SmogRank / Episodes / United States
Eastern United States, March 2023
For 2 days, from 21 to 22 March 2023, 16 cities in the United States had PM2.5 at least twice their usual for the time of year. The worst reading was Albany, Georgia, United States: 53.3 µg/m³ on 21 March, about 5.2× its usual 10.3.
No cause named We have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached 16 in 1 country
Days 2 21 to 22 March 2023
Worst day 22 March 12 cities counted
Furthest above usual 5.2× Albany
Day by day
Play 22 March 12 cities at twice their usual or more
Atlanta McDonough Warner Robins Montgomery Maryville Hueytown Decatur Knoxville Cookeville Augusta Asheville Columbia Spartanburg Nashville Hendersonville Saint Andrews Hickory Savannah Brunswick Charlotte Jackson North Charleston Lexington Florence Dyersburg Bartlett Hernando Greensboro Birmingham East Ridge Chattanooga Hattiesburg Greenville Gainesville Macon Athens Gadsden Winston-Salem Lawrenceville Phenix City Huntsville Clemmons Trussville Albany 18 Mar 19 20 21 22 23 24 25 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
Albany Albany, 18 March: 4.7 µg/m³, 0.5× usual Albany, 19 March: 6.2 µg/m³, 0.6× usual Albany, 20 March: 24.2 µg/m³, 2.3× usual Albany, 21 March: 53.3 µg/m³, 5.2× usual Albany, 22 March: 17.5 µg/m³, 1.7× usual Albany, 23 March: 30.4 µg/m³, 3.0× usual Albany, 24 March: 16.6 µg/m³, 1.6× usual Albany, 25 March: 8.0 µg/m³, 0.8× usual Phenix City Phenix City, 18 March: 4.0 µg/m³, 0.5× usual Phenix City, 19 March: 6.5 µg/m³, 0.8× usual Phenix City, 20 March: 10.0 µg/m³, 1.2× usual Phenix City, 21 March: 33.3 µg/m³, 3.9× usual Phenix City, 22 March: 17.8 µg/m³, 2.1× usual Phenix City, 23 March: 22.6 µg/m³, 2.6× usual Phenix City, 24 March: 16.9 µg/m³, 2.0× usual Phenix City, 25 March: 8.1 µg/m³, 0.9× usual Lawrenceville Lawrenceville, 18 March: no reading Lawrenceville, 19 March: 4.9 µg/m³, 0.6× usual Lawrenceville, 20 March: no reading Lawrenceville, 21 March: 30.0 µg/m³, 3.9× usual Lawrenceville, 22 March: 28.9 µg/m³, 3.8× usual Lawrenceville, 23 March: no reading Lawrenceville, 24 March: 17.5 µg/m³, 2.3× usual Lawrenceville, 25 March: 7.8 µg/m³, 1.0× usual Macon Macon, 18 March: no reading Macon, 19 March: 5.0 µg/m³, 0.6× usual Macon, 20 March: no reading Macon, 21 March: 28.7 µg/m³, 3.2× usual Macon, 22 March: 12.6 µg/m³, 1.4× usual Macon, 23 March: no reading Macon, 24 March: 16.2 µg/m³, 1.8× usual Macon, 25 March: 9.6 µg/m³, 1.1× usual Hattiesburg Hattiesburg, 18 March: 4.3 µg/m³, 0.5× usual Hattiesburg, 19 March: 5.1 µg/m³, 0.6× usual Hattiesburg, 20 March: 7.8 µg/m³, 0.9× usual Hattiesburg, 21 March: 27.7 µg/m³, 3.0× usual Hattiesburg, 22 March: 13.6 µg/m³, 1.5× usual Hattiesburg, 23 March: 14.3 µg/m³, 1.6× usual Hattiesburg, 24 March: 8.4 µg/m³, 0.9× usual Hattiesburg, 25 March: 11.0 µg/m³, 1.2× usual Birmingham Birmingham, 18 March: no reading Birmingham, 19 March: 7.7 µg/m³, 0.7× usual Birmingham, 20 March: no reading Birmingham, 21 March: 25.4 µg/m³, 2.4× usual Birmingham, 22 March: 27.4 µg/m³, 2.6× usual Birmingham, 23 March: no reading Birmingham, 24 March: 11.9 µg/m³, 1.1× usual Birmingham, 25 March: 10.3 µg/m³, 1.0× usual Trussville Trussville, 18 March: 4.5 µg/m³, 0.6× usual Trussville, 19 March: 5.5 µg/m³, 0.7× usual Trussville, 20 March: 6.8 µg/m³, 0.9× usual Trussville, 21 March: 19.3 µg/m³, 2.4× usual Trussville, 22 March: 35.1 µg/m³, 4.4× usual Trussville, 23 March: 17.6 µg/m³, 2.2× usual Trussville, 24 March: 12.1 µg/m³, 1.5× usual Trussville, 25 March: 8.1 µg/m³, 1.0× usual Athens Athens, 18 March: no reading Athens, 19 March: 5.3 µg/m³, 0.6× usual Athens, 20 March: no reading Athens, 21 March: 15.0 µg/m³, 1.8× usual Athens, 22 March: 29.8 µg/m³, 3.6× usual Athens, 23 March: no reading Athens, 24 March: 30.6 µg/m³, 3.7× usual Athens, 25 March: 8.1 µg/m³, 1.0× usual Gadsden Gadsden, 18 March: no reading Gadsden, 19 March: 4.8 µg/m³, 0.6× usual Gadsden, 20 March: no reading Gadsden, 21 March: 17.1 µg/m³, 2.1× usual Gadsden, 22 March: 29.6 µg/m³, 3.7× usual Gadsden, 23 March: no reading Gadsden, 24 March: 15.3 µg/m³, 1.9× usual Gadsden, 25 March: 7.4 µg/m³, 0.9× usual Huntsville Huntsville, 18 March: no reading Huntsville, 19 March: 6.5 µg/m³, 0.9× usual Huntsville, 20 March: no reading Huntsville, 21 March: 14.3 µg/m³, 2.0× usual Huntsville, 22 March: 29.1 µg/m³, 4.1× usual Huntsville, 23 March: no reading Huntsville, 24 March: 11.3 µg/m³, 1.6× usual Huntsville, 25 March: 7.5 µg/m³, 1.1× usual Clemmons Clemmons, 18 March: 3.6 µg/m³, 0.6× usual Clemmons, 19 March: 4.7 µg/m³, 0.7× usual Clemmons, 20 March: 5.8 µg/m³, 0.9× usual Clemmons, 21 March: 13.6 µg/m³, 2.1× usual Clemmons, 22 March: 28.2 µg/m³, 4.3× usual Clemmons, 23 March: 16.9 µg/m³, 2.6× usual Clemmons, 24 March: 16.9 µg/m³, 2.6× usual Clemmons, 25 March: 7.7 µg/m³, 1.2× usual East Ridge East Ridge, 18 March: 4.8 µg/m³, 0.5× usual East Ridge, 19 March: 5.8 µg/m³, 0.6× usual East Ridge, 20 March: 8.6 µg/m³, 1.0× usual East Ridge, 21 March: 18.0 µg/m³, 2.0× usual East Ridge, 22 March: 27.4 µg/m³, 3.0× usual East Ridge, 23 March: 19.8 µg/m³, 2.2× usual East Ridge, 24 March: 14.6 µg/m³, 1.6× usual East Ridge, 25 March: 9.1 µg/m³, 1.0× usual Greenville Greenville, 18 March: 3.7 µg/m³, 0.5× usual Greenville, 19 March: 5.7 µg/m³, 0.7× usual Greenville, 20 March: 8.2 µg/m³, 1.0× usual Greenville, 21 March: 14.4 µg/m³, 1.8× usual Greenville, 22 March: 26.3 µg/m³, 3.2× usual Greenville, 23 March: 17.5 µg/m³, 2.1× usual Greenville, 24 March: 24.3 µg/m³, 3.0× usual Greenville, 25 March: 9.0 µg/m³, 1.1× usual Gainesville Gainesville, 18 March: 4.2 µg/m³, 0.5× usual Gainesville, 19 March: 5.1 µg/m³, 0.6× usual Gainesville, 20 March: 7.9 µg/m³, 1.0× usual Gainesville, 21 March: 14.0 µg/m³, 1.7× usual Gainesville, 22 March: 26.2 µg/m³, 3.2× usual Gainesville, 23 March: 17.9 µg/m³, 2.2× usual Gainesville, 24 March: 18.1 µg/m³, 2.2× usual Gainesville, 25 March: 9.1 µg/m³, 1.1× usual Winston-Salem Winston-Salem, 18 March: 3.5 µg/m³, 0.5× usual Winston-Salem, 19 March: 4.9 µg/m³, 0.7× usual Winston-Salem, 20 March: 5.9 µg/m³, 0.9× usual Winston-Salem, 21 March: 11.3 µg/m³, 1.7× usual Winston-Salem, 22 March: 25.8 µg/m³, 3.8× usual Winston-Salem, 23 March: 17.6 µg/m³, 2.6× usual Winston-Salem, 24 March: 18.4 µg/m³, 2.7× usual Winston-Salem, 25 March: 7.8 µg/m³, 1.1× usual Chattanooga Chattanooga, 18 March: no reading Chattanooga, 19 March: 5.3 µg/m³, 0.6× usual Chattanooga, 20 March: no reading Chattanooga, 21 March: 15.5 µg/m³, 1.9× usual Chattanooga, 22 March: 25.2 µg/m³, 3.0× usual Chattanooga, 23 March: no reading Chattanooga, 24 March: 14.0 µg/m³, 1.7× usual Chattanooga, 25 March: 8.1 µg/m³, 1.0× usual 18 Mar 19 20 21 22 23 24 25 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. Good 0–50
Moderate 51–100
Sensitive groups 101–150
Unhealthy 151–200
Very unhealthy 201–300
Hazardous 301+
Every city it reached
City Days Highest Usual Above usual
Albany Georgia, United States 1 21 March 10.3 5.2× Trussville Alabama, United States 1 22 March 8.0 4.4× Clemmons North Carolina, United States 1 22 March 6.5 4.3× Huntsville Alabama, United States 1 22 March 7.1 4.1× Lawrenceville Georgia, United States 2 21 March 7.7 3.9× Phenix City Alabama, United States 1 21 March 8.6 3.9× Winston-Salem North Carolina, United States 1 22 March 6.8 3.8× Gadsden Alabama, United States 1 22 March 8.0 3.7× Athens Georgia, United States 1 24 March 8.3 3.7× Macon Georgia, United States 1 21 March 8.9 3.2× Greenville South Carolina, United States 1 22 March 8.2 3.2× Gainesville Georgia, United States 1 22 March 8.3 3.2× East Ridge Tennessee, United States 1 22 March 9.0 3.0× Hattiesburg Mississippi, United States 1 21 March 9.1 3.0× Chattanooga Tennessee, United States 1 22 March 8.3 3.0× Birmingham Alabama, United States 2 22 March 10.5 2.6×
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 23 of 41 episodes in the United States since our records began, by cities reached.
North-eastern United States and Canada, June and July 2023 279 North-eastern United States and Canada, May and June 2023 260 North-eastern United States and Canada, July 2023 241 North-eastern United States and Canada, June 2023 161 North-western United States and Canada, August 2023 110 North-eastern United States and Canada, July 2023 75 Western United States, September 2023 61 South-eastern United States, October 2023 47 North-eastern United States, July 2023 46 North-western United States and Canada, May 2023 42 Western United States, December 2023 32 Northern United States, January 2023 32 Eastern United States, March 2023 16 Bars: cities reached; colour: the level of the episode's highest daily reading. All 41 .
Use this page SmogRank, Eastern United States, March 2023: 16 cities with PM2.5 at twice their usual or more, 21 to 22 March 2023, smogrank.com/episodes/2023-03-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.
