EnviroNearby

St. John the Baptist Parish, Louisiana air quality history

Daily Air Quality Index summaries from EPA monitors in St. John the Baptist, Louisiana, 1980–2025.

93%
Good days in 2025
34
Median daily AQI, 2025
0
Days above 100 in 2025
364
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for St. John the Baptist, Louisiana on 364 days. 339 of those days (93%) were in the Good range, and the median daily AQI was 34. 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 364 days. Across the years with fuller monitoring, the share of Good days rose: an average of 82% in 1980–1982 versus 90% 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 116 of 147 days1980: Moderate 19 of 147 days1980: Unhealthy for Sensitive Groups 5 of 147 days1980: Unhealthy 6 of 147 days1980: Very Unhealthy 1 of 147 days19801981: Good 225 of 300 days1981: Moderate 55 of 300 days1981: Unhealthy for Sensitive Groups 15 of 300 days1981: Unhealthy 5 of 300 days1982: Good 321 of 349 days1982: Moderate 20 of 349 days1982: Unhealthy for Sensitive Groups 7 of 349 days1982: Unhealthy 1 of 349 days1983: Good 278 of 325 days1983: Moderate 36 of 325 days1983: Unhealthy for Sensitive Groups 8 of 325 days1983: Unhealthy 3 of 325 days1984: Good 293 of 364 days1984: Moderate 48 of 364 days1984: Unhealthy for Sensitive Groups 17 of 364 days1984: Unhealthy 6 of 364 days1985: Good 295 of 353 days1985: Moderate 38 of 353 days1985: Unhealthy for Sensitive Groups 18 of 353 days1985: Unhealthy 2 of 353 days19851986: Good 280 of 360 days1986: Moderate 59 of 360 days1986: Unhealthy for Sensitive Groups 15 of 360 days1986: Unhealthy 5 of 360 days1986: Very Unhealthy 1 of 360 days1987: Good 267 of 359 days1987: Moderate 57 of 359 days1987: Unhealthy for Sensitive Groups 23 of 359 days1987: Unhealthy 12 of 359 days1988: Good 256 of 343 days1988: Moderate 49 of 343 days1988: Unhealthy for Sensitive Groups 25 of 343 days1988: Unhealthy 11 of 343 days1988: Very Unhealthy 2 of 343 days1989: Good 297 of 357 days1989: Moderate 51 of 357 days1989: Unhealthy for Sensitive Groups 8 of 357 days1989: Unhealthy 1 of 357 days1990: Good 306 of 365 days1990: Moderate 51 of 365 days1990: Unhealthy for Sensitive Groups 7 of 365 days1990: Unhealthy 1 of 365 days19901991: Good 311 of 359 days1991: Moderate 39 of 359 days1991: Unhealthy for Sensitive Groups 9 of 359 days1992: Good 315 of 355 days1992: Moderate 30 of 355 days1992: Unhealthy for Sensitive Groups 8 of 355 days1992: Unhealthy 2 of 355 days1993: Good 269 of 339 days1993: Moderate 59 of 339 days1993: Unhealthy for Sensitive Groups 9 of 339 days1993: Unhealthy 2 of 339 days1994: Good 305 of 363 days1994: Moderate 39 of 363 days1994: Unhealthy for Sensitive Groups 15 of 363 days1994: Unhealthy 4 of 363 days1995: Good 270 of 358 days1995: Moderate 50 of 358 days1995: Unhealthy for Sensitive Groups 35 of 358 days1995: Unhealthy 3 of 358 days19951996: Good 308 of 364 days1996: Moderate 43 of 364 days1996: Unhealthy for Sensitive Groups 11 of 364 days1996: Unhealthy 2 of 364 days1997: Good 275 of 364 days1997: Moderate 65 of 364 days1997: Unhealthy for Sensitive Groups 21 of 364 days1997: Unhealthy 3 of 364 days1998: Good 290 of 359 days1998: Moderate 54 of 359 days1998: Unhealthy for Sensitive Groups 11 of 359 days1998: Unhealthy 4 of 359 days1999: Good 271 of 365 days1999: Moderate 61 of 365 days1999: Unhealthy for Sensitive Groups 28 of 365 days1999: Unhealthy 5 of 365 days2000: Good 267 of 361 days2000: Moderate 56 of 361 days2000: Unhealthy for Sensitive Groups 30 of 361 days2000: Unhealthy 8 of 361 days20002001: Good 289 of 354 days2001: Moderate 54 of 354 days2001: Unhealthy for Sensitive Groups 11 of 354 days2002: Good 324 of 361 days2002: Moderate 30 of 361 days2002: Unhealthy for Sensitive Groups 7 of 361 days2003: Good 308 of 362 days2003: Moderate 40 of 362 days2003: Unhealthy for Sensitive Groups 12 of 362 days2003: Unhealthy 2 of 362 days2004: Good 298 of 346 days2004: Moderate 38 of 346 days2004: Unhealthy for Sensitive Groups 10 of 346 days2005: Good 272 of 354 days2005: Moderate 71 of 354 days2005: Unhealthy for Sensitive Groups 10 of 354 days2005: Unhealthy 1 of 354 days20052006: Good 292 of 363 days2006: Moderate 59 of 363 days2006: Unhealthy for Sensitive Groups 10 of 363 days2006: Unhealthy 2 of 363 days2007: Good 301 of 362 days2007: Moderate 44 of 362 days2007: Unhealthy for Sensitive Groups 17 of 362 days2008: Good 315 of 354 days2008: Moderate 35 of 354 days2008: Unhealthy for Sensitive Groups 4 of 354 days2009: Good 310 of 348 days2009: Moderate 33 of 348 days2009: Unhealthy for Sensitive Groups 5 of 348 days2010: Good 297 of 365 days2010: Moderate 61 of 365 days2010: Unhealthy for Sensitive Groups 7 of 365 days20102011: Good 291 of 363 days2011: Moderate 61 of 363 days2011: Unhealthy for Sensitive Groups 10 of 363 days2011: Unhealthy 1 of 363 days2012: Good 284 of 359 days2012: Moderate 65 of 359 days2012: Unhealthy for Sensitive Groups 10 of 359 days2013: Good 332 of 364 days2013: Moderate 30 of 364 days2013: Unhealthy for Sensitive Groups 2 of 364 days2014: Good 322 of 352 days2014: Moderate 29 of 352 days2014: Unhealthy for Sensitive Groups 1 of 352 days2015: Good 341 of 365 days2015: Moderate 22 of 365 days2015: Unhealthy for Sensitive Groups 2 of 365 days20152016: Good 347 of 365 days2016: Moderate 17 of 365 days2016: Unhealthy for Sensitive Groups 1 of 365 days2017: Good 337 of 362 days2017: Moderate 25 of 362 days2018: Good 336 of 359 days2018: Moderate 22 of 359 days2018: Unhealthy for Sensitive Groups 1 of 359 days2019: Good 334 of 364 days2019: Moderate 30 of 364 days2020: Good 341 of 351 days2020: Moderate 10 of 351 days20202021: Good 327 of 336 days2021: Moderate 8 of 336 days2021: Unhealthy for Sensitive Groups 1 of 336 days2022: Good 335 of 351 days2022: Moderate 16 of 351 days2023: Good 315 of 358 days2023: Moderate 39 of 358 days2023: Unhealthy for Sensitive Groups 4 of 358 days2024: Good 320 of 359 days2024: Moderate 37 of 359 days2024: Unhealthy for Sensitive Groups 2 of 359 days2025: Good 339 of 364 days2025: Moderate 25 of 364 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 931981: 90th percentile AQI 841982: 90th percentile AQI 491983: 90th percentile AQI 671984: 90th percentile AQI 841985: 90th percentile AQI 801986: 90th percentile AQI 871987: 90th percentile AQI 1001988: 90th percentile AQI 1121989: 90th percentile AQI 671990: 90th percentile AQI 641991: 90th percentile AQI 611992: 90th percentile AQI 541993: 90th percentile AQI 771994: 90th percentile AQI 711995: 90th percentile AQI 1011996: 90th percentile AQI 671997: 90th percentile AQI 871998: 90th percentile AQI 801999: 90th percentile AQI 972000: 90th percentile AQI 1012001: 90th percentile AQI 712002: 90th percentile AQI 542003: 90th percentile AQI 672004: 90th percentile AQI 612005: 90th percentile AQI 772006: 90th percentile AQI 742007: 90th percentile AQI 672008: 90th percentile AQI 512009: 90th percentile AQI 542010: 90th percentile AQI 672011: 90th percentile AQI 842012: 90th percentile AQI 672013: 90th percentile AQI 502014: 90th percentile AQI 492015: 90th percentile AQI 482016: 90th percentile AQI 482017: 90th percentile AQI 472018: 90th percentile AQI 482019: 90th percentile AQI 482020: 90th percentile AQI 452021: 90th percentile AQI 452022: 90th percentile AQI 472023: 90th percentile AQI 582024: 90th percentile AQI 512025: 90th percentile AQI 481980: Median AQI 301981: Median AQI 371982: Median AQI 301983: Median AQI 311984: Median AQI 361985: Median AQI 331986: Median AQI 361987: Median AQI 391988: Median AQI 351989: Median AQI 311990: Median AQI 351991: Median AQI 321992: Median AQI 331993: Median AQI 361994: Median AQI 341995: Median AQI 371996: Median AQI 331997: Median AQI 361998: Median AQI 341999: Median AQI 382000: Median AQI 382001: Median AQI 362002: Median AQI 332003: Median AQI 332004: Median AQI 322005: Median AQI 392006: Median AQI 382007: Median AQI 362008: Median AQI 322009: Median AQI 352010: Median AQI 382011: Median AQI 372012: Median AQI 402013: Median AQI 362014: Median AQI 352015: Median AQI 332016: Median AQI 352017: Median AQI 332018: Median AQI 312019: Median AQI 332020: Median AQI 312021: Median AQI 312022: Median AQI 332023: Median AQI 352024: Median AQI 362025: Median AQI 341980198519901995200020052010201520202025
  • 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
Ozone364100%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
2025364339250000344887Ozone
20243593203720003651105Ozone
20233583153940003558112Ozone
2022351335160000334780Ozone
2021336327810003145108Ozone
2020351341100000314580Ozone
2019364334300000334893Ozone
20183593362210003148108Ozone
20173623372500003347100Ozone
20163653471710003548105Ozone
20153653412220003348105Ozone
20143523222910003549108Ozone
20133643323020003650105Ozone
201235928465100004067129Ozone
201136329161101003784151Ozone
20103652976170003867115Ozone
20093483103350003554133Ozone
20083543153540003251112Ozone
200736230144170003667147Ozone
200636329259102003874164Ozone
200535427271101003977151Ozone
200434629838100003261133Ozone
200336230840122003367154Ozone
20023613243070003354133Ozone
200135428954110003671150Ozone
2000361267563080038101192Ozone
199936527161285003897169Ozone
199835929054114003480195Ozone
199736427565213003687169Ozone
199636430843112003367190Ozone
1995358270503530037101192Ozone
199436330539154003471179Ozone
19933392695992003677179Ozone
19923553153082003354197Ozone
19913593113990003261133Ozone
19903653065171003564177Ozone
19893572975181003167156Ozone
19883432564925112035112206Ozone
19873592675723120039100182Ozone
198636028059155103687201Ozone
198535329538182003380174Ozone
198436429348176003684174Ozone
19833252783683003167192Ozone
19823493212071003049164Ozone
198130022555155003784187Ozone
19801471161956103093213Ozone

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 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