SmogRank / Episodes / United States
Eastern United States, March 2024
For 3 days, from 13 to 15 March 2024, 32 cities in the United States had PM2.5 at least twice their usual for the time of year. The worst reading was Saint Andrews, South Carolina, United States: 53.3 µg/m³ on 14 March, about 6.8× its usual 7.8.
No cause named We have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached 32 in 1 country
Days 3 13 to 15 March 2024
Worst day 14 March 19 cities counted
Furthest above usual 6.8× Saint Andrews
Day by day
Play 14 March 19 cities at twice their usual or more
North Charleston Asheville McDonough Brunswick Fayetteville Candler-McAfee Kingsport Atlanta Maryville Clayton Wake Forest Jacksonville Roanoke East Ridge Chattanooga Greenville Tallahassee Gadsden Cookeville Montgomery Huntsville Hopewell Birmingham Hueytown Decatur Hendersonville Nashville Columbia Clarksville Midway Ferry Pass Lawrenceville Trussville Albany Knoxville Valdosta Lexington Charlotte Savannah Augusta Spartanburg Macon Kennesaw Durham Gainesville Phenix City Chesapeake Raleigh Greensboro Greenville Florence Conway Warner Robins Morrisville Hickory Columbus Roanoke Rapids East Hampton Forest Park Athens Clemmons Winston-Salem Saint Andrews 10 Mar 11 12 13 14 15 16 17 18 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
Columbus Columbus, 10 March: 3.1 µg/m³, 0.3× usual Columbus, 11 March: 5.4 µg/m³, 0.5× usual Columbus, 12 March: 21.2 µg/m³, 2.0× usual Columbus, 13 March: 44.1 µg/m³, 4.2× usual Columbus, 14 March: 41.3 µg/m³, 4.0× usual Columbus, 15 March: 14.7 µg/m³, 1.4× usual Columbus, 16 March: 5.4 µg/m³, 0.5× usual Columbus, 17 March: 5.7 µg/m³, 0.5× usual Columbus, 18 March: 5.3 µg/m³, 0.5× usual Albany Albany, 10 March: 3.2 µg/m³, 0.3× usual Albany, 11 March: 4.9 µg/m³, 0.4× usual Albany, 12 March: 22.7 µg/m³, 2.0× usual Albany, 13 March: 34.3 µg/m³, 3.1× usual Albany, 14 March: 29.3 µg/m³, 2.6× usual Albany, 15 March: 25.6 µg/m³, 2.3× usual Albany, 16 March: 6.6 µg/m³, 0.6× usual Albany, 17 March: 6.4 µg/m³, 0.6× usual Albany, 18 March: 5.4 µg/m³, 0.5× usual Saint Andrews Saint Andrews, 10 March: 2.7 µg/m³, 0.3× usual Saint Andrews, 11 March: 3.1 µg/m³, 0.4× usual Saint Andrews, 12 March: 11.2 µg/m³, 1.4× usual Saint Andrews, 13 March: 32.2 µg/m³, 4.1× usual Saint Andrews, 14 March: 53.3 µg/m³, 6.8× usual Saint Andrews, 15 March: 22.0 µg/m³, 2.8× usual Saint Andrews, 16 March: 6.2 µg/m³, 0.8× usual Saint Andrews, 17 March: 6.6 µg/m³, 0.8× usual Saint Andrews, 18 March: 7.1 µg/m³, 0.9× usual Phenix City Phenix City, 10 March: 3.0 µg/m³, 0.3× usual Phenix City, 11 March: 3.5 µg/m³, 0.4× usual Phenix City, 12 March: 16.3 µg/m³, 1.8× usual Phenix City, 13 March: 31.1 µg/m³, 3.4× usual Phenix City, 14 March: 35.9 µg/m³, 3.9× usual Phenix City, 15 March: 16.8 µg/m³, 1.8× usual Phenix City, 16 March: 5.6 µg/m³, 0.6× usual Phenix City, 17 March: 6.6 µg/m³, 0.7× usual Phenix City, 18 March: 5.6 µg/m³, 0.6× usual Warner Robins Warner Robins, 10 March: 2.5 µg/m³, 0.3× usual Warner Robins, 11 March: 2.9 µg/m³, 0.3× usual Warner Robins, 12 March: 10.0 µg/m³, 1.1× usual Warner Robins, 13 March: 30.5 µg/m³, 3.3× usual Warner Robins, 14 March: 37.5 µg/m³, 4.1× usual Warner Robins, 15 March: 24.5 µg/m³, 2.7× usual Warner Robins, 16 March: 5.2 µg/m³, 0.6× usual Warner Robins, 17 March: 5.3 µg/m³, 0.6× usual Warner Robins, 18 March: 4.5 µg/m³, 0.5× usual Augusta Augusta, 10 March: 1.9 µg/m³, 0.2× usual Augusta, 11 March: 5.7 µg/m³, 0.6× usual Augusta, 12 March: 14.3 µg/m³, 1.5× usual Augusta, 13 March: 28.3 µg/m³, 2.9× usual Augusta, 14 March: 33.3 µg/m³, 3.5× usual Augusta, 15 March: 21.3 µg/m³, 2.2× usual Augusta, 16 March: 4.9 µg/m³, 0.5× usual Augusta, 17 March: 5.7 µg/m³, 0.6× usual Augusta, 18 March: 5.3 µg/m³, 0.6× usual Macon Macon, 10 March: 2.5 µg/m³, 0.2× usual Macon, 11 March: 3.3 µg/m³, 0.3× usual Macon, 12 March: 12.6 µg/m³, 1.2× usual Macon, 13 March: 28.2 µg/m³, 2.7× usual Macon, 14 March: 37.3 µg/m³, 3.6× usual Macon, 15 March: 25.4 µg/m³, 2.5× usual Macon, 16 March: 5.5 µg/m³, 0.5× usual Macon, 17 March: 6.6 µg/m³, 0.6× usual Macon, 18 March: 5.2 µg/m³, 0.5× usual Trussville Trussville, 10 March: 4.4 µg/m³, 0.5× usual Trussville, 11 March: 5.6 µg/m³, 0.6× usual Trussville, 12 March: 10.4 µg/m³, 1.2× usual Trussville, 13 March: 27.4 µg/m³, 3.0× usual Trussville, 14 March: 22.4 µg/m³, 2.5× usual Trussville, 15 March: 7.3 µg/m³, 0.8× usual Trussville, 16 March: 7.9 µg/m³, 0.9× usual Trussville, 17 March: 8.0 µg/m³, 0.9× usual Trussville, 18 March: 4.9 µg/m³, 0.5× usual Athens Athens, 10 March: 2.0 µg/m³, 0.2× usual Athens, 11 March: 2.4 µg/m³, 0.3× usual Athens, 12 March: 5.0 µg/m³, 0.6× usual Athens, 13 March: 14.0 µg/m³, 1.6× usual Athens, 14 March: 41.6 µg/m³, 4.9× usual Athens, 15 March: 28.8 µg/m³, 3.4× usual Athens, 16 March: 4.6 µg/m³, 0.5× usual Athens, 17 March: 5.0 µg/m³, 0.6× usual Athens, 18 March: 4.3 µg/m³, 0.5× usual Florence Florence, 10 March: 2.2 µg/m³, 0.3× usual Florence, 11 March: 11.1 µg/m³, 1.3× usual Florence, 12 March: 23.1 µg/m³, 2.7× usual Florence, 13 March: 21.1 µg/m³, 2.5× usual Florence, 14 March: 35.2 µg/m³, 4.1× usual Florence, 15 March: 22.8 µg/m³, 2.7× usual Florence, 16 March: 12.9 µg/m³, 1.5× usual Florence, 17 March: 7.8 µg/m³, 0.9× usual Florence, 18 March: 5.6 µg/m³, 0.7× usual Gainesville Gainesville, 10 March: 2.8 µg/m³, 0.3× usual Gainesville, 11 March: 3.1 µg/m³, 0.3× usual Gainesville, 12 March: 9.0 µg/m³, 1.0× usual Gainesville, 13 March: 22.9 µg/m³, 2.5× usual Gainesville, 14 March: 35.0 µg/m³, 3.9× usual Gainesville, 15 March: 20.2 µg/m³, 2.2× usual Gainesville, 16 March: 5.8 µg/m³, 0.6× usual Gainesville, 17 March: 6.3 µg/m³, 0.7× usual Gainesville, 18 March: 4.1 µg/m³, 0.5× usual Forest Park Forest Park, 10 March: 3.0 µg/m³, 0.4× usual Forest Park, 11 March: 3.2 µg/m³, 0.5× usual Forest Park, 12 March: 14.2 µg/m³, 2.1× usual Forest Park, 13 March: 24.4 µg/m³, 3.6× usual Forest Park, 14 March: 33.0 µg/m³, 4.9× usual Forest Park, 15 March: 17.5 µg/m³, 2.6× usual Forest Park, 16 March: 5.4 µg/m³, 0.8× usual Forest Park, 17 March: 6.0 µg/m³, 0.9× usual Forest Park, 18 March: 4.5 µg/m³, 0.7× usual Valdosta Valdosta, 10 March: 4.0 µg/m³, 0.4× usual Valdosta, 11 March: 3.2 µg/m³, 0.4× usual Valdosta, 12 March: 20.4 µg/m³, 2.3× usual Valdosta, 13 March: 21.9 µg/m³, 2.4× usual Valdosta, 14 March: 30.7 µg/m³, 3.4× usual Valdosta, 15 March: 22.9 µg/m³, 2.5× usual Valdosta, 16 March: 6.5 µg/m³, 0.7× usual Valdosta, 17 March: 7.6 µg/m³, 0.8× usual Valdosta, 18 March: 7.2 µg/m³, 0.8× usual Greenville Greenville, 10 March: 2.2 µg/m³, 0.2× usual Greenville, 11 March: 3.4 µg/m³, 0.4× usual Greenville, 12 March: 8.9 µg/m³, 1.0× usual Greenville, 13 March: 14.9 µg/m³, 1.6× usual Greenville, 14 March: 29.8 µg/m³, 3.3× usual Greenville, 15 March: 36.6 µg/m³, 4.0× usual Greenville, 16 March: 4.8 µg/m³, 0.5× usual Greenville, 17 March: 5.0 µg/m³, 0.5× usual Greenville, 18 March: 3.6 µg/m³, 0.4× usual Conway Conway, 10 March: 2.5 µg/m³, 0.4× usual Conway, 11 March: 5.1 µg/m³, 0.7× usual Conway, 12 March: 8.2 µg/m³, 1.2× usual Conway, 13 March: 16.9 µg/m³, 2.4× usual Conway, 14 March: 28.9 µg/m³, 4.1× usual Conway, 15 March: 22.0 µg/m³, 3.1× usual Conway, 16 March: 12.6 µg/m³, 1.8× usual Conway, 17 March: 7.6 µg/m³, 1.1× usual Conway, 18 March: 5.1 µg/m³, 0.7× usual Spartanburg Spartanburg, 10 March: 2.0 µg/m³, 0.2× usual Spartanburg, 11 March: 2.7 µg/m³, 0.3× usual Spartanburg, 12 March: 8.0 µg/m³, 0.8× usual Spartanburg, 13 March: 13.0 µg/m³, 1.4× usual Spartanburg, 14 March: 28.5 µg/m³, 3.0× usual Spartanburg, 15 March: 34.8 µg/m³, 3.6× usual Spartanburg, 16 March: 7.5 µg/m³, 0.8× usual Spartanburg, 17 March: 5.4 µg/m³, 0.6× usual Spartanburg, 18 March: 4.7 µg/m³, 0.5× usual Savannah Savannah, 10 March: 2.8 µg/m³, 0.3× usual Savannah, 11 March: 3.9 µg/m³, 0.5× usual Savannah, 12 March: 13.0 µg/m³, 1.6× usual Savannah, 13 March: 16.1 µg/m³, 2.0× usual Savannah, 14 March: 28.5 µg/m³, 3.5× usual Savannah, 15 March: 23.2 µg/m³, 2.9× usual Savannah, 16 March: 5.8 µg/m³, 0.7× usual Savannah, 17 March: 5.7 µg/m³, 0.7× usual Savannah, 18 March: 6.2 µg/m³, 0.8× usual Knoxville Knoxville, 10 March: 3.0 µg/m³, 0.4× usual Knoxville, 11 March: 3.8 µg/m³, 0.5× usual Knoxville, 12 March: 11.2 µg/m³, 1.4× usual Knoxville, 13 March: 17.1 µg/m³, 2.1× usual Knoxville, 14 March: 26.9 µg/m³, 3.3× usual Knoxville, 15 March: 11.4 µg/m³, 1.4× usual Knoxville, 16 March: 3.1 µg/m³, 0.4× usual Knoxville, 17 March: 5.0 µg/m³, 0.6× usual Knoxville, 18 March: 3.0 µg/m³, 0.4× usual Kennesaw Kennesaw, 10 March: 3.1 µg/m³, 0.4× usual Kennesaw, 11 March: 4.9 µg/m³, 0.7× usual Kennesaw, 12 March: 18.5 µg/m³, 2.6× usual Kennesaw, 13 March: 24.4 µg/m³, 3.4× usual Kennesaw, 14 March: 26.3 µg/m³, 3.7× usual Kennesaw, 15 March: 15.5 µg/m³, 2.2× usual Kennesaw, 16 March: 6.1 µg/m³, 0.8× usual Kennesaw, 17 March: 7.0 µg/m³, 1.0× usual Kennesaw, 18 March: 5.2 µg/m³, 0.7× usual Lawrenceville Lawrenceville, 10 March: 2.4 µg/m³, 0.3× usual Lawrenceville, 11 March: 2.4 µg/m³, 0.3× usual Lawrenceville, 12 March: 9.6 µg/m³, 1.1× usual Lawrenceville, 13 March: 17.3 µg/m³, 2.0× usual Lawrenceville, 14 March: 26.0 µg/m³, 3.0× usual Lawrenceville, 15 March: 17.4 µg/m³, 2.0× usual Lawrenceville, 16 March: 4.5 µg/m³, 0.5× usual Lawrenceville, 17 March: 5.6 µg/m³, 0.7× usual Lawrenceville, 18 March: 3.9 µg/m³, 0.5× usual Winston-Salem Winston-Salem, 10 March: 2.0 µg/m³, 0.3× usual Winston-Salem, 11 March: 1.9 µg/m³, 0.3× usual Winston-Salem, 12 March: 4.2 µg/m³, 0.6× usual Winston-Salem, 13 March: 8.8 µg/m³, 1.2× usual Winston-Salem, 14 March: 19.0 µg/m³, 2.6× usual Winston-Salem, 15 March: 40.1 µg/m³, 5.5× usual Winston-Salem, 16 March: 9.4 µg/m³, 1.3× usual Winston-Salem, 17 March: 5.1 µg/m³, 0.7× usual Winston-Salem, 18 March: 3.1 µg/m³, 0.4× usual Clemmons Clemmons, 10 March: 1.9 µg/m³, 0.3× usual Clemmons, 11 March: 1.7 µg/m³, 0.2× usual Clemmons, 12 March: 3.6 µg/m³, 0.5× usual Clemmons, 13 March: 7.9 µg/m³, 1.1× usual Clemmons, 14 March: 16.8 µg/m³, 2.4× usual Clemmons, 15 March: 37.7 µg/m³, 5.3× usual Clemmons, 16 March: 10.2 µg/m³, 1.4× usual Clemmons, 17 March: 5.5 µg/m³, 0.8× usual Clemmons, 18 March: 2.9 µg/m³, 0.4× usual Hickory Hickory, 10 March: 2.4 µg/m³, 0.3× usual Hickory, 11 March: 3.6 µg/m³, 0.5× usual Hickory, 12 March: 9.0 µg/m³, 1.2× usual Hickory, 13 March: 14.5 µg/m³, 1.9× usual Hickory, 14 March: 20.5 µg/m³, 2.6× usual Hickory, 15 March: 32.9 µg/m³, 4.2× usual Hickory, 16 March: 5.6 µg/m³, 0.7× usual Hickory, 17 March: 4.5 µg/m³, 0.6× usual Hickory, 18 March: 3.7 µg/m³, 0.5× usual Morrisville Morrisville, 10 March: 2.8 µg/m³, 0.4× usual Morrisville, 11 March: 3.1 µg/m³, 0.4× usual Morrisville, 12 March: 4.6 µg/m³, 0.6× usual Morrisville, 13 March: 9.4 µg/m³, 1.3× usual Morrisville, 14 March: 16.6 µg/m³, 2.3× usual Morrisville, 15 March: 30.5 µg/m³, 4.2× usual Morrisville, 16 March: 11.7 µg/m³, 1.6× usual Morrisville, 17 March: 9.1 µg/m³, 1.2× usual Morrisville, 18 March: 4.1 µg/m³, 0.6× usual Charlotte Charlotte, 10 March: 2.2 µg/m³, 0.3× usual Charlotte, 11 March: 3.6 µg/m³, 0.4× usual Charlotte, 12 March: 7.9 µg/m³, 0.9× usual Charlotte, 13 March: 12.7 µg/m³, 1.5× usual Charlotte, 14 March: 18.5 µg/m³, 2.2× usual Charlotte, 15 March: 30.0 µg/m³, 3.5× usual Charlotte, 16 March: 11.0 µg/m³, 1.3× usual Charlotte, 17 March: 5.9 µg/m³, 0.7× usual Charlotte, 18 March: 3.9 µg/m³, 0.5× usual Lexington Lexington, 10 March: 1.4 µg/m³, 0.2× usual Lexington, 11 March: 1.9 µg/m³, 0.2× usual Lexington, 12 March: 7.0 µg/m³, 0.8× usual Lexington, 13 March: 10.0 µg/m³, 1.2× usual Lexington, 14 March: 14.6 µg/m³, 1.7× usual Lexington, 15 March: 29.8 µg/m³, 3.5× usual Lexington, 16 March: 9.4 µg/m³, 1.1× usual Lexington, 17 March: 5.7 µg/m³, 0.7× usual Lexington, 18 March: 3.0 µg/m³, 0.4× usual Durham Durham, 10 March: 6.5 µg/m³, 0.9× usual Durham, 11 March: 8.7 µg/m³, 1.1× usual Durham, 12 March: 10.9 µg/m³, 1.4× usual Durham, 13 March: 13.1 µg/m³, 1.7× usual Durham, 14 March: 20.1 µg/m³, 2.6× usual Durham, 15 March: 29.3 µg/m³, 3.9× usual Durham, 16 March: 12.2 µg/m³, 1.6× usual Durham, 17 March: 10.1 µg/m³, 1.3× usual Durham, 18 March: 8.3 µg/m³, 1.1× usual Raleigh Raleigh, 10 March: 2.3 µg/m³, 0.3× usual Raleigh, 11 March: 2.0 µg/m³, 0.3× usual Raleigh, 12 March: 4.9 µg/m³, 0.7× usual Raleigh, 13 March: 11.5 µg/m³, 1.6× usual Raleigh, 14 March: 17.8 µg/m³, 2.5× usual Raleigh, 15 March: 29.1 µg/m³, 4.0× usual Raleigh, 16 March: 11.1 µg/m³, 1.5× usual Raleigh, 17 March: 8.5 µg/m³, 1.2× usual Raleigh, 18 March: 3.6 µg/m³, 0.5× usual Greensboro Greensboro, 10 March: 2.5 µg/m³, 0.3× usual Greensboro, 11 March: 2.7 µg/m³, 0.4× usual Greensboro, 12 March: 5.2 µg/m³, 0.7× usual Greensboro, 13 March: 7.0 µg/m³, 1.0× usual Greensboro, 14 March: 14.3 µg/m³, 2.0× usual Greensboro, 15 March: 28.9 µg/m³, 4.0× usual Greensboro, 16 March: 9.0 µg/m³, 1.3× usual Greensboro, 17 March: 5.8 µg/m³, 0.8× usual Greensboro, 18 March: 2.9 µg/m³, 0.4× usual East Hampton East Hampton, 10 March: 2.2 µg/m³, 0.4× usual East Hampton, 11 March: 1.6 µg/m³, 0.3× usual East Hampton, 12 March: 3.0 µg/m³, 0.5× usual East Hampton, 13 March: 6.8 µg/m³, 1.1× usual East Hampton, 14 March: 11.2 µg/m³, 1.9× usual East Hampton, 15 March: 27.8 µg/m³, 4.6× usual East Hampton, 16 March: 5.2 µg/m³, 0.9× usual East Hampton, 17 March: 6.5 µg/m³, 1.1× usual East Hampton, 18 March: 3.5 µg/m³, 0.6× usual Roanoke Rapids Roanoke Rapids, 10 March: 1.9 µg/m³, 0.3× usual Roanoke Rapids, 11 March: 1.6 µg/m³, 0.3× usual Roanoke Rapids, 12 March: 2.8 µg/m³, 0.5× usual Roanoke Rapids, 13 March: 7.2 µg/m³, 1.3× usual Roanoke Rapids, 14 March: 13.1 µg/m³, 2.3× usual Roanoke Rapids, 15 March: 25.9 µg/m³, 4.5× usual Roanoke Rapids, 16 March: 8.2 µg/m³, 1.4× usual Roanoke Rapids, 17 March: 8.1 µg/m³, 1.4× usual Roanoke Rapids, 18 March: 3.7 µg/m³, 0.6× usual Chesapeake Chesapeake, 10 March: 1.9 µg/m³, 0.3× usual Chesapeake, 11 March: 1.7 µg/m³, 0.3× usual Chesapeake, 12 March: 4.2 µg/m³, 0.7× usual Chesapeake, 13 March: 7.4 µg/m³, 1.2× usual Chesapeake, 14 March: 12.3 µg/m³, 2.0× usual Chesapeake, 15 March: 25.1 µg/m³, 4.0× usual Chesapeake, 16 March: 6.1 µg/m³, 1.0× usual Chesapeake, 17 March: 5.7 µg/m³, 0.9× usual Chesapeake, 18 March: 3.9 µg/m³, 0.6× usual 10 Mar 11 12 13 14 15 16 17 18 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
Saint Andrews South Carolina, United States 2 14 March 7.8 6.8× Winston-Salem North Carolina, United States 1 15 March 7.3 5.5× Clemmons North Carolina, United States 1 15 March 7.1 5.3× Forest Park Georgia, United States 1 14 March 6.7 4.9× Athens Georgia, United States 2 14 March 8.5 4.9× East Hampton Virginia, United States 1 15 March 6.0 4.6× Roanoke Rapids North Carolina, United States 1 15 March 5.7 4.5× Columbus Georgia, United States 2 13 March 10.4 4.2× Hickory North Carolina, United States 1 15 March 7.8 4.2× Morrisville North Carolina, United States 1 15 March 7.3 4.2× Florence South Carolina, United States 1 14 March 8.6 4.1× Warner Robins Georgia, United States 2 14 March 9.2 4.1× Conway South Carolina, United States 1 14 March 7.1 4.1× Chesapeake Virginia, United States 1 15 March 6.2 4.0× Raleigh North Carolina, United States 1 15 March 7.2 4.0× Greenville South Carolina, United States 2 15 March 9.1 4.0× Greensboro North Carolina, United States 1 15 March 7.2 4.0× Phenix City Alabama, United States 2 14 March 9.2 3.9× Gainesville Georgia, United States 1 14 March 9.0 3.9× Durham North Carolina, United States 1 15 March 7.6 3.9× Kennesaw Georgia, United States 1 14 March 7.2 3.7× Spartanburg South Carolina, United States 2 15 March 9.6 3.6× Macon Georgia, United States 3 14 March 10.3 3.6× Lexington North Carolina, United States 1 15 March 8.4 3.5× Charlotte North Carolina, United States 1 15 March 8.5 3.5× Savannah Georgia, United States 1 14 March 8.1 3.5× Augusta Georgia, United States 2 14 March 9.6 3.5× Valdosta Georgia, United States 1 14 March 9.0 3.4× Knoxville Tennessee, United States 1 14 March 8.1 3.3× Albany Georgia, United States 3 13 March 11.1 3.1× Trussville Alabama, United States 1 13 March 9.0 3.0× Lawrenceville Georgia, United States 1 14 March 8.6 3.0×
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 29 of 131 episodes in the United States since our records began, by cities reached.
North-eastern United States and Canada, June and July 2023 280 North-eastern United States and Canada, July 2026 264 North-eastern United States and Canada, May and June 2023 261 North-eastern United States and Canada, July and August 2025 241 North-eastern United States and Canada, July 2023 240 North-eastern United States and Canada, June 2025 196 North-eastern United States and Canada, June 2023 161 North-eastern United States and Canada, July 2025 119 North-western United States and Canada, August 2023 110 North-eastern United States, June 2025 104 North-western United States and Canada, August 2026 99 North-eastern United States and Canada, February 2026 96 Eastern United States, March 2024 32 Bars: cities reached; colour: the level of the episode's highest daily reading. All 131 .
Use this page SmogRank, Eastern United States, March 2024: 32 cities with PM2.5 at twice their usual or more, 13 to 15 March 2024, smogrank.com/episodes/2024-03-eastern-united-states (accessed 3 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.
