SmogRank / Episodes / United States

Eastern United States, February 2026

For 1 day, on 25 February 2026, 8 cities in the United States had PM2.5 at least twice their usual for the time of year. The worst reading was Wake Forest, North Carolina, United States: 40.1 µg/m³ on 25 February, about 5.1× its usual 7.8.

No cause namedWe have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached8in 1 country
Days125 February 2026
Worst day25 February8 cities counted
Furthest above usual5.1×Wake Forest

Day by day

25 February 8 cities at twice their usual or more
Saint AndrewsAugustaCharlotteAshevilleHickoryGainesvilleLawrencevilleFlorenceLexingtonClemmonsKingsportWinston-SalemMcDonoughMaryvilleCandler-McAfeeSavannahNorth CharlestonWarner RobinsKnoxvilleAtlantaGreensboroConwayFayettevilleMorrisvilleEast RidgeColumbusClaytonCookevilleGadsdenHuntsvilleGreenvilleRoanoke RapidsTrussvilleMontgomeryBirminghamHendersonvilleNashvilleMaconGreenvilleDurhamAthensSpartanburgRaleighChattanoogaWake Forest
22 Feb232425262728
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

Wake ForestWake Forest, 22 February: 4.1 µg/m³, 0.5× usualWake Forest, 23 February: 3.3 µg/m³, 0.4× usualWake Forest, 24 February: 5.3 µg/m³, 0.7× usualWake Forest, 25 February: 40.1 µg/m³, 5.1× usualWake Forest, 26 February: 22.0 µg/m³, 2.8× usualWake Forest, 27 February: 29.5 µg/m³, 3.8× usualWake Forest, 28 February: 17.2 µg/m³, 2.2× usualSpartanburgSpartanburg, 22 February: 3.7 µg/m³, 0.4× usualSpartanburg, 23 February: 3.9 µg/m³, 0.4× usualSpartanburg, 24 February: 18.2 µg/m³, 2.0× usualSpartanburg, 25 February: 31.2 µg/m³, 3.5× usualSpartanburg, 26 February: 13.7 µg/m³, 1.5× usualSpartanburg, 27 February: 7.5 µg/m³, 0.8× usualSpartanburg, 28 February: 7.2 µg/m³, 0.8× usualDurhamDurham, 22 February: 3.8 µg/m³, 0.5× usualDurham, 23 February: 3.5 µg/m³, 0.4× usualDurham, 24 February: 4.5 µg/m³, 0.5× usualDurham, 25 February: 27.3 µg/m³, 3.3× usualDurham, 26 February: no readingDurham, 27 February: 13.1 µg/m³, 1.6× usualDurham, 28 February: 9.1 µg/m³, 1.1× usualChattanoogaChattanooga, 22 February: 5.6 µg/m³, 0.8× usualChattanooga, 23 February: 6.8 µg/m³, 1.0× usualChattanooga, 24 February: 12.6 µg/m³, 1.9× usualChattanooga, 25 February: 26.8 µg/m³, 4.0× usualChattanooga, 26 February: 11.4 µg/m³, 1.7× usualChattanooga, 27 February: 5.8 µg/m³, 0.9× usualChattanooga, 28 February: 11.6 µg/m³, 1.7× usualMaconMacon, 22 February: 3.8 µg/m³, 0.4× usualMacon, 23 February: 6.0 µg/m³, 0.6× usualMacon, 24 February: 20.5 µg/m³, 2.2× usualMacon, 25 February: 25.9 µg/m³, 2.8× usualMacon, 26 February: 6.4 µg/m³, 0.7× usualMacon, 27 February: 9.1 µg/m³, 1.0× usualMacon, 28 February: 7.8 µg/m³, 0.8× usualRaleighRaleigh, 22 February: 3.2 µg/m³, 0.5× usualRaleigh, 23 February: 3.0 µg/m³, 0.5× usualRaleigh, 24 February: 5.2 µg/m³, 0.8× usualRaleigh, 25 February: 25.7 µg/m³, 3.9× usualRaleigh, 26 February: 10.6 µg/m³, 1.6× usualRaleigh, 27 February: 14.1 µg/m³, 2.1× usualRaleigh, 28 February: 10.7 µg/m³, 1.6× usualGreenvilleGreenville, 22 February: 3.6 µg/m³, 0.4× usualGreenville, 23 February: 3.4 µg/m³, 0.4× usualGreenville, 24 February: 12.4 µg/m³, 1.4× usualGreenville, 25 February: 25.6 µg/m³, 2.9× usualGreenville, 26 February: 12.5 µg/m³, 1.4× usualGreenville, 27 February: 7.9 µg/m³, 0.9× usualGreenville, 28 February: 9.5 µg/m³, 1.1× usualAthensAthens, 22 February: 3.9 µg/m³, 0.5× usualAthens, 23 February: 3.9 µg/m³, 0.5× usualAthens, 24 February: 14.6 µg/m³, 2.0× usualAthens, 25 February: 25.1 µg/m³, 3.4× usualAthens, 26 February: 5.1 µg/m³, 0.7× usualAthens, 27 February: 4.2 µg/m³, 0.6× usualAthens, 28 February: 8.0 µg/m³, 1.1× usual22 Feb232425262728
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
Wake ForestNorth Carolina, United States1 40.125 February7.85.1×
ChattanoogaTennessee, United States1 26.825 February6.74.0×
RaleighNorth Carolina, United States1 25.725 February6.63.9×
SpartanburgSouth Carolina, United States1 31.225 February9.03.5×
AthensGeorgia, United States1 25.125 February7.43.4×
DurhamNorth Carolina, United States1 27.325 February8.23.3×
GreenvilleSouth Carolina, United States1 25.625 February8.82.9×
MaconGeorgia, United States1 25.925 February9.42.8×

Daily means in µg/m³. Usual: the city's median for this time of year (its days within 21 days of the date, every year, leaving out the week around it). Above usual: its highest day against that.

Against other episodes in the United States

Number 87 of 98 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 98.

Use this page

SmogRank, Eastern United States, February 2026: 8 cities with PM2.5 at twice their usual or more, 25 February 2026, smogrank.com/episodes/2026-02-eastern-united-states (accessed 2 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.