SmogRank / Episodes / United States

Southern United States and Mexico, April 2024

For 1 day, on 1 April 2024, 9 cities in the United States and Mexico had PM2.5 at least twice their usual for the time of year. The worst reading was Ciudad Benito Juárez, Nuevo León, Mexico: 62.7 µg/m³ on 1 April, about 3.4× its usual 18.2.

No cause namedWe have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached9in 2 countries
Days11 April 2024
Worst day1 April9 cities counted
Furthest above usual4.0×Live Oak

Day by day

1 April 9 cities at twice their usual or more
San AntonioPiedras NegrasHeroica MatamorosCiudad General EscobedoJardines de la SillaMonterreyGarcíaSanta CatarinaSan MarcosMission BendMissouri CityHoustonPasadenaLa PorteGalvestonBaytownCiudad ApodacaCadereyta JiménezLaredoCorpus ChristiEdinburgEagle PassCiudad Benito JuárezMissionLive Oak
29 Mar30311 Apr234
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

Ciudad Benito JuárezCiudad Benito Juárez, 29 March: 13.3 µg/m³, 0.7× usualCiudad Benito Juárez, 30 March: 18.9 µg/m³, 1.0× usualCiudad Benito Juárez, 31 March: 33.7 µg/m³, 1.9× usualCiudad Benito Juárez, 1 April: 62.7 µg/m³, 3.4× usualCiudad Benito Juárez, 2 April: 28.7 µg/m³, 1.6× usualCiudad Benito Juárez, 3 April: no readingCiudad Benito Juárez, 4 April: 16.2 µg/m³, 0.9× usualCadereyta JiménezCadereyta Jiménez, 29 March: 11.7 µg/m³, 0.7× usualCadereyta Jiménez, 30 March: 12.8 µg/m³, 0.8× usualCadereyta Jiménez, 31 March: 21.8 µg/m³, 1.4× usualCadereyta Jiménez, 1 April: 45.0 µg/m³, 2.9× usualCadereyta Jiménez, 2 April: 17.4 µg/m³, 1.1× usualCadereyta Jiménez, 3 April: no readingCadereyta Jiménez, 4 April: 11.1 µg/m³, 0.7× usualCiudad ApodacaCiudad Apodaca, 29 March: 15.0 µg/m³, 1.0× usualCiudad Apodaca, 30 March: 14.3 µg/m³, 1.0× usualCiudad Apodaca, 31 March: 26.2 µg/m³, 1.8× usualCiudad Apodaca, 1 April: 42.0 µg/m³, 2.9× usualCiudad Apodaca, 2 April: 19.4 µg/m³, 1.3× usualCiudad Apodaca, 3 April: no readingCiudad Apodaca, 4 April: 19.3 µg/m³, 1.3× usualMissionMission, 29 March: 6.5 µg/m³, 0.7× usualMission, 30 March: 11.5 µg/m³, 1.2× usualMission, 31 March: 20.7 µg/m³, 2.1× usualMission, 1 April: 36.7 µg/m³, 3.8× usualMission, 2 April: 22.3 µg/m³, 2.3× usualMission, 3 April: 3.8 µg/m³, 0.4× usualMission, 4 April: 9.6 µg/m³, 1.0× usualEdinburgEdinburg, 29 March: 5.7 µg/m³, 0.6× usualEdinburg, 30 March: 7.5 µg/m³, 0.8× usualEdinburg, 31 March: 15.9 µg/m³, 1.6× usualEdinburg, 1 April: 31.0 µg/m³, 3.1× usualEdinburg, 2 April: 19.6 µg/m³, 2.0× usualEdinburg, 3 April: 4.2 µg/m³, 0.4× usualEdinburg, 4 April: 7.7 µg/m³, 0.8× usualLive OakLive Oak, 29 March: 5.2 µg/m³, 0.7× usualLive Oak, 30 March: 7.4 µg/m³, 1.0× usualLive Oak, 31 March: 13.9 µg/m³, 1.8× usualLive Oak, 1 April: 30.1 µg/m³, 4.0× usualLive Oak, 2 April: 14.7 µg/m³, 1.9× usualLive Oak, 3 April: 5.7 µg/m³, 0.8× usualLive Oak, 4 April: 8.1 µg/m³, 1.1× usualLaredoLaredo, 29 March: 5.5 µg/m³, 0.6× usualLaredo, 30 March: 8.1 µg/m³, 0.9× usualLaredo, 31 March: 17.3 µg/m³, 1.8× usualLaredo, 1 April: 27.9 µg/m³, 3.0× usualLaredo, 2 April: 14.4 µg/m³, 1.5× usualLaredo, 3 April: 4.4 µg/m³, 0.5× usualLaredo, 4 April: 5.1 µg/m³, 0.5× usualCorpus ChristiCorpus Christi, 29 March: 5.8 µg/m³, 0.6× usualCorpus Christi, 30 March: 7.0 µg/m³, 0.8× usualCorpus Christi, 31 March: 15.1 µg/m³, 1.6× usualCorpus Christi, 1 April: 27.7 µg/m³, 3.0× usualCorpus Christi, 2 April: 17.1 µg/m³, 1.8× usualCorpus Christi, 3 April: 4.7 µg/m³, 0.5× usualCorpus Christi, 4 April: 7.6 µg/m³, 0.8× usualEagle PassEagle Pass, 29 March: 5.3 µg/m³, 0.7× usualEagle Pass, 30 March: 7.6 µg/m³, 1.0× usualEagle Pass, 31 March: 13.3 µg/m³, 1.7× usualEagle Pass, 1 April: 26.5 µg/m³, 3.4× usualEagle Pass, 2 April: 5.5 µg/m³, 0.7× usualEagle Pass, 3 April: 5.0 µg/m³, 0.6× usualEagle Pass, 4 April: 6.1 µg/m³, 0.8× usual29 Mar30311 Apr234
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.
Good0–50
Moderate51–100
Sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

Every city it reached

CityDaysHighestUsualAbove usual
Live OakTexas, United States1 30.11 April7.64.0×
MissionTexas, United States1 36.71 April9.73.8×
Ciudad Benito JuárezNuevo León, Mexico1 62.71 April18.23.4×
Eagle PassTexas, United States1 26.51 April7.93.4×
EdinburgTexas, United States1 31.01 April10.03.1×
Corpus ChristiTexas, United States1 27.71 April9.33.0×
LaredoTexas, United States1 27.91 April9.43.0×
Ciudad ApodacaNuevo León, Mexico1 42.01 April14.52.9×
Cadereyta JiménezNuevo León, Mexico1 45.01 April15.72.9×

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 116 of 142 episodes in the United States and Mexico since our records began, by cities reached.

Bars: cities reached; colour: the level of the episode's highest daily reading. All 142.

Use this page

SmogRank, Southern United States and Mexico, April 2024: 9 cities with PM2.5 at twice their usual or more, 1 April 2024, smogrank.com/episodes/2024-04-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.