SmogRank / Episodes / United States

Eastern United States, March 2026

For 1 day, on 26 March 2026, 11 cities in the United States had PM2.5 at least twice their usual for the time of year. The worst reading was Chattanooga, Tennessee, United States: 43.9 µg/m³ on 26 March, about 5.6× its usual 7.9.

No cause namedWe have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached11in 1 country
Days126 March 2026
Worst day26 March11 cities counted
Furthest above usual5.6×Chattanooga

Day by day

26 March 11 cities at twice their usual or more
MaryvilleAshevilleGreenvilleKingsportLawrencevilleAtlantaCookevilleMcDonoughHickoryNicholasvilleLexington-FayetteCharlotteGadsdenWarner RobinsSaint AndrewsHuntsvilleHendersonvilleElizabethtownHuntingtonNashvilleClemmonsPortsmouthJeffersontownLexingtonColumbiaWinston-SalemSaint MatthewsValley StationDecaturCharlestonLouisvilleTrussvilleJeffersonvilleNew AlbanyBirminghamGreensboroClarksvilleBessemerHueytownSalemFlorenceRoanokeMontgomeryOwensboroSavannahJasperNorth CharlestonEvansvilleDurhamFayettevilleMorrisvilleConwayRaleighPaducahHarrisonburgSpartanburgGainesvilleColumbusMaconKnoxvilleAthensCandler-McAfeeAugustaEast RidgeAshlandChattanooga
23 Mar242526272829
Every measured city in the area, coloured by its PM2.5 that day; a dark ring marks a city at twice its usual or more. Bars: cities counted each day, coloured by their median level. Choose a day or press play; without JavaScript, the days link to that day's world ranking.

How it spread

ChattanoogaChattanooga, 23 March: 9.0 µg/m³Chattanooga, 24 March: 10.2 µg/m³Chattanooga, 25 March: 18.2 µg/m³Chattanooga, 26 March: 43.9 µg/m³, 5.6× its usual 7.9Chattanooga, 27 March: 16.1 µg/m³Chattanooga, 28 March: 4.7 µg/m³Chattanooga, 29 March: 6.7 µg/m³East RidgeEast Ridge, 23 March: 7.6 µg/m³East Ridge, 24 March: 8.9 µg/m³East Ridge, 25 March: 14.9 µg/m³East Ridge, 26 March: 33.4 µg/m³, 3.7× its usual 9.1East Ridge, 27 March: 12.9 µg/m³East Ridge, 28 March: 4.7 µg/m³East Ridge, 29 March: 6.1 µg/m³AugustaAugusta, 23 March: 13.0 µg/m³Augusta, 24 March: 4.2 µg/m³Augusta, 25 March: 14.9 µg/m³Augusta, 26 March: 30.4 µg/m³, 3.7× its usual 8.3Augusta, 27 March: 21.7 µg/m³Augusta, 28 March: 6.3 µg/m³Augusta, 29 March: 5.3 µg/m³Candler-McAfeeCandler-McAfee, 23 March: 10.1 µg/m³Candler-McAfee, 24 March: 5.1 µg/m³Candler-McAfee, 25 March: 20.6 µg/m³Candler-McAfee, 26 March: 30.4 µg/m³, 3.7× its usual 8.2Candler-McAfee, 27 March: 21.3 µg/m³Candler-McAfee, 28 March: 3.4 µg/m³Candler-McAfee, 29 March: 5.3 µg/m³AthensAthens, 23 March: 11.8 µg/m³Athens, 24 March: 6.9 µg/m³Athens, 25 March: 21.2 µg/m³Athens, 26 March: 30.1 µg/m³, 3.7× its usual 8.1Athens, 27 March: 21.7 µg/m³Athens, 28 March: 3.2 µg/m³Athens, 29 March: 4.9 µg/m³AshlandAshland, 23 March: 7.4 µg/m³Ashland, 24 March: 5.7 µg/m³Ashland, 25 March: 13.3 µg/m³Ashland, 26 March: 29.1 µg/m³, 4.8× its usual 6.1Ashland, 27 March: 9.5 µg/m³Ashland, 28 March: 5.3 µg/m³Ashland, 29 March: 8.3 µg/m³MaconMacon, 23 March: 12.7 µg/m³Macon, 24 March: 7.2 µg/m³Macon, 25 March: 14.7 µg/m³Macon, 26 March: 28.9 µg/m³, 3.3× its usual 8.8Macon, 27 March: 29.5 µg/m³Macon, 28 March: 6.0 µg/m³Macon, 29 March: 7.1 µg/m³ColumbusColumbus, 23 March: 14.8 µg/m³Columbus, 24 March: 12.9 µg/m³Columbus, 25 March: 16.8 µg/m³Columbus, 26 March: 26.1 µg/m³, 3.1× its usual 8.3Columbus, 27 March: 14.3 µg/m³Columbus, 28 March: 7.8 µg/m³Columbus, 29 March: 6.7 µg/m³GainesvilleGainesville, 23 March: 10.1 µg/m³Gainesville, 24 March: 5.0 µg/m³Gainesville, 25 March: 13.0 µg/m³Gainesville, 26 March: 25.8 µg/m³, 3.1× its usual 8.2Gainesville, 27 March: 22.6 µg/m³Gainesville, 28 March: 3.3 µg/m³Gainesville, 29 March: 4.7 µg/m³SpartanburgSpartanburg, 23 March: 11.0 µg/m³Spartanburg, 24 March: 3.8 µg/m³Spartanburg, 25 March: 17.0 µg/m³Spartanburg, 26 March: 25.7 µg/m³, 3.1× its usual 8.4Spartanburg, 27 March: 26.4 µg/m³Spartanburg, 28 March: 3.3 µg/m³Spartanburg, 29 March: 5.6 µg/m³KnoxvilleKnoxville, 23 March: 6.9 µg/m³Knoxville, 24 March: 4.0 µg/m³Knoxville, 25 March: 11.2 µg/m³Knoxville, 26 March: 25.3 µg/m³, 3.4× its usual 7.5Knoxville, 27 March: 15.9 µg/m³Knoxville, 28 March: 4.4 µg/m³Knoxville, 29 March: 4.7 µg/m³23 Mar242526272829
Every counted city, in the order the episode reached them, 3 days before to 3 after. Each square is a day, coloured by that day's PM2.5; outlined: at twice the city's usual or more.
Good0–50
Moderate51–100
Sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

Every city it reached

CityDaysHighestUsualAbove usual
ChattanoogaTennessee, United States1 43.926 March7.95.6×
AshlandKentucky, United States1 29.126 March6.14.8×
East RidgeTennessee, United States1 33.426 March9.13.7×
AugustaGeorgia, United States1 30.426 March8.33.7×
Candler-McAfeeGeorgia, United States1 30.426 March8.23.7×
AthensGeorgia, United States1 30.126 March8.13.7×
KnoxvilleTennessee, United States1 25.326 March7.53.4×
MaconGeorgia, United States1 28.926 March8.83.3×
ColumbusGeorgia, United States1 26.126 March8.33.1×
GainesvilleGeorgia, United States1 25.826 March8.23.1×
SpartanburgSouth Carolina, United States1 25.726 March8.43.1×

Daily means in µg/m³, over the days each city counted in this episode. Highest: its highest of those days. Usual: the city's median for the time of year of that day (its days within 21 days of the date, every year, leaving out the week around it). Above usual: its highest day against that, with a usual under 5 µg/m³ taken as 5.

Against other episodes in the United States

Number 89 of 130 episodes in the United States since our records began, by cities reached.

Bars: cities reached; colour: the level of the episode's highest daily reading. All 130.

Use this page

SmogRank, Eastern United States, March 2026: 11 cities with PM2.5 at twice their usual or more, 26 March 2026, smogrank.com/episodes/2026-03-eastern-united-states (accessed 4 October 2026).

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You're welcome to reuse a single chart, image or figure with this citation and a link. Terms.

An episode is a run of days when many cities close to each other (four or more within 350 km on a day, 8 or more in all) each had a daily PM2.5 mean of at least 25 µg/m³ and at least 2 times their usual for that time of year. Found in our own measurements, not picked by hand. How we find episodes. Values are each city's daily mean of its own monitors; causes are the usual kinds for a pattern like this, not a confirmed source.