SmogRank / Episodes / United States
Southern United States and Mexico, April 2026
For 4 days, from 25 to 28 April 2026, 21 cities in the United States and Mexico had PM2.5 at least twice their usual for the time of year. The worst reading was Piedras Negras, Coahuila, Mexico: 986.0 µg/m³ on 26 April, about 2.8× its usual 353.0.
No cause named We have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached 21 in 2 countries
Days 4 25 to 28 April 2026
Worst day 27 April 15 cities counted
Furthest above usual 3.9× Pflugerville
Day by day
Play 27 April 15 cities at twice their usual or more
College Station Mission Bend Missouri City Houston Conroe Pasadena Deer Park La Porte Baytown Galveston Corsicana Sulphur Shreveport Cadereyta Jiménez Ciudad Benito Juárez Ciudad General Escobedo Monterrey Parque Industrial Ciudad Mitras García Santa Catarina Texarkana Saltillo Lubbock Brownsville Ciudad Apodaca Mission Edinburg Corpus Christi Piedras Negras Dallas Saginaw Fort Worth Live Oak Port Arthur Eagle Pass San Antonio Laredo Austin Denton Taylor Belton San Marcos Pflugerville Cedar Park 22 Apr 23 24 25 26 27 28 29 30 1 May 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
Port Arthur Port Arthur, 22 April: 27.5 µg/m³, 3.3× usual Port Arthur, 23 April: 25.4 µg/m³, 3.0× usual Port Arthur, 24 April: 25.8 µg/m³, 3.1× usual Port Arthur, 25 April: 21.3 µg/m³, 2.5× usual Port Arthur, 26 April: 22.1 µg/m³, 2.6× usual Port Arthur, 27 April: 27.1 µg/m³, 3.2× usual Port Arthur, 28 April: 28.0 µg/m³, 3.3× usual Port Arthur, 29 April: 27.8 µg/m³, 3.3× usual Port Arthur, 30 April: 20.7 µg/m³, 2.5× usual Port Arthur, 1 May: 11.3 µg/m³, 1.3× usual Laredo Laredo, 22 April: 10.7 µg/m³, 0.9× usual Laredo, 23 April: 15.0 µg/m³, 1.3× usual Laredo, 24 April: 27.0 µg/m³, 2.3× usual Laredo, 25 April: 32.7 µg/m³, 2.8× usual Laredo, 26 April: 31.6 µg/m³, 2.7× usual Laredo, 27 April: 34.3 µg/m³, 3.0× usual Laredo, 28 April: 39.2 µg/m³, 3.4× usual Laredo, 29 April: 29.8 µg/m³, 2.6× usual Laredo, 30 April: 16.5 µg/m³, 1.4× usual Laredo, 1 May: 5.9 µg/m³, 0.5× usual San Antonio San Antonio, 22 April: 8.7 µg/m³, 1.0× usual San Antonio, 23 April: 9.0 µg/m³, 1.0× usual San Antonio, 24 April: 16.5 µg/m³, 1.9× usual San Antonio, 25 April: 30.2 µg/m³, 3.4× usual San Antonio, 26 April: 26.7 µg/m³, 3.0× usual San Antonio, 27 April: 30.7 µg/m³, 3.4× usual San Antonio, 28 April: 28.8 µg/m³, 3.2× usual San Antonio, 29 April: 23.1 µg/m³, 2.6× usual San Antonio, 30 April: 6.2 µg/m³, 0.7× usual San Antonio, 1 May: 1.6 µg/m³, 0.2× usual Eagle Pass Eagle Pass, 22 April: 8.8 µg/m³, 0.9× usual Eagle Pass, 23 April: 13.2 µg/m³, 1.3× usual Eagle Pass, 24 April: 18.3 µg/m³, 1.8× usual Eagle Pass, 25 April: 28.0 µg/m³, 2.8× usual Eagle Pass, 26 April: 31.9 µg/m³, 3.2× usual Eagle Pass, 27 April: 28.5 µg/m³, 2.8× usual Eagle Pass, 28 April: 33.9 µg/m³, 3.4× usual Eagle Pass, 29 April: 30.5 µg/m³, 3.0× usual Eagle Pass, 30 April: 12.7 µg/m³, 1.3× usual Eagle Pass, 1 May: 4.3 µg/m³, 0.4× usual Austin Austin, 22 April: 9.2 µg/m³, 1.0× usual Austin, 23 April: 10.3 µg/m³, 1.1× usual Austin, 24 April: 16.5 µg/m³, 1.8× usual Austin, 25 April: 27.8 µg/m³, 3.0× usual Austin, 26 April: 29.1 µg/m³, 3.1× usual Austin, 27 April: 31.7 µg/m³, 3.4× usual Austin, 28 April: 31.2 µg/m³, 3.4× usual Austin, 29 April: 16.9 µg/m³, 1.8× usual Austin, 30 April: 7.4 µg/m³, 0.8× usual Austin, 1 May: 4.1 µg/m³, 0.4× usual Live Oak Live Oak, 22 April: 7.3 µg/m³, 0.8× usual Live Oak, 23 April: 8.8 µg/m³, 1.0× usual Live Oak, 24 April: 15.1 µg/m³, 1.7× usual Live Oak, 25 April: 27.1 µg/m³, 3.0× usual Live Oak, 26 April: 24.7 µg/m³, 2.7× usual Live Oak, 27 April: 28.2 µg/m³, 3.1× usual Live Oak, 28 April: 27.4 µg/m³, 3.0× usual Live Oak, 29 April: 21.3 µg/m³, 2.3× usual Live Oak, 30 April: 5.5 µg/m³, 0.6× usual Live Oak, 1 May: 1.9 µg/m³, 0.2× usual Edinburg Edinburg, 22 April: 7.7 µg/m³, 0.6× usual Edinburg, 23 April: 11.4 µg/m³, 0.9× usual Edinburg, 24 April: 24.2 µg/m³, 1.9× usual Edinburg, 25 April: 26.5 µg/m³, 2.1× usual Edinburg, 26 April: 21.6 µg/m³, 1.7× usual Edinburg, 27 April: 25.5 µg/m³, 2.0× usual Edinburg, 28 April: 29.1 µg/m³, 2.3× usual Edinburg, 29 April: 16.6 µg/m³, 1.3× usual Edinburg, 30 April: 17.6 µg/m³, 1.4× usual Edinburg, 1 May: 7.7 µg/m³, 0.6× usual Mission Mission, 22 April: 8.1 µg/m³, 0.6× usual Mission, 23 April: 12.3 µg/m³, 0.9× usual Mission, 24 April: 22.6 µg/m³, 1.6× usual Mission, 25 April: 25.9 µg/m³, 1.8× usual Mission, 26 April: 23.7 µg/m³, 1.6× usual Mission, 27 April: 24.9 µg/m³, 1.7× usual Mission, 28 April: 30.9 µg/m³, 2.1× usual Mission, 29 April: 19.0 µg/m³, 1.3× usual Mission, 30 April: 21.4 µg/m³, 1.5× usual Mission, 1 May: 8.2 µg/m³, 0.6× usual Piedras Negras Piedras Negras, 22 April: no reading Piedras Negras, 23 April: no reading Piedras Negras, 24 April: no reading Piedras Negras, 25 April: no reading Piedras Negras, 26 April: 986.0 µg/m³, 2.8× usual Piedras Negras, 27 April: no reading Piedras Negras, 28 April: no reading Piedras Negras, 29 April: 986.0 µg/m³, 2.8× usual Piedras Negras, 30 April: no reading Piedras Negras, 1 May: 986.0 µg/m³, 2.8× usual San Marcos San Marcos, 22 April: 7.3 µg/m³, 0.9× usual San Marcos, 23 April: 7.6 µg/m³, 1.0× usual San Marcos, 24 April: 13.7 µg/m³, 1.8× usual San Marcos, 25 April: 23.7 µg/m³, 3.0× usual San Marcos, 26 April: 23.7 µg/m³, 3.0× usual San Marcos, 27 April: 30.1 µg/m³, 3.9× usual San Marcos, 28 April: 24.2 µg/m³, 3.1× usual San Marcos, 29 April: 18.0 µg/m³, 2.3× usual San Marcos, 30 April: 5.0 µg/m³, 0.6× usual San Marcos, 1 May: 2.3 µg/m³, 0.3× usual Corpus Christi Corpus Christi, 22 April: 11.7 µg/m³, 1.0× usual Corpus Christi, 23 April: 10.9 µg/m³, 0.9× usual Corpus Christi, 24 April: 16.8 µg/m³, 1.5× usual Corpus Christi, 25 April: 20.7 µg/m³, 1.8× usual Corpus Christi, 26 April: 22.3 µg/m³, 1.9× usual Corpus Christi, 27 April: 27.3 µg/m³, 2.4× usual Corpus Christi, 28 April: 24.4 µg/m³, 2.1× usual Corpus Christi, 29 April: 17.0 µg/m³, 1.5× usual Corpus Christi, 30 April: 14.9 µg/m³, 1.3× usual Corpus Christi, 1 May: 6.7 µg/m³, 0.6× usual Cedar Park Cedar Park, 22 April: 5.0 µg/m³, 0.7× usual Cedar Park, 23 April: 7.1 µg/m³, 1.0× usual Cedar Park, 24 April: 13.5 µg/m³, 1.8× usual Cedar Park, 25 April: 22.5 µg/m³, 3.0× usual Cedar Park, 26 April: 24.5 µg/m³, 3.3× usual Cedar Park, 27 April: 27.0 µg/m³, 3.6× usual Cedar Park, 28 April: 28.5 µg/m³, 3.9× usual Cedar Park, 29 April: 10.3 µg/m³, 1.4× usual Cedar Park, 30 April: 5.0 µg/m³, 0.7× usual Cedar Park, 1 May: 1.4 µg/m³, 0.2× usual Taylor Taylor, 22 April: 7.0 µg/m³, 0.9× usual Taylor, 23 April: 6.9 µg/m³, 0.9× usual Taylor, 24 April: 13.5 µg/m³, 1.8× usual Taylor, 25 April: 22.9 µg/m³, 3.1× usual Taylor, 26 April: 23.0 µg/m³, 3.1× usual Taylor, 27 April: 26.7 µg/m³, 3.6× usual Taylor, 28 April: 21.0 µg/m³, 2.8× usual Taylor, 29 April: 10.5 µg/m³, 1.4× usual Taylor, 30 April: 4.2 µg/m³, 0.6× usual Taylor, 1 May: 3.2 µg/m³, 0.4× usual Belton Belton, 22 April: 7.4 µg/m³, 1.0× usual Belton, 23 April: 6.1 µg/m³, 0.8× usual Belton, 24 April: 13.4 µg/m³, 1.9× usual Belton, 25 April: 22.6 µg/m³, 3.1× usual Belton, 26 April: 23.3 µg/m³, 3.2× usual Belton, 27 April: 26.4 µg/m³, 3.7× usual Belton, 28 April: 27.0 µg/m³, 3.8× usual Belton, 29 April: 9.7 µg/m³, 1.3× usual Belton, 30 April: 3.6 µg/m³, 0.5× usual Belton, 1 May: 3.5 µg/m³, 0.5× usual Pflugerville Pflugerville, 22 April: 6.2 µg/m³, 0.9× usual Pflugerville, 23 April: 6.7 µg/m³, 1.0× usual Pflugerville, 24 April: 12.4 µg/m³, 1.9× usual Pflugerville, 25 April: 22.4 µg/m³, 3.3× usual Pflugerville, 26 April: 22.4 µg/m³, 3.3× usual Pflugerville, 27 April: 26.3 µg/m³, 3.9× usual Pflugerville, 28 April: 23.6 µg/m³, 3.5× usual Pflugerville, 29 April: 12.5 µg/m³, 1.9× usual Pflugerville, 30 April: 5.8 µg/m³, 0.9× usual Pflugerville, 1 May: 3.6 µg/m³, 0.5× usual Fort Worth Fort Worth, 22 April: 10.1 µg/m³, 1.2× usual Fort Worth, 23 April: 7.2 µg/m³, 0.9× usual Fort Worth, 24 April: 12.3 µg/m³, 1.5× usual Fort Worth, 25 April: 17.3 µg/m³, 2.1× usual Fort Worth, 26 April: 23.1 µg/m³, 2.8× usual Fort Worth, 27 April: 25.8 µg/m³, 3.1× usual Fort Worth, 28 April: 26.1 µg/m³, 3.1× usual Fort Worth, 29 April: 5.1 µg/m³, 0.6× usual Fort Worth, 30 April: 5.9 µg/m³, 0.7× usual Fort Worth, 1 May: 5.0 µg/m³, 0.6× usual Brownsville Brownsville, 22 April: 8.5 µg/m³, 0.7× usual Brownsville, 23 April: 10.4 µg/m³, 0.8× usual Brownsville, 24 April: 17.3 µg/m³, 1.4× usual Brownsville, 25 April: 19.7 µg/m³, 1.6× usual Brownsville, 26 April: 16.0 µg/m³, 1.3× usual Brownsville, 27 April: 25.3 µg/m³, 2.0× usual Brownsville, 28 April: 21.0 µg/m³, 1.7× usual Brownsville, 29 April: 13.0 µg/m³, 1.0× usual Brownsville, 30 April: 13.0 µg/m³, 1.0× usual Brownsville, 1 May: 10.3 µg/m³, 0.8× usual Ciudad Apodaca Ciudad Apodaca, 22 April: no reading Ciudad Apodaca, 23 April: 16.9 µg/m³, 1.0× usual Ciudad Apodaca, 24 April: 24.0 µg/m³, 1.5× usual Ciudad Apodaca, 25 April: 30.1 µg/m³, 1.9× usual Ciudad Apodaca, 26 April: 27.7 µg/m³, 1.7× usual Ciudad Apodaca, 27 April: 26.3 µg/m³, 1.6× usual Ciudad Apodaca, 28 April: 34.3 µg/m³, 2.1× usual Ciudad Apodaca, 29 April: 27.8 µg/m³, 1.7× usual Ciudad Apodaca, 30 April: 21.5 µg/m³, 1.3× usual Ciudad Apodaca, 1 May: 6.5 µg/m³, 0.4× usual Saginaw Saginaw, 22 April: 7.5 µg/m³, 0.9× usual Saginaw, 23 April: 5.8 µg/m³, 0.7× usual Saginaw, 24 April: 8.3 µg/m³, 1.0× usual Saginaw, 25 April: 16.1 µg/m³, 1.9× usual Saginaw, 26 April: 21.9 µg/m³, 2.6× usual Saginaw, 27 April: 23.5 µg/m³, 2.8× usual Saginaw, 28 April: 25.9 µg/m³, 3.1× usual Saginaw, 29 April: 4.4 µg/m³, 0.5× usual Saginaw, 30 April: no reading Saginaw, 1 May: 4.5 µg/m³, 0.5× usual Denton Denton, 22 April: 11.8 µg/m³, 1.6× usual Denton, 23 April: 6.8 µg/m³, 0.9× usual Denton, 24 April: 9.5 µg/m³, 1.3× usual Denton, 25 April: 13.9 µg/m³, 1.9× usual Denton, 26 April: 21.1 µg/m³, 2.9× usual Denton, 27 April: 21.1 µg/m³, 2.9× usual Denton, 28 April: 25.7 µg/m³, 3.5× usual Denton, 29 April: 4.1 µg/m³, 0.6× usual Denton, 30 April: 5.0 µg/m³, 0.7× usual Denton, 1 May: 4.7 µg/m³, 0.6× usual Dallas Dallas, 22 April: 13.9 µg/m³, 1.6× usual Dallas, 23 April: 9.2 µg/m³, 1.1× usual Dallas, 24 April: no reading Dallas, 25 April: no reading Dallas, 26 April: no reading Dallas, 27 April: no reading Dallas, 28 April: 25.6 µg/m³, 3.0× usual Dallas, 29 April: 8.6 µg/m³, 1.0× usual Dallas, 30 April: 7.6 µg/m³, 0.9× usual Dallas, 1 May: 6.2 µg/m³, 0.7× usual 22 Apr 23 24 25 26 27 28 29 30 1 May 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
Pflugerville Texas, United States 1 27 April 6.7 3.9× San Marcos Texas, United States 1 27 April 7.8 3.9× Cedar Park Texas, United States 2 28 April 7.4 3.9× Belton Texas, United States 2 28 April 7.2 3.8× Taylor Texas, United States 1 27 April 7.4 3.6× Denton Texas, United States 1 28 April 7.3 3.5× San Antonio Texas, United States 4 27 April 8.9 3.4× Laredo Texas, United States 4 28 April 11.5 3.4× Austin Texas, United States 4 27 April 9.3 3.4× Eagle Pass Texas, United States 4 28 April 10.1 3.4× Port Arthur Texas, United States 1 28 April 8.4 3.3× Fort Worth Texas, United States 2 28 April 8.3 3.1× Live Oak Texas, United States 3 27 April 9.1 3.1× Saginaw Texas, United States 1 28 April 8.4 3.1× Dallas Texas, United States 1 28 April 8.6 3.0× Piedras Negras Coahuila, Mexico 1 26 April 353.0 2.8× Corpus Christi Texas, United States 1 27 April 11.5 2.4× Edinburg Texas, United States 3 28 April 12.5 2.3× Mission Texas, United States 2 28 April 14.4 2.1× Ciudad Apodaca Nuevo León, Mexico 1 28 April 16.2 2.1× Brownsville Texas, United States 1 27 April 12.6 2.0×
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 and Mexico
Number 39 of 106 episodes in the United States and Mexico since our records began, by cities reached.
North-eastern United States and Canada, June and July 2023 279 North-eastern United States and Canada, July 2026 264 North-eastern United States and Canada, May and June 2023 260 North-eastern United States and Canada, July and August 2025 241 North-eastern United States and Canada, July 2023 241 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 Southern United States and Mexico, April 2026 21 Bars: cities reached; colour: the level of the episode's highest daily reading. All 106 .
Use this page SmogRank, Southern United States and Mexico, April 2026: 21 cities with PM2.5 at twice their usual or more, 25 to 28 April 2026, smogrank.com/episodes/2026-04-southern-united-states-and-mexico (accessed 2 October 2026).
Copy citation Download top 10 (PNG)
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.
