SmogRank / Episodes / United States
North-eastern United States, February 2024
For 1 day, on 22 February 2024, 12 cities in the United States and Canada had PM2.5 at least twice their usual for the time of year. The worst reading was Dearborn, Michigan, United States: 38.1 µg/m³ on 22 February, about 4.1× its usual 9.2.
No cause named We have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached 12 in 2 countries
Days 1 22 February 2024
Worst day 22 February 12 cities counted
Furthest above usual 4.8× Jenison
Day by day
Play 22 February 12 cities at twice their usual or more
Fort Wayne Elkhart South Bend Muncie Kokomo Lima Anderson Fishers Wyoming Holland Ypsilanti Lafayette Dayton Portage Springfield Middletown Gary Lebanon Redford Mason White Oak Flint Columbus Hammond Calumet City Norwood Cincinnati Fort Thomas Chicago Dublin Eastpointe Oak Lawn Bloomington Bay City Westerville Columbus Brookfield Franklin Park Northbrook Gahanna Des Plaines Zion Joliet Terre Haute Naperville South Milwaukee Cary Milwaukee Chatham Port Huron Sarnia Medina Waukesha Cleveland Cleveland Heights Shaker Heights Akron Bloomington Canton Rockford Painesville Decatur St. Thomas London Peoria Warren Madison Youngstown Springfield Wheeling Steubenville Weirton Hermitage Weirton Heights Clinton Kitchener Erie Brantford Moline Pittsburgh Davenport Wilkinsburg Guelph West Mifflin McKeesport Upper Alton Waterdown Hamilton Milton Indianapolis Toledo Lincoln Park Windsor Taylor Detroit East Chicago Grand Rapids Dearborn Lansing Kalamazoo Jenison 19 Feb 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
Dearborn Dearborn, 19 February: 8.6 µg/m³, 0.9× usual Dearborn, 20 February: 17.6 µg/m³, 1.9× usual Dearborn, 21 February: 24.4 µg/m³, 2.7× usual Dearborn, 22 February: 38.1 µg/m³, 4.1× usual Dearborn, 23 February: 20.3 µg/m³, 2.2× usual Dearborn, 24 February: 6.1 µg/m³, 0.7× usual Dearborn, 25 February: 15.7 µg/m³, 1.7× usual Kalamazoo Kalamazoo, 19 February: 14.9 µg/m³, 1.8× usual Kalamazoo, 20 February: 19.2 µg/m³, 2.4× usual Kalamazoo, 21 February: 21.8 µg/m³, 2.7× usual Kalamazoo, 22 February: 35.3 µg/m³, 4.4× usual Kalamazoo, 23 February: 12.7 µg/m³, 1.6× usual Kalamazoo, 24 February: 3.3 µg/m³, 0.4× usual Kalamazoo, 25 February: 12.8 µg/m³, 1.6× usual Detroit Detroit, 19 February: 8.0 µg/m³, 0.9× usual Detroit, 20 February: 14.4 µg/m³, 1.5× usual Detroit, 21 February: 18.8 µg/m³, 2.0× usual Detroit, 22 February: 32.3 µg/m³, 3.5× usual Detroit, 23 February: 16.8 µg/m³, 1.8× usual Detroit, 24 February: 3.3 µg/m³, 0.4× usual Detroit, 25 February: 8.7 µg/m³, 0.9× usual Jenison Jenison, 19 February: 14.8 µg/m³, 2.3× usual Jenison, 20 February: 16.8 µg/m³, 2.6× usual Jenison, 21 February: 21.2 µg/m³, 3.3× usual Jenison, 22 February: 30.9 µg/m³, 4.8× usual Jenison, 23 February: 10.7 µg/m³, 1.6× usual Jenison, 24 February: 3.4 µg/m³, 0.5× usual Jenison, 25 February: 10.4 µg/m³, 1.6× usual Windsor Windsor, 19 February: 8.0 µg/m³, 0.9× usual Windsor, 20 February: 15.0 µg/m³, 1.7× usual Windsor, 21 February: 16.9 µg/m³, 1.9× usual Windsor, 22 February: 30.6 µg/m³, 3.4× usual Windsor, 23 February: 15.7 µg/m³, 1.7× usual Windsor, 24 February: 3.7 µg/m³, 0.4× usual Windsor, 25 February: 10.9 µg/m³, 1.2× usual East Chicago East Chicago, 19 February: 9.3 µg/m³, 1.2× usual East Chicago, 20 February: 17.4 µg/m³, 2.2× usual East Chicago, 21 February: 22.0 µg/m³, 2.8× usual East Chicago, 22 February: 30.4 µg/m³, 3.8× usual East Chicago, 23 February: 10.5 µg/m³, 1.3× usual East Chicago, 24 February: 4.8 µg/m³, 0.6× usual East Chicago, 25 February: 11.1 µg/m³, 1.4× usual Grand Rapids Grand Rapids, 19 February: 15.1 µg/m³, 2.0× usual Grand Rapids, 20 February: 18.5 µg/m³, 2.5× usual Grand Rapids, 21 February: 24.7 µg/m³, 3.3× usual Grand Rapids, 22 February: 29.6 µg/m³, 3.9× usual Grand Rapids, 23 February: 13.3 µg/m³, 1.8× usual Grand Rapids, 24 February: 4.4 µg/m³, 0.6× usual Grand Rapids, 25 February: 12.5 µg/m³, 1.7× usual Lincoln Park Lincoln Park, 19 February: 7.4 µg/m³, 0.8× usual Lincoln Park, 20 February: 13.1 µg/m³, 1.4× usual Lincoln Park, 21 February: 15.8 µg/m³, 1.6× usual Lincoln Park, 22 February: 28.6 µg/m³, 3.0× usual Lincoln Park, 23 February: 15.7 µg/m³, 1.6× usual Lincoln Park, 24 February: 3.9 µg/m³, 0.4× usual Lincoln Park, 25 February: 9.1 µg/m³, 0.9× usual Lansing Lansing, 19 February: 9.7 µg/m³, 1.5× usual Lansing, 20 February: 15.2 µg/m³, 2.3× usual Lansing, 21 February: 17.5 µg/m³, 2.7× usual Lansing, 22 February: 27.5 µg/m³, 4.2× usual Lansing, 23 February: 10.1 µg/m³, 1.5× usual Lansing, 24 February: 2.6 µg/m³, 0.4× usual Lansing, 25 February: 7.3 µg/m³, 1.1× usual Taylor Taylor, 19 February: 6.9 µg/m³, 0.9× usual Taylor, 20 February: 11.3 µg/m³, 1.5× usual Taylor, 21 February: 14.1 µg/m³, 1.9× usual Taylor, 22 February: 26.0 µg/m³, 3.5× usual Taylor, 23 February: 12.6 µg/m³, 1.7× usual Taylor, 24 February: 3.0 µg/m³, 0.4× usual Taylor, 25 February: 7.3 µg/m³, 1.0× usual Toledo Toledo, 19 February: 15.1 µg/m³, 1.7× usual Toledo, 20 February: 19.2 µg/m³, 2.2× usual Toledo, 21 February: 14.9 µg/m³, 1.7× usual Toledo, 22 February: 25.2 µg/m³, 2.9× usual Toledo, 23 February: 12.9 µg/m³, 1.5× usual Toledo, 24 February: 4.0 µg/m³, 0.5× usual Toledo, 25 February: 10.0 µg/m³, 1.1× usual Indianapolis Indianapolis, 19 February: 13.2 µg/m³, 1.5× usual Indianapolis, 20 February: 18.3 µg/m³, 2.0× usual Indianapolis, 21 February: 21.5 µg/m³, 2.4× usual Indianapolis, 22 February: 25.2 µg/m³, 2.8× usual Indianapolis, 23 February: 14.6 µg/m³, 1.6× usual Indianapolis, 24 February: 6.5 µg/m³, 0.7× usual Indianapolis, 25 February: 9.6 µg/m³, 1.1× usual 19 Feb 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
Jenison Michigan, United States 1 22 February 6.5 4.8× Kalamazoo Michigan, United States 1 22 February 8.1 4.4× Lansing Michigan, United States 1 22 February 6.6 4.2× Dearborn Michigan, United States 1 22 February 9.2 4.1× Grand Rapids Michigan, United States 1 22 February 7.5 3.9× East Chicago Indiana, United States 1 22 February 7.9 3.8× Taylor Michigan, United States 1 22 February 7.4 3.5× Detroit Michigan, United States 1 22 February 9.3 3.5× Windsor Ontario, Canada 1 22 February 9.0 3.4× Lincoln Park Michigan, United States 1 22 February 9.6 3.0× Toledo Ohio, United States 1 22 February 8.8 2.9× Indianapolis Indiana, United States 1 22 February 9.1 2.8×
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 and Canada
Number 91 of 142 episodes in the United States and Canada 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 North-eastern United States, February 2024 12 Bars: cities reached; colour: the level of the episode's highest daily reading. All 142 .
Use this page SmogRank, North-eastern United States, February 2024: 12 cities with PM2.5 at twice their usual or more, 22 February 2024, smogrank.com/episodes/2024-02-north-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.
