SmogRank / Episodes / Mexico

Southern Mexico, March 2025

For 1 day, on 20 March 2025, 8 cities in Mexico had PM2.5 at least twice their usual for the time of year. The worst reading was Irapuato, Guanajuato, Mexico: 58.9 µg/m³ on 20 March, about 3.2× its usual 18.5.

No cause namedWe have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached8in 1 country
Days120 March 2025
Worst day20 March8 cities counted
Furthest above usual3.2×Irapuato

Day by day

20 March 8 cities at twice their usual or more
SalamancaCelayaLeón de los AldamaMoreliaSan Luis PotosíAguascalientesTlaquepaqueZapopanSan Francisco TlalcilalcalpanHacienda Santa FeSanta AnitaTolucaXonacatlánSan Salvador TizatlalliNaucalpan de JuárezEcatepec de MorelosMexico CityPachuca de SotoCiudad NezahualcoyotlLa Providencia Siglo XXICuernavacaZacatepec de HidalgoTlaxcalaAtlixcoApizacoCholulaPueblaTepicTehuacánAbasoloSan Miguel de AllendeMixquiahuala de JuárezGuadalajaraGuanajuatoSan Luis de la PazSan Juan del RíoIrapuato
17 Mar181920212223
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

IrapuatoIrapuato, 17 March: 27.5 µg/m³Irapuato, 18 March: 31.6 µg/m³Irapuato, 19 March: 25.1 µg/m³Irapuato, 20 March: 58.9 µg/m³, 3.2× its usual 18.5Irapuato, 21 March: 32.4 µg/m³Irapuato, 22 March: 27.6 µg/m³Irapuato, 23 March: 25.5 µg/m³GuadalajaraGuadalajara, 17 March: 59.9 µg/m³Guadalajara, 18 March: 45.3 µg/m³Guadalajara, 19 March: 37.0 µg/m³Guadalajara, 20 March: 56.3 µg/m³, 2.6× its usual 21.5Guadalajara, 21 March: 49.5 µg/m³Guadalajara, 22 March: 42.7 µg/m³Guadalajara, 23 March: 35.9 µg/m³San Luis de la PazSan Luis de la Paz, 17 March: 30.1 µg/m³San Luis de la Paz, 18 March: 31.5 µg/m³San Luis de la Paz, 19 March: 33.5 µg/m³San Luis de la Paz, 20 March: 54.6 µg/m³, 2.9× its usual 19.1San Luis de la Paz, 21 March: 27.3 µg/m³San Luis de la Paz, 22 March: 28.1 µg/m³San Luis de la Paz, 23 March: 26.7 µg/m³San Juan del RíoSan Juan del Río, 17 March: 18.9 µg/m³San Juan del Río, 18 March: 22.6 µg/m³San Juan del Río, 19 March: 29.3 µg/m³San Juan del Río, 20 March: 50.8 µg/m³, 3.2× its usual 15.9San Juan del Río, 21 March: 22.2 µg/m³San Juan del Río, 22 March: 27.4 µg/m³San Juan del Río, 23 March: 22.5 µg/m³Mixquiahuala de Juá…Mixquiahuala de Juárez, 17 March: 24.6 µg/m³Mixquiahuala de Juárez, 18 March: 27.8 µg/m³Mixquiahuala de Juárez, 19 March: 30.7 µg/m³Mixquiahuala de Juárez, 20 March: 48.6 µg/m³, 2.3× its usual 20.8Mixquiahuala de Juárez, 21 March: 23.6 µg/m³Mixquiahuala de Juárez, 22 March: 25.1 µg/m³Mixquiahuala de Juárez, 23 March: 22.2 µg/m³GuanajuatoGuanajuato, 17 March: 16.7 µg/m³Guanajuato, 18 March: 18.0 µg/m³Guanajuato, 19 March: 17.6 µg/m³Guanajuato, 20 March: 41.4 µg/m³, 2.9× its usual 14.2Guanajuato, 21 March: 28.1 µg/m³Guanajuato, 22 March: 23.5 µg/m³Guanajuato, 23 March: 19.5 µg/m³San Miguel de Allen…San Miguel de Allende, 17 March: 20.9 µg/m³San Miguel de Allende, 18 March: 19.6 µg/m³San Miguel de Allende, 19 March: 16.8 µg/m³San Miguel de Allende, 20 March: 33.9 µg/m³, 2.3× its usual 14.5San Miguel de Allende, 21 March: 22.9 µg/m³San Miguel de Allende, 22 March: 21.1 µg/m³San Miguel de Allende, 23 March: 17.5 µg/m³AbasoloAbasolo, 17 March: 15.8 µg/m³Abasolo, 18 March: 22.1 µg/m³Abasolo, 19 March: 14.3 µg/m³Abasolo, 20 March: 31.9 µg/m³, 2.3× its usual 13.9Abasolo, 21 March: 14.5 µg/m³Abasolo, 22 March: 16.8 µg/m³Abasolo, 23 March: 17.1 µg/m³17 Mar181920212223
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
IrapuatoGuanajuato, Mexico1 58.920 March18.53.2×
San Juan del RíoQuerétaro, Mexico1 50.820 March15.93.2×
San Luis de la PazGuanajuato, Mexico1 54.620 March19.12.9×
GuanajuatoGuanajuato, Mexico1 41.420 March14.22.9×
GuadalajaraJalisco, Mexico1 56.320 March21.52.6×
Mixquiahuala de JuárezHidalgo, Mexico1 48.620 March20.82.3×
San Miguel de AllendeGuanajuato, Mexico1 33.920 March14.52.3×
AbasoloGuanajuato, Mexico1 31.920 March13.92.3×

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 Mexico

Number 13 of 16 episodes in Mexico since our records began, by cities reached.

Bars: cities reached; colour: the level of the episode's highest daily reading. All 16.

Use this page

SmogRank, Southern Mexico, March 2025: 8 cities with PM2.5 at twice their usual or more, 20 March 2025, smogrank.com/episodes/2025-03-southern-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.