SmogRank / Episodes / United States
California, United States, 21 to 23 January 2026
For 3 days, from 21 to 23 January 2026, 19 cities in the United States had PM2.5 at least twice their usual for the time of year. The worst reading was Riverside, California, United States: 54.2 µg/m³ on 22 January, about 6.9× its usual 7.9.
No cause named We have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached 19 in 1 country
Days 3 21 to 23 January 2026
Worst day 21 January 15 cities counted
Furthest above usual 8.8× Pasadena
Day by day
Play 21 January 15 cities at twice their usual or more
Mission Viejo Oceanside Lake Elsinore Temecula Poway Burbank La Crescenta-Montrose El Cajon Chula Vista Banning Tijuana Agoura Santa Clarita Thousand Oaks Simi Valley Lancaster Fillmore Oxnard Indio Santa Barbara Ridgecrest Goleta Brawley El Centro Bakersfield Calexico Mexicali Delano Lompoc Orcutt Nipomo Yuma Arroyo Grande San Luis Obispo Atascadero Imperial Beach Hawthorne Compton Los Angeles Carson Torrance Long Beach San Diego Inglewood Lomita Anaheim Whittier Santa Monica Jurupa Valley Huntington Beach Fontana Glendora Riverside Pasadena 18 Jan 19 20 21 22 23 24 25 26 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
Huntington Beach Huntington Beach, 18 January: 24.0 µg/m³ Huntington Beach, 19 January: 19.1 µg/m³ Huntington Beach, 20 January: 30.8 µg/m³ Huntington Beach, 21 January: 50.9 µg/m³, 5.7× its usual 8.9 Huntington Beach, 22 January: 40.7 µg/m³, 4.6× its usual 8.9 Huntington Beach, 23 January: 21.1 µg/m³ Huntington Beach, 24 January: 7.6 µg/m³ Huntington Beach, 25 January: 18.8 µg/m³ Huntington Beach, 26 January: 14.3 µg/m³ Whittier Whittier, 18 January: 13.6 µg/m³ Whittier, 19 January: 22.0 µg/m³ Whittier, 20 January: 20.2 µg/m³ Whittier, 21 January: 49.4 µg/m³, 4.5× its usual 11.1 Whittier, 22 January: 46.2 µg/m³, 4.2× its usual 11.1 Whittier, 23 January: 18.9 µg/m³ Whittier, 24 January: 13.6 µg/m³ Whittier, 25 January: 27.1 µg/m³ Whittier, 26 January: 7.2 µg/m³ Anaheim Anaheim, 18 January: 10.7 µg/m³ Anaheim, 19 January: 12.4 µg/m³ Anaheim, 20 January: 16.2 µg/m³ Anaheim, 21 January: 33.4 µg/m³, 4.4× its usual 7.6 Anaheim, 22 January: 30.8 µg/m³, 4.1× its usual 7.5 Anaheim, 23 January: 16.1 µg/m³ Anaheim, 24 January: 8.6 µg/m³ Anaheim, 25 January: 10.6 µg/m³ Anaheim, 26 January: 8.1 µg/m³ Pasadena Pasadena, 18 January: 1.1 µg/m³ Pasadena, 19 January: 4.7 µg/m³ Pasadena, 20 January: 2.1 µg/m³ Pasadena, 21 January: 32.2 µg/m³, 6.4× its usual 2.3 Pasadena, 22 January: 43.8 µg/m³, 8.8× its usual 1.9 Pasadena, 23 January: 38.9 µg/m³, 7.8× its usual 1.9 Pasadena, 24 January: 21.0 µg/m³ Pasadena, 25 January: 3.8 µg/m³ Pasadena, 26 January: 0.3 µg/m³ Compton Compton, 18 January: 13.0 µg/m³ Compton, 19 January: 18.1 µg/m³ Compton, 20 January: 17.4 µg/m³ Compton, 21 January: 32.0 µg/m³, 2.4× its usual 13.3 Compton, 22 January: 18.1 µg/m³ Compton, 23 January: 10.6 µg/m³ Compton, 24 January: 11.2 µg/m³ Compton, 25 January: 17.0 µg/m³ Compton, 26 January: 12.2 µg/m³ Imperial Beach Imperial Beach, 18 January: 15.0 µg/m³ Imperial Beach, 19 January: 26.3 µg/m³ Imperial Beach, 20 January: 25.4 µg/m³ Imperial Beach, 21 January: 29.5 µg/m³, 2.1× its usual 14.3 Imperial Beach, 22 January: 31.0 µg/m³, 2.2× its usual 14.1 Imperial Beach, 23 January: 13.5 µg/m³ Imperial Beach, 24 January: 7.2 µg/m³ Imperial Beach, 25 January: 17.9 µg/m³ Imperial Beach, 26 January: 10.9 µg/m³ Inglewood Inglewood, 18 January: 5.5 µg/m³ Inglewood, 19 January: 17.5 µg/m³ Inglewood, 20 January: 18.3 µg/m³ Inglewood, 21 January: 29.3 µg/m³, 3.9× its usual 7.5 Inglewood, 22 January: 20.2 µg/m³ Inglewood, 23 January: 16.8 µg/m³ Inglewood, 24 January: 7.4 µg/m³ Inglewood, 25 January: 11.9 µg/m³ Inglewood, 26 January: 9.2 µg/m³ Long Beach Long Beach, 18 January: 9.7 µg/m³ Long Beach, 19 January: 14.1 µg/m³ Long Beach, 20 January: 19.7 µg/m³ Long Beach, 21 January: 28.2 µg/m³, 3.1× its usual 9.0 Long Beach, 22 January: 14.2 µg/m³ Long Beach, 23 January: 9.8 µg/m³ Long Beach, 24 January: 8.0 µg/m³ Long Beach, 25 January: 13.3 µg/m³ Long Beach, 26 January: 12.5 µg/m³ Carson Carson, 18 January: 9.0 µg/m³ Carson, 19 January: 16.3 µg/m³ Carson, 20 January: 24.9 µg/m³ Carson, 21 January: 27.9 µg/m³, 2.8× its usual 9.8 Carson, 22 January: 20.4 µg/m³ Carson, 23 January: 14.4 µg/m³ Carson, 24 January: 6.7 µg/m³ Carson, 25 January: 13.2 µg/m³ Carson, 26 January: 11.1 µg/m³ Hawthorne Hawthorne, 18 January: 11.0 µg/m³ Hawthorne, 19 January: 20.6 µg/m³ Hawthorne, 20 January: 27.5 µg/m³ Hawthorne, 21 January: 26.9 µg/m³, 2.4× its usual 11.0 Hawthorne, 22 January: 20.0 µg/m³ Hawthorne, 23 January: 16.0 µg/m³ Hawthorne, 24 January: 7.9 µg/m³ Hawthorne, 25 January: 15.6 µg/m³ Hawthorne, 26 January: 11.6 µg/m³ Torrance Torrance, 18 January: 7.5 µg/m³ Torrance, 19 January: 16.6 µg/m³ Torrance, 20 January: 22.2 µg/m³ Torrance, 21 January: 26.1 µg/m³, 3.0× its usual 8.6 Torrance, 22 January: 18.9 µg/m³ Torrance, 23 January: 12.5 µg/m³ Torrance, 24 January: 6.0 µg/m³ Torrance, 25 January: 11.6 µg/m³ Torrance, 26 January: 9.0 µg/m³ Los Angeles Los Angeles, 18 January: 7.4 µg/m³ Los Angeles, 19 January: 14.8 µg/m³ Los Angeles, 20 January: 11.5 µg/m³ Los Angeles, 21 January: 26.1 µg/m³, 2.7× its usual 9.5 Los Angeles, 22 January: 16.4 µg/m³ Los Angeles, 23 January: 13.2 µg/m³ Los Angeles, 24 January: 8.9 µg/m³ Los Angeles, 25 January: 8.8 µg/m³ Los Angeles, 26 January: 7.2 µg/m³ Lomita Lomita, 18 January: 5.2 µg/m³ Lomita, 19 January: 9.0 µg/m³ Lomita, 20 January: 14.6 µg/m³ Lomita, 21 January: 25.5 µg/m³, 4.0× its usual 6.4 Lomita, 22 January: 17.5 µg/m³ Lomita, 23 January: 9.6 µg/m³ Lomita, 24 January: 6.1 µg/m³ Lomita, 25 January: 8.4 µg/m³ Lomita, 26 January: 7.0 µg/m³ San Diego San Diego, 18 January: 7.6 µg/m³ San Diego, 19 January: 9.5 µg/m³ San Diego, 20 January: 18.0 µg/m³ San Diego, 21 January: 25.3 µg/m³, 3.2× its usual 7.9 San Diego, 22 January: 24.0 µg/m³ San Diego, 23 January: 14.2 µg/m³ San Diego, 24 January: 6.9 µg/m³ San Diego, 25 January: 8.6 µg/m³ San Diego, 26 January: 6.2 µg/m³ Santa Monica Santa Monica, 18 January: 4.1 µg/m³ Santa Monica, 19 January: 10.8 µg/m³ Santa Monica, 20 January: 11.0 µg/m³ Santa Monica, 21 January: 25.2 µg/m³, 4.8× its usual 5.3 Santa Monica, 22 January: 19.4 µg/m³ Santa Monica, 23 January: 15.2 µg/m³ Santa Monica, 24 January: 6.6 µg/m³ Santa Monica, 25 January: 5.9 µg/m³ Santa Monica, 26 January: 5.1 µg/m³ Riverside Riverside, 18 January: 9.4 µg/m³ Riverside, 19 January: 10.2 µg/m³ Riverside, 20 January: 11.1 µg/m³ Riverside, 21 January: 23.5 µg/m³ Riverside, 22 January: 54.2 µg/m³, 6.9× its usual 7.9 Riverside, 23 January: 41.1 µg/m³, 5.2× its usual 7.9 Riverside, 24 January: 16.2 µg/m³ Riverside, 25 January: 13.5 µg/m³ Riverside, 26 January: 9.1 µg/m³ Jurupa Valley Jurupa Valley, 18 January: 17.5 µg/m³ Jurupa Valley, 19 January: 18.9 µg/m³ Jurupa Valley, 20 January: 13.6 µg/m³ Jurupa Valley, 21 January: 24.0 µg/m³ Jurupa Valley, 22 January: 48.5 µg/m³, 4.9× its usual 9.8 Jurupa Valley, 23 January: 30.3 µg/m³, 3.1× its usual 9.9 Jurupa Valley, 24 January: 13.8 µg/m³ Jurupa Valley, 25 January: 16.0 µg/m³ Jurupa Valley, 26 January: 12.3 µg/m³ Fontana Fontana, 18 January: 8.3 µg/m³ Fontana, 19 January: 10.4 µg/m³ Fontana, 20 January: 11.0 µg/m³ Fontana, 21 January: 19.4 µg/m³ Fontana, 22 January: 44.7 µg/m³, 6.1× its usual 7.3 Fontana, 23 January: 30.2 µg/m³, 4.3× its usual 7.0 Fontana, 24 January: 10.3 µg/m³ Fontana, 25 January: 6.9 µg/m³ Fontana, 26 January: 6.8 µg/m³ Glendora Glendora, 18 January: 2.3 µg/m³ Glendora, 19 January: 4.2 µg/m³ Glendora, 20 January: 2.7 µg/m³ Glendora, 21 January: 20.7 µg/m³ Glendora, 22 January: 34.3 µg/m³, 6.9× its usual 4.5 Glendora, 23 January: 18.6 µg/m³ Glendora, 24 January: 8.2 µg/m³ Glendora, 25 January: 4.1 µg/m³ Glendora, 26 January: 3.4 µg/m³ 18 Jan 19 20 21 22 23 24 25 26 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
Pasadena California, United States 3 22 January 1.9 8.8× Riverside California, United States 2 22 January 7.9 6.9× Glendora California, United States 1 22 January 4.5 6.9× Fontana California, United States 2 22 January 7.3 6.1× Huntington Beach California, United States 2 21 January 8.9 5.7× Jurupa Valley California, United States 2 22 January 9.8 4.9× Santa Monica California, United States 1 21 January 5.3 4.8× Whittier California, United States 2 21 January 11.1 4.5× Anaheim California, United States 2 21 January 7.6 4.4× Lomita California, United States 1 21 January 6.4 4.0× Inglewood California, United States 1 21 January 7.5 3.9× San Diego California, United States 1 21 January 7.9 3.2× Long Beach California, United States 1 21 January 9.0 3.1× Torrance California, United States 1 21 January 8.6 3.0× Carson California, United States 1 21 January 9.8 2.8× Los Angeles California, United States 1 21 January 9.5 2.7× Compton California, United States 1 21 January 13.3 2.4× Hawthorne California, United States 1 21 January 11.0 2.4× Imperial Beach California, United States 2 22 January 14.1 2.2×
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
Number 56 of 130 episodes in the United States 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 California, United States, 21 to 23 January 2026 19 Bars: cities reached; colour: the level of the episode's highest daily reading. All 130 .
Use this page SmogRank, California, United States, 21 to 23 January 2026: 19 cities with PM2.5 at twice their usual or more, 21 to 23 January 2026, smogrank.com/episodes/2026-01-21-california-united-states (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.
