 of 363 days2024: Unhealthy for Sensitive Groups 3 of 363 days2025: Good 337 of 359 days2025: Moderate 22 of 359 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 year0501001501983: 90th percentile AQI 581984: 90th percentile AQI 461988: 90th percentile AQI 471989: 90th percentile AQI 741990: 90th percentile AQI 741991: 90th percentile AQI 501992: 90th percentile AQI 461993: 90th percentile AQI 491994: 90th percentile AQI 801995: 90th percentile AQI 1011996: 90th percentile AQI 581997: 90th percentile AQI 711998: 90th percentile AQI 641999: 90th percentile AQI 932000: 90th percentile AQI 872001: 90th percentile AQI 542002: 90th percentile AQI 502003: 90th percentile AQI 712004: 90th percentile AQI 512005: 90th percentile AQI 772006: 90th percentile AQI 802007: 90th percentile AQI 642008: 90th percentile AQI 582009: 90th percentile AQI 512010: 90th percentile AQI 582011: 90th percentile AQI 642012: 90th percentile AQI 472013: 90th percentile AQI 482014: 90th percentile AQI 482015: 90th percentile AQI 462016: 90th percentile AQI 462017: 90th percentile AQI 462018: 90th percentile AQI 442019: 90th percentile AQI 462020: 90th percentile AQI 442021: 90th percentile AQI 412022: 90th percentile AQI 462023: 90th percentile AQI 512024: 90th percentile AQI 482025: 90th percentile AQI 481983: Median AQI 301984: Median AQI 261988: Median AQI 311989: Median AQI 311990: Median AQI 331991: Median AQI 281992: Median AQI 251993: Median AQI 311994: Median AQI 341995: Median AQI 361996: Median AQI 341997: Median AQI 351998: Median AQI 341999: Median AQI 372000: Median AQI 362001: Median AQI 312002: Median AQI 312003: Median AQI 322004: Median AQI 312005: Median AQI 372006: Median AQI 372007: Median AQI 352008: Median AQI 332009: Median AQI 342010: Median AQI 372011: Median AQI 362012: Median AQI 332013: Median AQI 322014: Median AQI 332015: Median AQI 312016: Median AQI 312017: Median AQI 312018: Median AQI 272019: Median AQI 292020: Median AQI 292021: Median AQI 282022: Median AQI 322023: Median AQI 332024: Median AQI 322025: Median AQI 33198319911996200120062011201620212025
  • 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
Ozone359100%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
2025359337220000334884Ozone
20243633392130003248108Ozone
20233513143520003351115Ozone
2022361345160000324693Ozone
202133032640000284158Ozone
202035735160000294490Ozone
2019359344150000294697Ozone
2018364350140000274493Ozone
2017365349160000314680Ozone
2016366347190000314684Ozone
20153453251820003146115Ozone
20143443182501003348154Ozone
20133573352200003248100Ozone
20123653402320003347122Ozone
20113633104580003664136Ozone
20103623124820003758105Ozone
20093543173520003451129Ozone
20083613144520003358115Ozone
20073623074681003564156Ozone
200635027761111003780154Ozone
200535727274101003777156Ozone
20043493123160003151119Ozone
200335730439131003271161Ozone
20023603263211003150166Ozone
20013603173670003154150Ozone
200036327759243003687169Ozone
199936328252245003793192Ozone
199836230540143003464164Ozone
199736229552141003571185Ozone
19963623163862003458161Ozone
1995364279473080036101185Ozone
199436429846182003480172Ozone
19933653332840003149140Ozone
19923593451031002546156Ozone
19913493152770002850115Ozone
199036329943192003374151Ozone
198935428651143003174192Ozone
1988807550000314787Ozone
19849488411002646182Ozone
19831341181240003058147Ozone

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 Louisiana with a similar median AQI in 2025

All monitored counties in Louisiana

Source: U.S. EPA AirData, “Annual AQI by County” files for 1983–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem