SmogRank / Episodes / United States
Southern United States and Mexico, May 2024
For 4 days, from 7 to 10 May 2024, 31 cities in the United States and Mexico had PM2.5 at least twice their usual for the time of year. The worst reading was Mission, Texas, United States: 55.4 µg/m³ on 10 May, about 3.9× its usual 14.3.
No cause named We have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached 31 in 2 countries
Days 4 7 to 10 May 2024
Worst day 9 May 26 cities counted
Furthest above usual 5.0× Belton
Day by day
Play 9 May 26 cities at twice their usual or more
Georgetown Fort Worth Shreveport Denton Ciudad Benito Juárez García Saltillo Monterrey Heroica Matamoros Laredo Cadereyta Jiménez Eagle Pass Baton Rouge San Antonio Dallas Saginaw La Porte Texarkana Galveston Baytown Lafayette Edinburg Houston Pasadena College Station Mission Conroe Port Arthur Missouri City Corpus Christi San Marcos Austin Mission Bend Corsicana Live Oak Sulphur Taylor Belton 4 May 5 6 7 8 9 10 11 12 13 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
Laredo Laredo, 4 May: 25.2 µg/m³, 2.0× usual Laredo, 5 May: 15.7 µg/m³, 1.2× usual Laredo, 6 May: 20.4 µg/m³, 1.6× usual Laredo, 7 May: 28.7 µg/m³, 2.3× usual Laredo, 8 May: 29.1 µg/m³, 2.3× usual Laredo, 9 May: no reading Laredo, 10 May: no reading Laredo, 11 May: 20.6 µg/m³, 1.6× usual Laredo, 12 May: 21.1 µg/m³, 1.7× usual Laredo, 13 May: no reading Mission Mission, 4 May: 23.0 µg/m³, 1.6× usual Mission, 5 May: 22.7 µg/m³, 1.6× usual Mission, 6 May: 26.0 µg/m³, 1.8× usual Mission, 7 May: 37.8 µg/m³, 2.6× usual Mission, 8 May: 43.2 µg/m³, 3.0× usual Mission, 9 May: 45.0 µg/m³, 3.1× usual Mission, 10 May: 55.4 µg/m³, 3.9× usual Mission, 11 May: 39.0 µg/m³, 2.7× usual Mission, 12 May: 29.5 µg/m³, 2.1× usual Mission, 13 May: 37.7 µg/m³, 2.6× usual Edinburg Edinburg, 4 May: 17.9 µg/m³, 1.3× usual Edinburg, 5 May: 18.0 µg/m³, 1.3× usual Edinburg, 6 May: 20.1 µg/m³, 1.5× usual Edinburg, 7 May: 31.8 µg/m³, 2.4× usual Edinburg, 8 May: 39.2 µg/m³, 2.9× usual Edinburg, 9 May: 38.2 µg/m³, 2.8× usual Edinburg, 10 May: 48.9 µg/m³, 3.6× usual Edinburg, 11 May: 34.1 µg/m³, 2.5× usual Edinburg, 12 May: 25.2 µg/m³, 1.9× usual Edinburg, 13 May: 33.8 µg/m³, 2.5× usual Corpus Christi Corpus Christi, 4 May: 16.3 µg/m³, 1.3× usual Corpus Christi, 5 May: 16.5 µg/m³, 1.3× usual Corpus Christi, 6 May: 14.5 µg/m³, 1.2× usual Corpus Christi, 7 May: 30.5 µg/m³, 2.5× usual Corpus Christi, 8 May: 43.3 µg/m³, 3.5× usual Corpus Christi, 9 May: 50.1 µg/m³, 4.0× usual Corpus Christi, 10 May: 34.8 µg/m³, 2.8× usual Corpus Christi, 11 May: 17.3 µg/m³, 1.4× usual Corpus Christi, 12 May: 30.5 µg/m³, 2.5× usual Corpus Christi, 13 May: 24.3 µg/m³, 2.0× usual Conroe Conroe, 4 May: 7.8 µg/m³, 0.8× usual Conroe, 5 May: 7.2 µg/m³, 0.7× usual Conroe, 6 May: 15.0 µg/m³, 1.5× usual Conroe, 7 May: 27.4 µg/m³, 2.7× usual Conroe, 8 May: 27.3 µg/m³, 2.7× usual Conroe, 9 May: 40.1 µg/m³, 3.9× usual Conroe, 10 May: 11.4 µg/m³, 1.1× usual Conroe, 11 May: 10.0 µg/m³, 1.0× usual Conroe, 12 May: 7.8 µg/m³, 0.8× usual Conroe, 13 May: 14.7 µg/m³, 1.4× usual Live Oak Live Oak, 4 May: 13.0 µg/m³, 1.3× usual Live Oak, 5 May: 8.6 µg/m³, 0.8× usual Live Oak, 6 May: 22.0 µg/m³, 2.1× usual Live Oak, 7 May: 25.0 µg/m³, 2.4× usual Live Oak, 8 May: 43.2 µg/m³, 4.2× usual Live Oak, 9 May: 38.5 µg/m³, 3.7× usual Live Oak, 10 May: 9.7 µg/m³, 0.9× usual Live Oak, 11 May: 7.2 µg/m³, 0.7× usual Live Oak, 12 May: 19.0 µg/m³, 1.8× usual Live Oak, 13 May: 18.8 µg/m³, 1.8× usual Austin Austin, 4 May: 12.4 µg/m³, 1.2× usual Austin, 5 May: 8.3 µg/m³, 0.8× usual Austin, 6 May: 17.0 µg/m³, 1.6× usual Austin, 7 May: 21.0 µg/m³, 2.0× usual Austin, 8 May: 43.7 µg/m³, 4.1× usual Austin, 9 May: 33.5 µg/m³, 3.2× usual Austin, 10 May: 7.4 µg/m³, 0.7× usual Austin, 11 May: 7.3 µg/m³, 0.7× usual Austin, 12 May: 10.8 µg/m³, 1.0× usual Austin, 13 May: 10.0 µg/m³, 0.9× usual Heroica Matamoros Heroica Matamoros, 4 May: 14.7 µg/m³, 0.8× usual Heroica Matamoros, 5 May: 12.9 µg/m³, 0.7× usual Heroica Matamoros, 6 May: 14.0 µg/m³, 0.7× usual Heroica Matamoros, 7 May: 28.1 µg/m³, 1.4× usual Heroica Matamoros, 8 May: 42.7 µg/m³, 2.2× usual Heroica Matamoros, 9 May: 42.0 µg/m³, 2.2× usual Heroica Matamoros, 10 May: 45.6 µg/m³, 2.3× usual Heroica Matamoros, 11 May: 22.1 µg/m³, 1.1× usual Heroica Matamoros, 12 May: 27.4 µg/m³, 1.4× usual Heroica Matamoros, 13 May: 35.1 µg/m³, 1.8× usual San Marcos San Marcos, 4 May: 9.2 µg/m³, 1.0× usual San Marcos, 5 May: 5.7 µg/m³, 0.6× usual San Marcos, 6 May: 12.6 µg/m³, 1.4× usual San Marcos, 7 May: 18.3 µg/m³, 2.0× usual San Marcos, 8 May: 38.0 µg/m³, 4.1× usual San Marcos, 9 May: 28.6 µg/m³, 3.1× usual San Marcos, 10 May: 6.9 µg/m³, 0.7× usual San Marcos, 11 May: 6.9 µg/m³, 0.7× usual San Marcos, 12 May: 11.1 µg/m³, 1.2× usual San Marcos, 13 May: 8.9 µg/m³, 1.0× usual Corsicana Corsicana, 4 May: 7.9 µg/m³, 0.9× usual Corsicana, 5 May: 4.6 µg/m³, 0.5× usual Corsicana, 6 May: 10.4 µg/m³, 1.2× usual Corsicana, 7 May: 18.3 µg/m³, 2.1× usual Corsicana, 8 May: 37.0 µg/m³, 4.2× usual Corsicana, 9 May: 25.4 µg/m³, 2.9× usual Corsicana, 10 May: 5.3 µg/m³, 0.6× usual Corsicana, 11 May: 6.5 µg/m³, 0.7× usual Corsicana, 12 May: 6.2 µg/m³, 0.7× usual Corsicana, 13 May: 5.8 µg/m³, 0.7× usual Belton Belton, 4 May: 9.2 µg/m³, 1.2× usual Belton, 5 May: 5.9 µg/m³, 0.8× usual Belton, 6 May: 13.2 µg/m³, 1.8× usual Belton, 7 May: 18.1 µg/m³, 2.4× usual Belton, 8 May: 36.9 µg/m³, 5.0× usual Belton, 9 May: 29.9 µg/m³, 4.0× usual Belton, 10 May: 5.7 µg/m³, 0.8× usual Belton, 11 May: 5.5 µg/m³, 0.7× usual Belton, 12 May: no reading Belton, 13 May: 6.2 µg/m³, 0.8× usual Taylor Taylor, 4 May: 8.2 µg/m³, 1.0× usual Taylor, 5 May: 5.9 µg/m³, 0.7× usual Taylor, 6 May: 11.3 µg/m³, 1.4× usual Taylor, 7 May: 17.9 µg/m³, 2.2× usual Taylor, 8 May: 36.4 µg/m³, 4.4× usual Taylor, 9 May: 25.8 µg/m³, 3.1× usual Taylor, 10 May: 5.9 µg/m³, 0.7× usual Taylor, 11 May: 6.0 µg/m³, 0.7× usual Taylor, 12 May: 6.3 µg/m³, 0.8× usual Taylor, 13 May: 8.0 µg/m³, 1.0× usual College Station College Station, 4 May: 9.8 µg/m³, 1.0× usual College Station, 5 May: 7.7 µg/m³, 0.8× usual College Station, 6 May: 9.9 µg/m³, 1.1× usual College Station, 7 May: 22.1 µg/m³, 2.4× usual College Station, 8 May: 35.7 µg/m³, 3.8× usual College Station, 9 May: 27.1 µg/m³, 2.9× usual College Station, 10 May: 8.3 µg/m³, 0.9× usual College Station, 11 May: 7.5 µg/m³, 0.8× usual College Station, 12 May: 5.6 µg/m³, 0.6× usual College Station, 13 May: 7.8 µg/m³, 0.8× usual San Antonio San Antonio, 4 May: 12.5 µg/m³, 1.2× usual San Antonio, 5 May: 9.6 µg/m³, 0.9× usual San Antonio, 6 May: 18.0 µg/m³, 1.7× usual San Antonio, 7 May: 19.7 µg/m³, 1.9× usual San Antonio, 8 May: 32.2 µg/m³, 3.0× usual San Antonio, 9 May: 30.0 µg/m³, 2.8× usual San Antonio, 10 May: 9.6 µg/m³, 0.9× usual San Antonio, 11 May: 7.7 µg/m³, 0.7× usual San Antonio, 12 May: 13.8 µg/m³, 1.3× usual San Antonio, 13 May: 11.9 µg/m³, 1.1× usual Texarkana Texarkana, 4 May: 7.7 µg/m³, 0.8× usual Texarkana, 5 May: 7.9 µg/m³, 0.8× usual Texarkana, 6 May: 10.1 µg/m³, 1.1× usual Texarkana, 7 May: 18.1 µg/m³, 1.9× usual Texarkana, 8 May: 31.2 µg/m³, 3.3× usual Texarkana, 9 May: 12.7 µg/m³, 1.3× usual Texarkana, 10 May: 5.6 µg/m³, 0.6× usual Texarkana, 11 May: 7.5 µg/m³, 0.8× usual Texarkana, 12 May: 8.4 µg/m³, 0.9× usual Texarkana, 13 May: 8.1 µg/m³, 0.9× usual Dallas Dallas, 4 May: 10.1 µg/m³, 1.1× usual Dallas, 5 May: 6.3 µg/m³, 0.7× usual Dallas, 6 May: 14.4 µg/m³, 1.5× usual Dallas, 7 May: 16.3 µg/m³, 1.7× usual Dallas, 8 May: 29.2 µg/m³, 3.1× usual Dallas, 9 May: 14.9 µg/m³, 1.6× usual Dallas, 10 May: 3.6 µg/m³, 0.4× usual Dallas, 11 May: 5.2 µg/m³, 0.6× usual Dallas, 12 May: 7.6 µg/m³, 0.8× usual Dallas, 13 May: 6.9 µg/m³, 0.7× usual Saginaw Saginaw, 4 May: 17.0 µg/m³, 1.9× usual Saginaw, 5 May: 9.1 µg/m³, 1.0× usual Saginaw, 6 May: 17.7 µg/m³, 2.0× usual Saginaw, 7 May: 16.1 µg/m³, 1.8× usual Saginaw, 8 May: 28.3 µg/m³, 3.2× usual Saginaw, 9 May: 13.9 µg/m³, 1.6× usual Saginaw, 10 May: 4.8 µg/m³, 0.5× usual Saginaw, 11 May: 9.6 µg/m³, 1.1× usual Saginaw, 12 May: 16.0 µg/m³, 1.8× usual Saginaw, 13 May: 9.4 µg/m³, 1.1× usual Mission Bend Mission Bend, 4 May: 8.6 µg/m³, 0.8× usual Mission Bend, 5 May: 8.8 µg/m³, 0.9× usual Mission Bend, 6 May: 10.2 µg/m³, 1.0× usual Mission Bend, 7 May: 23.1 µg/m³, 2.2× usual Mission Bend, 8 May: 27.9 µg/m³, 2.7× usual Mission Bend, 9 May: 42.9 µg/m³, 4.2× usual Mission Bend, 10 May: 13.4 µg/m³, 1.3× usual Mission Bend, 11 May: 7.7 µg/m³, 0.7× usual Mission Bend, 12 May: 12.2 µg/m³, 1.2× usual Mission Bend, 13 May: 13.3 µg/m³, 1.3× usual Eagle Pass Eagle Pass, 4 May: 21.3 µg/m³, 2.0× usual Eagle Pass, 5 May: no reading Eagle Pass, 6 May: no reading Eagle Pass, 7 May: 18.1 µg/m³, 1.7× usual Eagle Pass, 8 May: 27.4 µg/m³, 2.6× usual Eagle Pass, 9 May: 27.7 µg/m³, 2.7× usual Eagle Pass, 10 May: 23.1 µg/m³, 2.2× usual Eagle Pass, 11 May: 15.8 µg/m³, 1.5× usual Eagle Pass, 12 May: 18.8 µg/m³, 1.8× usual Eagle Pass, 13 May: 20.2 µg/m³, 1.9× usual Houston Houston, 4 May: 10.5 µg/m³, 0.9× usual Houston, 5 May: 9.3 µg/m³, 0.8× usual Houston, 6 May: 12.5 µg/m³, 1.1× usual Houston, 7 May: 20.8 µg/m³, 1.7× usual Houston, 8 May: 26.9 µg/m³, 2.3× usual Houston, 9 May: 44.0 µg/m³, 3.7× usual Houston, 10 May: 12.7 µg/m³, 1.1× usual Houston, 11 May: 9.4 µg/m³, 0.8× usual Houston, 12 May: 11.0 µg/m³, 0.9× usual Houston, 13 May: 17.4 µg/m³, 1.5× usual Missouri City Missouri City, 4 May: 10.3 µg/m³, 1.1× usual Missouri City, 5 May: 9.4 µg/m³, 1.0× usual Missouri City, 6 May: 11.4 µg/m³, 1.2× usual Missouri City, 7 May: 19.7 µg/m³, 2.0× usual Missouri City, 8 May: 25.3 µg/m³, 2.6× usual Missouri City, 9 May: 39.1 µg/m³, 4.0× usual Missouri City, 10 May: 13.9 µg/m³, 1.4× usual Missouri City, 11 May: 9.3 µg/m³, 0.9× usual Missouri City, 12 May: 13.3 µg/m³, 1.4× usual Missouri City, 13 May: 17.7 µg/m³, 1.8× usual Baytown Baytown, 4 May: 7.8 µg/m³, 0.7× usual Baytown, 5 May: 9.5 µg/m³, 0.8× usual Baytown, 6 May: 12.5 µg/m³, 1.1× usual Baytown, 7 May: 15.0 µg/m³, 1.3× usual Baytown, 8 May: 21.2 µg/m³, 1.9× usual Baytown, 9 May: 40.0 µg/m³, 3.5× usual Baytown, 10 May: 11.5 µg/m³, 1.0× usual Baytown, 11 May: 9.0 µg/m³, 0.8× usual Baytown, 12 May: 11.4 µg/m³, 1.0× usual Baytown, 13 May: 16.3 µg/m³, 1.4× usual Pasadena Pasadena, 4 May: 9.0 µg/m³, 0.9× usual Pasadena, 5 May: 4.1 µg/m³, 0.4× usual Pasadena, 6 May: no reading Pasadena, 7 May: no reading Pasadena, 8 May: 13.8 µg/m³, 1.3× usual Pasadena, 9 May: 39.9 µg/m³, 3.8× usual Pasadena, 10 May: 13.5 µg/m³, 1.3× usual Pasadena, 11 May: 9.7 µg/m³, 0.9× usual Pasadena, 12 May: 10.7 µg/m³, 1.0× usual Pasadena, 13 May: 15.8 µg/m³, 1.5× usual Port Arthur Port Arthur, 4 May: 8.6 µg/m³, 0.9× usual Port Arthur, 5 May: 8.7 µg/m³, 0.9× usual Port Arthur, 6 May: 13.6 µg/m³, 1.4× usual Port Arthur, 7 May: 15.0 µg/m³, 1.6× usual Port Arthur, 8 May: 22.8 µg/m³, 2.4× usual Port Arthur, 9 May: 38.1 µg/m³, 4.0× usual Port Arthur, 10 May: 17.1 µg/m³, 1.8× usual Port Arthur, 11 May: 8.9 µg/m³, 0.9× usual Port Arthur, 12 May: 12.2 µg/m³, 1.3× usual Port Arthur, 13 May: 22.3 µg/m³, 2.3× usual Sulphur Sulphur, 4 May: 6.7 µg/m³, 0.8× usual Sulphur, 5 May: 7.1 µg/m³, 0.8× usual Sulphur, 6 May: 8.8 µg/m³, 1.0× usual Sulphur, 7 May: 11.1 µg/m³, 1.3× usual Sulphur, 8 May: 14.7 µg/m³, 1.7× usual Sulphur, 9 May: 38.0 µg/m³, 4.4× usual Sulphur, 10 May: 13.1 µg/m³, 1.5× usual Sulphur, 11 May: 5.6 µg/m³, 0.6× usual Sulphur, 12 May: 7.9 µg/m³, 0.9× usual Sulphur, 13 May: 17.7 µg/m³, 2.0× usual Cadereyta Jiménez Cadereyta Jiménez, 4 May: no reading Cadereyta Jiménez, 5 May: no reading Cadereyta Jiménez, 6 May: no reading Cadereyta Jiménez, 7 May: no reading Cadereyta Jiménez, 8 May: no reading Cadereyta Jiménez, 9 May: 35.8 µg/m³, 2.0× usual Cadereyta Jiménez, 10 May: 42.3 µg/m³, 2.4× usual Cadereyta Jiménez, 11 May: no reading Cadereyta Jiménez, 12 May: no reading Cadereyta Jiménez, 13 May: no reading La Porte La Porte, 4 May: 7.1 µg/m³, 0.7× usual La Porte, 5 May: 6.1 µg/m³, 0.6× usual La Porte, 6 May: 8.7 µg/m³, 0.9× usual La Porte, 7 May: 12.2 µg/m³, 1.3× usual La Porte, 8 May: 17.7 µg/m³, 1.9× usual La Porte, 9 May: 31.7 µg/m³, 3.3× usual La Porte, 10 May: 11.8 µg/m³, 1.2× usual La Porte, 11 May: 5.8 µg/m³, 0.6× usual La Porte, 12 May: 8.5 µg/m³, 0.9× usual La Porte, 13 May: 13.8 µg/m³, 1.5× usual Galveston Galveston, 4 May: 7.0 µg/m³, 0.8× usual Galveston, 5 May: 5.2 µg/m³, 0.6× usual Galveston, 6 May: 8.6 µg/m³, 0.9× usual Galveston, 7 May: 9.0 µg/m³, 1.0× usual Galveston, 8 May: 14.6 µg/m³, 1.6× usual Galveston, 9 May: 30.6 µg/m³, 3.4× usual Galveston, 10 May: 14.0 µg/m³, 1.5× usual Galveston, 11 May: 4.3 µg/m³, 0.5× usual Galveston, 12 May: 8.0 µg/m³, 0.9× usual Galveston, 13 May: 16.8 µg/m³, 1.8× usual Lafayette Lafayette, 4 May: 11.0 µg/m³, 1.5× usual Lafayette, 5 May: 7.5 µg/m³, 1.1× usual Lafayette, 6 May: 8.0 µg/m³, 1.1× usual Lafayette, 7 May: 9.1 µg/m³, 1.3× usual Lafayette, 8 May: 11.9 µg/m³, 1.7× usual Lafayette, 9 May: 25.8 µg/m³, 3.6× usual Lafayette, 10 May: 11.7 µg/m³, 1.6× usual Lafayette, 11 May: 10.2 µg/m³, 1.4× usual Lafayette, 12 May: 9.3 µg/m³, 1.3× usual Lafayette, 13 May: 11.8 µg/m³, 1.7× usual Baton Rouge Baton Rouge, 4 May: 8.3 µg/m³, 1.0× usual Baton Rouge, 5 May: 9.0 µg/m³, 1.0× usual Baton Rouge, 6 May: 9.1 µg/m³, 1.0× usual Baton Rouge, 7 May: 10.3 µg/m³, 1.2× usual Baton Rouge, 8 May: 10.5 µg/m³, 1.2× usual Baton Rouge, 9 May: 25.6 µg/m³, 2.9× usual Baton Rouge, 10 May: 13.4 µg/m³, 1.5× usual Baton Rouge, 11 May: 6.6 µg/m³, 0.8× usual Baton Rouge, 12 May: 9.8 µg/m³, 1.1× usual Baton Rouge, 13 May: 6.0 µg/m³, 0.7× usual Monterrey Monterrey, 4 May: no reading Monterrey, 5 May: no reading Monterrey, 6 May: no reading Monterrey, 7 May: no reading Monterrey, 8 May: no reading Monterrey, 9 May: 33.8 µg/m³, 1.6× usual Monterrey, 10 May: 47.0 µg/m³, 2.3× usual Monterrey, 11 May: no reading Monterrey, 12 May: no reading Monterrey, 13 May: 27.4 µg/m³, 1.3× usual 4 May 5 6 7 8 9 10 11 12 13 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
Belton Texas, United States 2 8 May 7.4 5.0× Taylor Texas, United States 2 8 May 8.3 4.4× Sulphur Louisiana, United States 1 9 May 8.7 4.4× Corsicana Texas, United States 2 8 May 8.8 4.2× Mission Bend Texas, United States 2 9 May 10.3 4.2× Live Oak Texas, United States 3 8 May 10.4 4.2× Austin Texas, United States 2 8 May 10.6 4.1× San Marcos Texas, United States 2 8 May 9.3 4.1× Corpus Christi Texas, United States 4 9 May 12.4 4.0× Missouri City Texas, United States 2 9 May 9.8 4.0× Port Arthur Texas, United States 1 9 May 9.6 4.0× Conroe Texas, United States 3 9 May 10.3 3.9× Mission Texas, United States 4 10 May 14.3 3.9× Pasadena Texas, United States 1 9 May 10.5 3.8× College Station Texas, United States 2 8 May 9.4 3.8× Houston Texas, United States 2 9 May 11.9 3.7× Lafayette Louisiana, United States 1 9 May 7.1 3.6× Edinburg Texas, United States 4 10 May 13.5 3.6× Baytown Texas, United States 1 9 May 11.4 3.5× Galveston Texas, United States 1 9 May 9.1 3.4× La Porte Texas, United States 1 9 May 9.5 3.3× Texarkana Texas, United States 1 8 May 9.5 3.3× Saginaw Texas, United States 1 8 May 8.8 3.2× Dallas Texas, United States 1 8 May 9.4 3.1× San Antonio Texas, United States 2 8 May 10.6 3.0× Baton Rouge Louisiana, United States 1 9 May 8.7 2.9× Eagle Pass Texas, United States 2 9 May 10.4 2.7× Cadereyta Jiménez Nuevo León, Mexico 2 10 May 17.5 2.4× Heroica Matamoros Tamaulipas, Mexico 3 10 May 19.5 2.3× Laredo Texas, United States 2 8 May 12.6 2.3× Monterrey Nuevo León, Mexico 1 10 May 20.5 2.3×
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 34 of 142 episodes in the United States and Mexico 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 Southern United States and Mexico, May 2024 31 Bars: cities reached; colour: the level of the episode's highest daily reading. All 142 .
Use this page SmogRank, Southern United States and Mexico, May 2024: 31 cities with PM2.5 at twice their usual or more, 7 to 10 May 2024, smogrank.com/episodes/2024-05-southern-united-states-and-mexico (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.
