What was the worst air-quality day in Jackson?

June 24, 2005, when daily PM2.5 reached 49.4 µg/m³ (AQI 135), about 2.2 cigarette-equivalents. It ranks first of 5,567 monitored days since 1999.

What is the highest AQI recorded in Jackson?

On the worst day, the daily PM2.5 AQI reached 135 (Unhealthy for sensitive groups). EPA's official metro AQI, which uses the single worst monitor of any pollutant, peaked at 177 on August 7, 1999.

Were these days caused by wildfire smoke?

This page ranks measured PM2.5 without assigning a cause: a high day can be smoke, fireworks, dust, an inversion, or industry. A separate wildfire-smoke event ranking, using a published attribution method with its version disclosed, is the next layer of this catalog.

How often does Jackson get air this bad?

Rarely. The record sits at the far end of 5,567 measured days; Jackson averages 0 "unhealthy" days a year.

Why did different apps show different numbers that day?

Concentration (µg/m³) and AQI are different scales; hourly, NowCast, and daily values answer different questions; a single monitor differs from a citywide composite; and live feeds get revised when EPA certifies data. This page uses the certified daily record, with the provisional tail labeled.

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Historical PM2.5 records

Jackson's worst air quality days

#98 of 100 US metros by worst day · Jackson, MS metro area

Based on the available regulatory-monitor record since 1999, June 24, 2005 ranks as Jackson's most severe daily PM2.5 day: 49.4 µg/m³ (AQI 135, unhealthy for sensitive groups), about 2.2 cigarettes in a day.

Daily rank: #1
Period of record: Since 1999
Peak daily PM2.5: 49.4 µg/m³
About: 2.2 cigarettes
Status: Finalized

Current conditions on the smoke map → Data through May 31, 2026 · page built July 26, 2026

Show

The worst-hit part of the metro: its highest credible monitor each day.

How this is measured sources, the daily measure, and what this ranking is not

Source. Daily PM2.5 from the U.S. EPA Air Quality System (AQS) , back to 1999, across 6 EPA monitors in the Jackson, MS metro area (CBSA). Days after May 31, 2026 are preliminary AirNow readings, marked provisional, and re-rank once EPA certifies them (usually the following spring).

The daily measure. "Worst area" is the metro's highest credible monitor each day, with lone bad-monitor spikes dropped (the raw single-monitor max before that filter is in the data but not charted). "Metro average" averages every monitor. The unit choice re-reads the same value as µg/m³, cigarette-equivalents (PM2.5 ÷ 22, Berkeley Earth, an illustration rather than a medical reading), or the EPA 2024 PM2.5 AQI.

Official AQI. EPA's reported metro AQI uses the single worst monitor of any pollutant, so it can run higher than the values here. The highest official daily AQI among the ranked days is 177 on August 7, 1999 (defining pollutant Ozone).

What this ranking is not. It does not attribute days to wildfire smoke: a high-PM2.5 day can be dust, fireworks, an inversion, or industry. The wildfire-smoke event ranking below arrives with a published attribution method.

Jackson's monitoring record is thinner than most, 5,567 days since 1999, with gaps between them. The ranking is real, but treat it as indicative rather than a complete accounting.

What were Jackson's worst days?

Rank	Date	Daily PM2.5
#1	June 24, 2005	49.4 µg/m³
#2	September 11, 2002	48.2 µg/m³
#3	August 7, 1999	45.5 µg/m³
#4	July 20, 2000	41.7 µg/m³
#5	October 30, 2000	41.4 µg/m³
#6	June 26, 2020	40.7 µg/m³
#7	July 24, 2001	40.3 µg/m³
#8	August 15, 2018	40.1 µg/m³
#9	May 12, 2000	39.4 µg/m³
#10	October 27, 2000	38.5 µg/m³
#11	February 19, 2011	38.2 µg/m³
#12	September 10, 2005	37.6 µg/m³
#13	February 28, 2023	37.6 µg/m³
#14	June 13, 2022	37.2 µg/m³
#15	August 14, 2001	37.1 µg/m³

What caused Jackson's worst days?

The event catalog has named 5 episodes affecting Jackson, each resolved to a cause only where retained evidence supports it: EPA monitor qualifiers, NWS alerts, agency statements, and reporting. The ranking above stays cause-neutral; this is where the causes live.

Prescribed fire 2026-03-01 prescribed-fire smoke episode affecting Jackson, MS Mar 1, 2026 · 35.8 µg/m³ here , #17 all-time
Prescribed fire 2023 February 28 Jackson prescribed-fire smoke episode Feb 28, 2023 · 37.6 µg/m³ here , #13 all-time · from Jackson, MS
Dust June 2022 Gulf and southern Plains Saharan-dust episode Jun 13, 2022 · 37.2 µg/m³ here , #14 all-time · from Sahara
Other 2022-02-15 Jackson, MS another explicitly identified source episode Feb 15, 2022 · 35.6 µg/m³ here , #18 all-time
Dust Late-June 2020 Saharan dust plume Jun 26, 2020 · 40.7 µg/m³ here , #6 all-time · from Austin-Round Rock, TX

every named episode and its evidence is in the event catalog.

How does it compare?

The record is 2% higher than the next-worst day: 49.4 µg/m³ (June 24, 2005) against 48.2 µg/m³ (September 11, 2002).

How unusual is air like this?

5× a typical day here, at the record

0 days at "unhealthy" in Jackson's record

2 µg/m³49 µg/m³

Every measured day near Jackson, by daily PM2.5; the record stands far out on the right. 18 days at "unhealthy for sensitive groups" or worse, 0 at "unhealthy", 0 at "very unhealthy" (2024 EPA thresholds, across 5,567 measured days).

Year by year (1999–2026)

Worst single day each year, by the selected measure.

Why did reported numbers differ?

During a major event, AirNow, weather apps, news reports, and neighborhood monitors can all show different figures at the same moment. All of them can be right:

Concentration vs AQI. µg/m³ is the measurement; AQI is a 0 to 500 index derived from it. "330 µg/m³" and "AQI 500" can describe the same air.
Hourly vs NowCast vs daily. An hourly peak, the NowCast rolling estimate apps display, and the full-day average answer different questions; this page ranks full days.
One monitor vs a composite. A single sensor can read far above or below a citywide figure. The measure toggle above shows both framings.
Live vs certified. Real-time feeds get corrected when EPA certifies data months later, which is why recent days here carry a provisional label.

What about indoors?

Citywide monitors can tell you what happened outside. They cannot tell you what happened inside a particular home, school, or facility: filtration, ventilation, and building operation decide that. During and after days like the ones above, outdoor particles become an indoor load question.

Check current conditions and the next clean-air window → Estimate recent filter load where you are →

Common questions

What was the worst air-quality day in Jackson?: June 24, 2005, when daily PM2.5 reached 49.4 µg/m³ (AQI 135), about 2.2 cigarette-equivalents. It ranks first of 5,567 monitored days since 1999.
What is the highest AQI recorded in Jackson?: On the worst day, the daily PM2.5 AQI reached 135 (Unhealthy for sensitive groups). EPA's official metro AQI, which uses the single worst monitor of any pollutant, peaked at 177 on August 7, 1999.
Were these days caused by wildfire smoke?: This page ranks measured PM2.5 without assigning a cause: a high day can be smoke, fireworks, dust, an inversion, or industry. A separate wildfire-smoke event ranking, using a published attribution method with its version disclosed, is the next layer of this catalog.
How often does Jackson get air this bad?: Rarely. The record sits at the far end of 5,567 measured days; Jackson averages 0 "unhealthy" days a year.
Why did different apps show different numbers that day?: Concentration (µg/m³) and AQI are different scales; hourly, NowCast, and daily values answer different questions; a single monitor differs from a citywide composite; and live feeds get revised when EPA certifies data. This page uses the certified daily record, with the provisional tail labeled.

Data and citation

Ranked days for both measures are downloadable, with units and status flags: jackson.csv. Source: U.S. EPA Air Quality System (AQS) daily PM2.5, with preliminary AirNow readings for the uncertified tail. Cite as:

IAQng Air Records: Jackson, MS. iaqng.com/records/jackson. Data: U.S. EPA AQS and AirNow. Accessed July 26, 2026.