SmogRank / Episodes / United States

South-western United States, March 2025

For 1 day, on 18 March 2025, 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 El Paso, Texas, United States: 230.0 µg/m³ on 18 March, about 26× its usual 8.8.

No cause namedWe have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached9in 2 countries
Days118 March 2025
Worst day18 March9 cities counted
Furthest above usual34×Sunland Park

Day by day

18 March 9 cities at twice their usual or more
Rio RanchoAlbuquerqueSocorroCiudad JuárezOdessaLubbockHobbsLas CrucesEl PasoSunland Park
15 Mar161718192021
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

Sunland ParkSunland Park, 15 March: 11.3 µg/m³, 1.9× usualSunland Park, 16 March: 5.3 µg/m³, 0.9× usualSunland Park, 17 March: 42.7 µg/m³, 7.1× usualSunland Park, 18 March: 204.0 µg/m³, 34× usualSunland Park, 19 March: 10.3 µg/m³, 1.7× usualSunland Park, 20 March: 13.3 µg/m³, 2.2× usualSunland Park, 21 March: 13.5 µg/m³, 2.3× usualEl PasoEl Paso, 15 March: no readingEl Paso, 16 March: no readingEl Paso, 17 March: 13.2 µg/m³, 1.5× usualEl Paso, 18 March: 230.0 µg/m³, 26× usualEl Paso, 19 March: 5.7 µg/m³, 0.6× usualEl Paso, 20 March: 10.9 µg/m³, 1.2× usualEl Paso, 21 March: 18.8 µg/m³, 2.1× usualCiudad JuárezCiudad Juárez, 15 March: 11.0 µg/m³, 0.7× usualCiudad Juárez, 16 March: 7.8 µg/m³, 0.5× usualCiudad Juárez, 17 March: 22.2 µg/m³, 1.5× usualCiudad Juárez, 18 March: 187.5 µg/m³, 13× usualCiudad Juárez, 19 March: 7.4 µg/m³, 0.5× usualCiudad Juárez, 20 March: 16.9 µg/m³, 1.1× usualCiudad Juárez, 21 March: 23.1 µg/m³, 1.5× usualLas CrucesLas Cruces, 15 March: 4.1 µg/m³, 0.8× usualLas Cruces, 16 March: 3.2 µg/m³, 0.6× usualLas Cruces, 17 March: 10.2 µg/m³, 2.0× usualLas Cruces, 18 March: 112.0 µg/m³, 22× usualLas Cruces, 19 March: 2.7 µg/m³, 0.5× usualLas Cruces, 20 March: 5.1 µg/m³, 1.0× usualLas Cruces, 21 March: 4.0 µg/m³, 0.8× usualHobbsHobbs, 15 March: no readingHobbs, 16 March: no readingHobbs, 17 March: 7.1 µg/m³, 1.2× usualHobbs, 18 March: 105.0 µg/m³, 18× usualHobbs, 19 March: 9.9 µg/m³, 1.7× usualHobbs, 20 March: 5.8 µg/m³, 1.0× usualHobbs, 21 March: 8.2 µg/m³, 1.4× usualOdessaOdessa, 15 March: 10.4 µg/m³, 1.6× usualOdessa, 16 March: 3.6 µg/m³, 0.5× usualOdessa, 17 March: no readingOdessa, 18 March: 98.5 µg/m³, 15× usualOdessa, 19 March: 19.0 µg/m³, 2.8× usualOdessa, 20 March: 5.9 µg/m³, 0.9× usualOdessa, 21 March: 9.2 µg/m³, 1.4× usualSocorroSocorro, 15 March: 6.5 µg/m³, 0.8× usualSocorro, 16 March: 5.5 µg/m³, 0.7× usualSocorro, 17 March: 12.0 µg/m³, 1.4× usualSocorro, 18 March: 92.5 µg/m³, 11× usualSocorro, 19 March: 4.2 µg/m³, 0.5× usualSocorro, 20 March: 11.1 µg/m³, 1.3× usualSocorro, 21 March: 14.1 µg/m³, 1.7× usualLubbockLubbock, 15 March: 3.8 µg/m³, 0.8× usualLubbock, 16 March: 1.8 µg/m³, 0.4× usualLubbock, 17 March: 8.7 µg/m³, 1.7× usualLubbock, 18 March: 77.8 µg/m³, 16× usualLubbock, 19 March: 12.2 µg/m³, 2.4× usualLubbock, 20 March: 3.5 µg/m³, 0.7× usualLubbock, 21 March: 3.5 µg/m³, 0.7× usualAlbuquerqueAlbuquerque, 15 March: 2.1 µg/m³, 0.4× usualAlbuquerque, 16 March: 3.4 µg/m³, 0.7× usualAlbuquerque, 17 March: 6.0 µg/m³, 1.2× usualAlbuquerque, 18 March: 25.5 µg/m³, 5.1× usualAlbuquerque, 19 March: 3.5 µg/m³, 0.7× usualAlbuquerque, 20 March: 6.4 µg/m³, 1.3× usualAlbuquerque, 21 March: 7.5 µg/m³, 1.5× usual15 Mar161718192021
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
Sunland ParkNew Mexico, United States1 204.018 March6.034×
El PasoTexas, United States1 230.018 March8.826×
Las CrucesNew Mexico, United States1 112.018 March3.722×
HobbsNew Mexico, United States1 105.018 March5.918×
LubbockTexas, United States1 77.818 March4.216×
OdessaTexas, United States1 98.518 March6.715×
Ciudad JuárezChihuahua, Mexico1 187.518 March15.013×
SocorroTexas, United States1 92.518 March8.411×
AlbuquerqueNew Mexico, United States1 25.518 March4.75.1×

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 84 of 106 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 106.

Use this page

SmogRank, South-western United States, March 2025: 9 cities with PM2.5 at twice their usual or more, 18 March 2025, smogrank.com/episodes/2025-03-south-western-united-states (accessed 2 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.