SmogRank / Episodes / United States

Southern United States and Mexico, 15 to 16 May 2024

For 2 days, from 15 to 16 May 2024, 8 cities in the United States and Mexico had PM2.5 at least twice their usual for the time of year. The worst reading was Port Isabel, Texas, United States: 69.0 µg/m³ on 16 May, about 4.9× its usual 14.1. Ended 16 May.

Likely smoke from firesFires were detected within 300 km of the city on 60% of the counted city-days and smoke was mapped over the city on 100%. Satellites see crop, field and forest fires alike, so this doesn't say which burned.
Cities reached8in 2 countries
Days215 to 16 May 2024
Worst day16 May6 cities counted
Furthest above usual4.9×Port Isabel

Day by day

16 May 6 cities at twice their usual or more
LaredoCadereyta JiménezCiudad General EscobedoMonterreySanta CatarinaSan AntonioWindcrestHelotesLive OakSaltilloMissouri CitySeabrookGalvestonCiudad Benito JuárezCiudad ApodacaEagle PassHeroica MatamorosCorpus ChristiEdinburgMissionPort Isabel
12 May13141516171819
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, 12 May: 49.4 µg/m³Ciudad Benito Juárez, 13 May: no readingCiudad Benito Juárez, 14 May: no readingCiudad Benito Juárez, 15 May: 44.9 µg/m³, 2.0× its usual 22.0Ciudad Benito Juárez, 16 May: no readingCiudad Benito Juárez, 17 May: no readingCiudad Benito Juárez, 18 May: no readingCiudad Benito Juárez, 19 May: no readingCiudad ApodacaCiudad Apodaca, 12 May: no readingCiudad Apodaca, 13 May: no readingCiudad Apodaca, 14 May: no readingCiudad Apodaca, 15 May: 37.4 µg/m³, 2.5× its usual 15.0Ciudad Apodaca, 16 May: no readingCiudad Apodaca, 17 May: no readingCiudad Apodaca, 18 May: no readingCiudad Apodaca, 19 May: no readingMissionMission, 12 May: 29.5 µg/m³Mission, 13 May: 37.7 µg/m³Mission, 14 May: 13.1 µg/m³Mission, 15 May: 36.7 µg/m³, 2.4× its usual 15.1Mission, 16 May: 51.2 µg/m³, 3.4× its usual 15.2Mission, 17 May: 20.9 µg/m³Mission, 18 May: 25.6 µg/m³Mission, 19 May: 39.1 µg/m³Port IsabelPort Isabel, 12 May: 42.8 µg/m³Port Isabel, 13 May: 46.6 µg/m³Port Isabel, 14 May: 27.5 µg/m³Port Isabel, 15 May: 32.5 µg/m³, 2.3× its usual 14.1Port Isabel, 16 May: 69.0 µg/m³, 4.9× its usual 14.1Port Isabel, 17 May: 82.0 µg/m³Port Isabel, 18 May: 55.9 µg/m³Port Isabel, 19 May: 52.5 µg/m³EdinburgEdinburg, 12 May: 25.2 µg/m³Edinburg, 13 May: 33.8 µg/m³Edinburg, 14 May: 12.4 µg/m³Edinburg, 15 May: 29.0 µg/m³, 2.1× its usual 13.7Edinburg, 16 May: 46.3 µg/m³, 3.4× its usual 13.7Edinburg, 17 May: 18.8 µg/m³Edinburg, 18 May: 23.7 µg/m³Edinburg, 19 May: 30.5 µg/m³Heroica MatamorosHeroica Matamoros, 12 May: 27.4 µg/m³Heroica Matamoros, 13 May: 35.1 µg/m³Heroica Matamoros, 14 May: 12.0 µg/m³Heroica Matamoros, 15 May: 24.6 µg/m³Heroica Matamoros, 16 May: 41.7 µg/m³, 3.0× its usual 13.8Heroica Matamoros, 17 May: 33.8 µg/m³Heroica Matamoros, 18 May: 27.6 µg/m³Heroica Matamoros, 19 May: 36.8 µg/m³Corpus ChristiCorpus Christi, 12 May: 30.5 µg/m³Corpus Christi, 13 May: 24.3 µg/m³Corpus Christi, 14 May: 11.0 µg/m³Corpus Christi, 15 May: 12.7 µg/m³Corpus Christi, 16 May: 38.8 µg/m³, 3.1× its usual 12.5Corpus Christi, 17 May: 10.1 µg/m³Corpus Christi, 18 May: 23.0 µg/m³Corpus Christi, 19 May: 32.2 µg/m³Eagle PassEagle Pass, 12 May: 18.8 µg/m³Eagle Pass, 13 May: 20.2 µg/m³Eagle Pass, 14 May: 6.5 µg/m³Eagle Pass, 15 May: 15.7 µg/m³Eagle Pass, 16 May: 30.5 µg/m³, 2.9× its usual 10.5Eagle Pass, 17 May: no readingEagle Pass, 18 May: 7.8 µg/m³Eagle Pass, 19 May: no reading12 May13141516171819
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
Port IsabelTexas, United States2 69.016 May14.14.9×
MissionTexas, United States2 51.216 May15.23.4×
EdinburgTexas, United States2 46.316 May13.73.4×
Corpus ChristiTexas, United States1 38.816 May12.53.1×
Heroica MatamorosTamaulipas, Mexico1 41.716 May13.83.0×
Eagle PassTexas, United States1 30.516 May10.52.9×
Ciudad ApodacaNuevo León, Mexico1 37.415 May15.02.5×
Ciudad Benito JuárezNuevo León, Mexico1 44.915 May22.02.0×

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 158 of 163 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 163.

Use this page

SmogRank, Southern United States and Mexico, 15 to 16 May 2024: 8 cities with PM2.5 at twice their usual or more, 15 to 16 May 2024, smogrank.com/episodes/2024-05-15-southern-united-states-and-mexico (accessed 5 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. Fire detections from NASA FIRMS; smoke maps from NOAA HMS.