SmogRank / Episodes / United States
Southern United States and Mexico, 7 to 10 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 Laredo Monterrey Cadereyta Jiménez Eagle Pass Baton Rouge San Antonio Dallas Saginaw Texarkana La Porte Galveston Heroica Matamoros Baytown Lafayette Edinburg Houston College Station Pasadena Conroe Mission Port Arthur Missouri City Corpus Christi San Marcos Austin Corsicana Mission Bend Live Oak Taylor Sulphur 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
Mission Mission, 4 May: 23.0 µg/m³ Mission, 5 May: 22.7 µg/m³ Mission, 6 May: 26.0 µg/m³ Mission, 7 May: 37.8 µg/m³, 2.5× its usual 15.0 Mission, 8 May: 43.2 µg/m³, 3.0× its usual 14.6 Mission, 9 May: 45.0 µg/m³, 3.1× its usual 14.6 Mission, 10 May: 55.4 µg/m³, 3.9× its usual 14.3 Mission, 11 May: 39.0 µg/m³ Mission, 12 May: 29.5 µg/m³ Mission, 13 May: 37.7 µg/m³ Edinburg Edinburg, 4 May: 17.9 µg/m³ Edinburg, 5 May: 18.0 µg/m³ Edinburg, 6 May: 20.1 µg/m³ Edinburg, 7 May: 31.8 µg/m³, 2.4× its usual 13.4 Edinburg, 8 May: 39.2 µg/m³, 2.9× its usual 13.5 Edinburg, 9 May: 38.2 µg/m³, 2.8× its usual 13.6 Edinburg, 10 May: 48.9 µg/m³, 3.6× its usual 13.5 Edinburg, 11 May: 34.1 µg/m³ Edinburg, 12 May: 25.2 µg/m³ Edinburg, 13 May: 33.8 µg/m³ Corpus Christi Corpus Christi, 4 May: 16.3 µg/m³ Corpus Christi, 5 May: 16.5 µg/m³ Corpus Christi, 6 May: 14.5 µg/m³ Corpus Christi, 7 May: 30.5 µg/m³, 2.4× its usual 12.9 Corpus Christi, 8 May: 43.3 µg/m³, 3.4× its usual 12.6 Corpus Christi, 9 May: 50.1 µg/m³, 4.0× its usual 12.4 Corpus Christi, 10 May: 34.8 µg/m³, 2.9× its usual 12.0 Corpus Christi, 11 May: 17.3 µg/m³ Corpus Christi, 12 May: 30.5 µg/m³ Corpus Christi, 13 May: 24.3 µg/m³ Laredo Laredo, 4 May: 25.2 µg/m³ Laredo, 5 May: 15.7 µg/m³ Laredo, 6 May: 20.4 µg/m³ Laredo, 7 May: 28.7 µg/m³, 2.2× its usual 12.9 Laredo, 8 May: 29.1 µg/m³, 2.3× its usual 12.6 Laredo, 9 May: no reading Laredo, 10 May: no reading Laredo, 11 May: 20.6 µg/m³ Laredo, 12 May: 21.1 µg/m³ Laredo, 13 May: no reading Heroica Matamoros Heroica Matamoros, 4 May: 14.7 µg/m³ Heroica Matamoros, 5 May: 12.9 µg/m³ Heroica Matamoros, 6 May: 14.0 µg/m³ Heroica Matamoros, 7 May: 28.1 µg/m³, 2.1× its usual 13.4 Heroica Matamoros, 8 May: 42.7 µg/m³, 3.2× its usual 13.3 Heroica Matamoros, 9 May: 42.0 µg/m³, 3.1× its usual 13.4 Heroica Matamoros, 10 May: 45.6 µg/m³, 3.4× its usual 13.4 Heroica Matamoros, 11 May: 22.1 µg/m³ Heroica Matamoros, 12 May: 27.4 µg/m³ Heroica Matamoros, 13 May: 35.1 µg/m³ Conroe Conroe, 4 May: 7.8 µg/m³ Conroe, 5 May: 7.2 µg/m³ Conroe, 6 May: 15.0 µg/m³ Conroe, 7 May: 27.4 µg/m³, 2.6× its usual 10.5 Conroe, 8 May: 27.3 µg/m³, 2.6× its usual 10.4 Conroe, 9 May: 40.1 µg/m³, 3.9× its usual 10.3 Conroe, 10 May: 11.4 µg/m³ Conroe, 11 May: 10.0 µg/m³ Conroe, 12 May: 7.8 µg/m³ Conroe, 13 May: 14.7 µg/m³ Live Oak Live Oak, 4 May: 13.0 µg/m³ Live Oak, 5 May: 8.6 µg/m³ Live Oak, 6 May: 22.0 µg/m³ Live Oak, 7 May: 25.0 µg/m³, 2.4× its usual 10.6 Live Oak, 8 May: 43.2 µg/m³, 4.2× its usual 10.4 Live Oak, 9 May: 38.5 µg/m³, 3.9× its usual 9.8 Live Oak, 10 May: 9.7 µg/m³ Live Oak, 11 May: 7.2 µg/m³ Live Oak, 12 May: 19.0 µg/m³ Live Oak, 13 May: 18.8 µg/m³ Austin Austin, 4 May: 12.4 µg/m³ Austin, 5 May: 8.3 µg/m³ Austin, 6 May: 17.0 µg/m³ Austin, 7 May: 21.0 µg/m³ Austin, 8 May: 43.7 µg/m³, 4.1× its usual 10.6 Austin, 9 May: 33.5 µg/m³, 3.2× its usual 10.6 Austin, 10 May: 7.4 µg/m³ Austin, 11 May: 7.3 µg/m³ Austin, 12 May: 10.8 µg/m³ Austin, 13 May: 10.0 µg/m³ San Marcos San Marcos, 4 May: 9.2 µg/m³ San Marcos, 5 May: 5.7 µg/m³ San Marcos, 6 May: 12.6 µg/m³ San Marcos, 7 May: 18.3 µg/m³ San Marcos, 8 May: 38.0 µg/m³, 4.1× its usual 9.3 San Marcos, 9 May: 28.6 µg/m³, 3.1× its usual 9.1 San Marcos, 10 May: 6.9 µg/m³ San Marcos, 11 May: 6.9 µg/m³ San Marcos, 12 May: 11.1 µg/m³ San Marcos, 13 May: 8.9 µg/m³ Corsicana Corsicana, 4 May: 7.9 µg/m³ Corsicana, 5 May: 4.6 µg/m³ Corsicana, 6 May: 10.4 µg/m³ Corsicana, 7 May: 18.3 µg/m³ Corsicana, 8 May: 37.0 µg/m³, 4.2× its usual 8.8 Corsicana, 9 May: 25.4 µg/m³, 2.9× its usual 8.8 Corsicana, 10 May: 5.3 µg/m³ Corsicana, 11 May: 6.5 µg/m³ Corsicana, 12 May: 6.2 µg/m³ Corsicana, 13 May: 5.8 µg/m³ Belton Belton, 4 May: 9.2 µg/m³ Belton, 5 May: 5.9 µg/m³ Belton, 6 May: 13.2 µg/m³ Belton, 7 May: 18.1 µg/m³ Belton, 8 May: 36.9 µg/m³, 5.0× its usual 7.4 Belton, 9 May: 29.9 µg/m³, 4.0× its usual 7.4 Belton, 10 May: 5.7 µg/m³ Belton, 11 May: 5.5 µg/m³ Belton, 12 May: no reading Belton, 13 May: 6.2 µg/m³ Taylor Taylor, 4 May: 8.2 µg/m³ Taylor, 5 May: 5.9 µg/m³ Taylor, 6 May: 11.3 µg/m³ Taylor, 7 May: 17.9 µg/m³ Taylor, 8 May: 36.4 µg/m³, 4.4× its usual 8.3 Taylor, 9 May: 25.8 µg/m³, 3.2× its usual 8.0 Taylor, 10 May: 5.9 µg/m³ Taylor, 11 May: 6.0 µg/m³ Taylor, 12 May: 6.3 µg/m³ Taylor, 13 May: 8.0 µg/m³ College Station College Station, 4 May: 9.8 µg/m³ College Station, 5 May: 7.7 µg/m³ College Station, 6 May: 9.9 µg/m³ College Station, 7 May: 22.1 µg/m³ College Station, 8 May: 35.7 µg/m³, 3.8× its usual 9.4 College Station, 9 May: 27.1 µg/m³, 2.9× its usual 9.4 College Station, 10 May: 8.3 µg/m³ College Station, 11 May: 7.5 µg/m³ College Station, 12 May: 5.6 µg/m³ College Station, 13 May: 7.8 µg/m³ San Antonio San Antonio, 4 May: 12.5 µg/m³ San Antonio, 5 May: 9.6 µg/m³ San Antonio, 6 May: 18.0 µg/m³ San Antonio, 7 May: 19.7 µg/m³ San Antonio, 8 May: 32.2 µg/m³, 3.0× its usual 10.6 San Antonio, 9 May: 30.0 µg/m³, 2.9× its usual 10.4 San Antonio, 10 May: 9.6 µg/m³ San Antonio, 11 May: 7.7 µg/m³ San Antonio, 12 May: 13.8 µg/m³ San Antonio, 13 May: 11.9 µg/m³ Texarkana Texarkana, 4 May: 7.7 µg/m³ Texarkana, 5 May: 7.9 µg/m³ Texarkana, 6 May: 10.1 µg/m³ Texarkana, 7 May: 18.1 µg/m³ Texarkana, 8 May: 31.2 µg/m³, 3.3× its usual 9.5 Texarkana, 9 May: 12.7 µg/m³ Texarkana, 10 May: 5.6 µg/m³ Texarkana, 11 May: 7.5 µg/m³ Texarkana, 12 May: 8.4 µg/m³ Texarkana, 13 May: 8.1 µg/m³ Dallas Dallas, 4 May: 10.1 µg/m³ Dallas, 5 May: 6.3 µg/m³ Dallas, 6 May: 14.4 µg/m³ Dallas, 7 May: 16.3 µg/m³ Dallas, 8 May: 29.2 µg/m³, 3.1× its usual 9.4 Dallas, 9 May: 14.9 µg/m³ Dallas, 10 May: 3.6 µg/m³ Dallas, 11 May: 5.2 µg/m³ Dallas, 12 May: 7.6 µg/m³ Dallas, 13 May: 6.9 µg/m³ Saginaw Saginaw, 4 May: 17.0 µg/m³ Saginaw, 5 May: 9.1 µg/m³ Saginaw, 6 May: 17.7 µg/m³ Saginaw, 7 May: 16.1 µg/m³ Saginaw, 8 May: 28.3 µg/m³, 3.2× its usual 8.8 Saginaw, 9 May: 13.9 µg/m³ Saginaw, 10 May: 4.8 µg/m³ Saginaw, 11 May: 9.6 µg/m³ Saginaw, 12 May: 16.0 µg/m³ Saginaw, 13 May: 9.4 µg/m³ Mission Bend Mission Bend, 4 May: 8.6 µg/m³ Mission Bend, 5 May: 8.8 µg/m³ Mission Bend, 6 May: 10.2 µg/m³ Mission Bend, 7 May: 23.1 µg/m³ Mission Bend, 8 May: 27.9 µg/m³, 2.7× its usual 10.4 Mission Bend, 9 May: 42.9 µg/m³, 4.2× its usual 10.3 Mission Bend, 10 May: 13.4 µg/m³ Mission Bend, 11 May: 7.7 µg/m³ Mission Bend, 12 May: 12.2 µg/m³ Mission Bend, 13 May: 13.3 µg/m³ Eagle Pass Eagle Pass, 4 May: 21.3 µg/m³ Eagle Pass, 5 May: no reading Eagle Pass, 6 May: no reading Eagle Pass, 7 May: 18.1 µg/m³ Eagle Pass, 8 May: 27.4 µg/m³, 2.6× its usual 10.5 Eagle Pass, 9 May: 27.7 µg/m³, 2.7× its usual 10.4 Eagle Pass, 10 May: 23.1 µg/m³ Eagle Pass, 11 May: 15.8 µg/m³ Eagle Pass, 12 May: 18.8 µg/m³ Eagle Pass, 13 May: 20.2 µg/m³ Houston Houston, 4 May: 10.5 µg/m³ Houston, 5 May: 9.3 µg/m³ Houston, 6 May: 12.5 µg/m³ Houston, 7 May: 20.8 µg/m³ Houston, 8 May: 26.9 µg/m³, 2.2× its usual 12.0 Houston, 9 May: 44.0 µg/m³, 3.7× its usual 11.9 Houston, 10 May: 12.7 µg/m³ Houston, 11 May: 9.4 µg/m³ Houston, 12 May: 11.0 µg/m³ Houston, 13 May: 17.4 µg/m³ Missouri City Missouri City, 4 May: 10.3 µg/m³ Missouri City, 5 May: 9.4 µg/m³ Missouri City, 6 May: 11.4 µg/m³ Missouri City, 7 May: 19.7 µg/m³ Missouri City, 8 May: 25.3 µg/m³, 2.6× its usual 9.8 Missouri City, 9 May: 39.1 µg/m³, 4.0× its usual 9.8 Missouri City, 10 May: 13.9 µg/m³ Missouri City, 11 May: 9.3 µg/m³ Missouri City, 12 May: 13.3 µg/m³ Missouri City, 13 May: 17.7 µg/m³ Baytown Baytown, 4 May: 7.8 µg/m³ Baytown, 5 May: 9.5 µg/m³ Baytown, 6 May: 12.5 µg/m³ Baytown, 7 May: 15.0 µg/m³ Baytown, 8 May: 21.2 µg/m³ Baytown, 9 May: 40.0 µg/m³, 3.5× its usual 11.4 Baytown, 10 May: 11.5 µg/m³ Baytown, 11 May: 9.0 µg/m³ Baytown, 12 May: 11.4 µg/m³ Baytown, 13 May: 16.3 µg/m³ Pasadena Pasadena, 4 May: 9.0 µg/m³ Pasadena, 5 May: 4.1 µg/m³ Pasadena, 6 May: no reading Pasadena, 7 May: no reading Pasadena, 8 May: 13.8 µg/m³ Pasadena, 9 May: 39.9 µg/m³, 3.8× its usual 10.5 Pasadena, 10 May: 13.5 µg/m³ Pasadena, 11 May: 9.7 µg/m³ Pasadena, 12 May: 10.7 µg/m³ Pasadena, 13 May: 15.8 µg/m³ Port Arthur Port Arthur, 4 May: 8.6 µg/m³ Port Arthur, 5 May: 8.7 µg/m³ Port Arthur, 6 May: 13.6 µg/m³ Port Arthur, 7 May: 15.0 µg/m³ Port Arthur, 8 May: 22.8 µg/m³ Port Arthur, 9 May: 38.1 µg/m³, 4.0× its usual 9.6 Port Arthur, 10 May: 17.1 µg/m³ Port Arthur, 11 May: 8.9 µg/m³ Port Arthur, 12 May: 12.2 µg/m³ Port Arthur, 13 May: 22.3 µg/m³ Sulphur Sulphur, 4 May: 6.7 µg/m³ Sulphur, 5 May: 7.1 µg/m³ Sulphur, 6 May: 8.8 µg/m³ Sulphur, 7 May: 11.1 µg/m³ Sulphur, 8 May: 14.7 µg/m³ Sulphur, 9 May: 38.0 µg/m³, 4.4× its usual 8.7 Sulphur, 10 May: 13.1 µg/m³ Sulphur, 11 May: 5.6 µg/m³ Sulphur, 12 May: 7.9 µg/m³ Sulphur, 13 May: 17.7 µg/m³ 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, 2.1× its usual 17.1 Cadereyta Jiménez, 10 May: 42.3 µg/m³, 2.4× its usual 17.5 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 La Porte, 5 May: 6.1 µg/m³ La Porte, 6 May: 8.7 µg/m³ La Porte, 7 May: 12.2 µg/m³ La Porte, 8 May: 17.7 µg/m³ La Porte, 9 May: 31.7 µg/m³, 3.3× its usual 9.5 La Porte, 10 May: 11.8 µg/m³ La Porte, 11 May: 5.8 µg/m³ La Porte, 12 May: 8.5 µg/m³ La Porte, 13 May: 13.8 µg/m³ Galveston Galveston, 4 May: 7.0 µg/m³ Galveston, 5 May: 5.2 µg/m³ Galveston, 6 May: 8.6 µg/m³ Galveston, 7 May: 9.0 µg/m³ Galveston, 8 May: 14.6 µg/m³ Galveston, 9 May: 30.6 µg/m³, 3.4× its usual 9.1 Galveston, 10 May: 14.0 µg/m³ Galveston, 11 May: 4.3 µg/m³ Galveston, 12 May: 8.0 µg/m³ Galveston, 13 May: 16.8 µg/m³ Lafayette Lafayette, 4 May: 11.0 µg/m³ Lafayette, 5 May: 7.5 µg/m³ Lafayette, 6 May: 8.0 µg/m³ Lafayette, 7 May: 9.1 µg/m³ Lafayette, 8 May: 11.9 µg/m³ Lafayette, 9 May: 25.8 µg/m³, 3.6× its usual 7.1 Lafayette, 10 May: 11.7 µg/m³ Lafayette, 11 May: 10.2 µg/m³ Lafayette, 12 May: 9.3 µg/m³ Lafayette, 13 May: 11.8 µg/m³ Baton Rouge Baton Rouge, 4 May: 8.3 µg/m³ Baton Rouge, 5 May: 9.0 µg/m³ Baton Rouge, 6 May: 9.1 µg/m³ Baton Rouge, 7 May: 10.3 µg/m³ Baton Rouge, 8 May: 10.5 µg/m³ Baton Rouge, 9 May: 25.6 µg/m³, 2.9× its usual 8.7 Baton Rouge, 10 May: 13.4 µg/m³ Baton Rouge, 11 May: 6.6 µg/m³ Baton Rouge, 12 May: 9.8 µg/m³ Baton Rouge, 13 May: 6.0 µg/m³ 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 Monterrey, 10 May: 47.0 µg/m³, 2.3× its usual 20.5 Monterrey, 11 May: no reading Monterrey, 12 May: no reading Monterrey, 13 May: 27.4 µg/m³ 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× Sulphur Louisiana, United States 1 9 May 8.7 4.4× Taylor Texas, United States 2 8 May 8.3 4.4× Live Oak Texas, United States 3 8 May 10.4 4.2× Mission Bend Texas, United States 2 9 May 10.3 4.2× Corsicana Texas, United States 2 8 May 8.8 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× Mission Texas, United States 4 10 May 14.3 3.9× Conroe Texas, United States 3 9 May 10.3 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× Edinburg Texas, United States 4 10 May 13.5 3.6× Lafayette Louisiana, United States 1 9 May 7.1 3.6× Baytown Texas, United States 1 9 May 11.4 3.5× Heroica Matamoros Tamaulipas, Mexico 4 10 May 13.4 3.4× 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× Monterrey Nuevo León, Mexico 1 10 May 20.5 2.3× Laredo Texas, United States 2 8 May 12.6 2.3×
Daily means in µg/m³, over the days each city counted in this episode. Highest: its highest of those days. Usual: the city's median for the time of year of that day (its days within 21 days of the date, every year, leaving out the week around it). Above usual: its highest day against that, with a usual under 5 µg/m³ taken as 5.
Against other episodes in the United States and Mexico
Number 34 of 141 episodes in the United States and Mexico since our records began, by cities reached.
Eastern United States and Canada, 25 June to 2 July 2023 280 North-eastern United States and Canada, July 2026 264 Eastern United States and Canada, May and June 2023 261 North-eastern United States and Canada, 30 July to 9 August 2025 241 Eastern United States and Canada, July 2023 240 North-eastern United States and Canada, 3 to 9 June 2025 196 Eastern United States and Canada, 14 to 19 June 2023 161 North-eastern United States and Canada, 12 to 16 July 2025 119 North-western United States and Canada, August 2023 110 North-eastern United States and Canada, 10 to 14 June 2025 104 North-western United States and Canada, 4 to 11 August 2026 99 North-eastern United States and Canada, 14 to 19 February 2026 96 Southern United States and Mexico, 7 to 10 May 2024 31 Bars: cities reached; colour: the level of the episode's highest daily reading. All 141 .
Use this page SmogRank, Southern United States and Mexico, 7 to 10 May 2024: 31 cities with PM2.5 at twice their usual or more, 7 to 10 May 2024, smogrank.com/episodes/2024-05-07-southern-united-states-and-mexico (accessed 4 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.
