SmogRank / Episodes / United States

California and Oregon, United States, December 2024

For 11 days, from 1 to 11 December 2024, 61 cities in the United States had PM2.5 at least twice their usual for the time of year. The worst reading was Visalia, California, United States: 64.8 µg/m³ on 4 December, about 3.8× its usual 17.0.

No cause namedWe have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached61in 1 country
Days111 to 11 December 2024
Worst day5 December37 cities counted
Furthest above usual5.2×Fontana

Day by day

5 December 37 cities at twice their usual or more
South Lake TahoeCarson CityTruckeeRenoSpanish SpringsTracyHollisterFolsomRidgecrestGilroyAtascaderoLincolnPrunedaleSalinasSan Luis ObispoWatsonvilleArroyo GrandeNipomoDavisSeasideLive OakSunnyvaleOrcuttSanta CruzLancasterRedwood CityFillmoreSanta BarbaraGoletaLompocSanta PaulaSanta ClaritaSimi ValleyOxnardThousand OaksParadiseVictorvilleGlendoraSanta RosaWindsorSummerlin SouthSpring ValleyEnterpriseBanningLas VegasUkiahHendersonTemeculaReddingBoulder CityIndioPowayMesquiteBrawleyAshlandEl CentroGrants PassYumaTwin FallsCalexicoComptonHawthorneImperial BeachAltamontLong BeachModestoEl CajonRosevilleMedfordStocktonCarsonTorranceArden-ArcadeAnaheimFlorinYuba CityChicoInglewoodSan JoseOceansideGaltChula VistaRichmondBerkeleyFresnoBakersfieldHanfordMaderaTurlockLomitaSan DiegoMantecaCorcoranLivermoreVacavilleSacramentoOaklandSouth San FranciscoSan FranciscoWoodlandVisaliaMercedPleasantonSanta MonicaLos AngelesJurupa ValleyLa Crescenta-MontroseSan RafaelBurbankClovisConcordSan LeandroRiversidePalo AltoLake ElsinoreVallejoAgouraMartinezPortervilleFontana
28 Nov1 Dec47101314
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

VisaliaVisalia, 28 November: 21.7 µg/m³Visalia, 29 November: 20.4 µg/m³Visalia, 30 November: 22.4 µg/m³Visalia, 1 December: 39.8 µg/m³, 2.3× its usual 17.4Visalia, 2 December: 41.0 µg/m³, 2.4× its usual 17.4Visalia, 3 December: 58.3 µg/m³, 3.4× its usual 17.3Visalia, 4 December: 64.8 µg/m³, 3.8× its usual 17.0Visalia, 5 December: 62.2 µg/m³, 3.7× its usual 16.8Visalia, 6 December: no readingVisalia, 7 December: no readingVisalia, 8 December: no readingVisalia, 9 December: no readingVisalia, 10 December: no readingVisalia, 11 December: no readingVisalia, 12 December: no readingVisalia, 13 December: 14.1 µg/m³Visalia, 14 December: no readingBakersfieldBakersfield, 28 November: 17.1 µg/m³Bakersfield, 29 November: 24.0 µg/m³Bakersfield, 30 November: 36.8 µg/m³Bakersfield, 1 December: 44.4 µg/m³, 2.3× its usual 19.4Bakersfield, 2 December: 49.7 µg/m³, 2.6× its usual 19.2Bakersfield, 3 December: 49.5 µg/m³, 2.6× its usual 18.9Bakersfield, 4 December: 52.2 µg/m³, 2.8× its usual 18.5Bakersfield, 5 December: 57.7 µg/m³, 3.1× its usual 18.4Bakersfield, 6 December: 59.5 µg/m³, 3.3× its usual 18.3Bakersfield, 7 December: 61.0 µg/m³, 3.3× its usual 18.4Bakersfield, 8 December: 58.8 µg/m³, 3.2× its usual 18.4Bakersfield, 9 December: 45.6 µg/m³, 2.5× its usual 18.5Bakersfield, 10 December: 26.6 µg/m³Bakersfield, 11 December: 34.9 µg/m³Bakersfield, 12 December: 25.2 µg/m³Bakersfield, 13 December: 14.6 µg/m³Bakersfield, 14 December: 6.7 µg/m³PortervillePorterville, 28 November: 17.1 µg/m³Porterville, 29 November: 16.1 µg/m³Porterville, 30 November: 21.7 µg/m³Porterville, 1 December: 34.2 µg/m³, 2.9× its usual 11.8Porterville, 2 December: 36.8 µg/m³, 3.1× its usual 11.7Porterville, 3 December: 47.0 µg/m³, 4.2× its usual 11.3Porterville, 4 December: 45.2 µg/m³, 4.0× its usual 11.2Porterville, 5 December: 51.5 µg/m³, 4.6× its usual 11.2Porterville, 6 December: 54.8 µg/m³, 4.9× its usual 11.2Porterville, 7 December: 53.2 µg/m³, 4.8× its usual 11.2Porterville, 8 December: 54.2 µg/m³, 4.8× its usual 11.2Porterville, 9 December: 33.1 µg/m³, 3.0× its usual 11.2Porterville, 10 December: 20.9 µg/m³Porterville, 11 December: 22.2 µg/m³Porterville, 12 December: 11.9 µg/m³Porterville, 13 December: 9.0 µg/m³Porterville, 14 December: 6.7 µg/m³HanfordHanford, 28 November: 14.5 µg/m³Hanford, 29 November: 19.5 µg/m³Hanford, 30 November: 26.9 µg/m³Hanford, 1 December: 34.6 µg/m³, 2.0× its usual 17.1Hanford, 2 December: 40.0 µg/m³, 2.3× its usual 17.1Hanford, 3 December: 47.5 µg/m³, 2.9× its usual 16.5Hanford, 4 December: 52.3 µg/m³, 3.2× its usual 16.2Hanford, 5 December: 53.8 µg/m³, 3.4× its usual 16.0Hanford, 6 December: 49.0 µg/m³, 3.2× its usual 15.5Hanford, 7 December: 45.0 µg/m³, 2.9× its usual 15.5Hanford, 8 December: 38.5 µg/m³, 2.4× its usual 15.8Hanford, 9 December: 31.8 µg/m³, 2.1× its usual 15.5Hanford, 10 December: 32.0 µg/m³Hanford, 11 December: 31.7 µg/m³Hanford, 12 December: 21.1 µg/m³Hanford, 13 December: 16.0 µg/m³Hanford, 14 December: 6.4 µg/m³TurlockTurlock, 28 November: 16.2 µg/m³Turlock, 29 November: 24.4 µg/m³Turlock, 30 November: 22.4 µg/m³Turlock, 1 December: 29.7 µg/m³, 2.0× its usual 14.7Turlock, 2 December: 23.0 µg/m³Turlock, 3 December: 32.0 µg/m³, 2.4× its usual 13.6Turlock, 4 December: 36.8 µg/m³, 2.7× its usual 13.4Turlock, 5 December: 40.1 µg/m³, 3.0× its usual 13.3Turlock, 6 December: 42.1 µg/m³, 3.2× its usual 13.2Turlock, 7 December: 46.5 µg/m³, 3.5× its usual 13.4Turlock, 8 December: 31.1 µg/m³, 2.3× its usual 13.4Turlock, 9 December: 18.8 µg/m³Turlock, 10 December: 27.3 µg/m³, 2.0× its usual 13.7Turlock, 11 December: 27.9 µg/m³, 2.0× its usual 13.7Turlock, 12 December: 21.7 µg/m³Turlock, 13 December: 13.6 µg/m³Turlock, 14 December: 4.9 µg/m³FlorinFlorin, 28 November: 19.3 µg/m³Florin, 29 November: 26.9 µg/m³Florin, 30 November: 32.8 µg/m³Florin, 1 December: 32.5 µg/m³, 2.2× its usual 15.0Florin, 2 December: 32.5 µg/m³, 2.2× its usual 15.0Florin, 3 December: 30.5 µg/m³, 2.2× its usual 14.0Florin, 4 December: 28.4 µg/m³, 2.1× its usual 13.4Florin, 5 December: 28.6 µg/m³, 2.2× its usual 12.8Florin, 6 December: 34.0 µg/m³, 2.6× its usual 12.9Florin, 7 December: 44.1 µg/m³, 3.0× its usual 14.5Florin, 8 December: 30.4 µg/m³, 2.0× its usual 15.1Florin, 9 December: 21.2 µg/m³Florin, 10 December: 29.8 µg/m³Florin, 11 December: 37.8 µg/m³, 2.3× its usual 16.3Florin, 12 December: 26.7 µg/m³Florin, 13 December: 12.9 µg/m³Florin, 14 December: 1.7 µg/m³MantecaManteca, 28 November: 14.5 µg/m³Manteca, 29 November: 18.1 µg/m³Manteca, 30 November: 24.0 µg/m³Manteca, 1 December: 30.2 µg/m³, 2.4× its usual 12.7Manteca, 2 December: 19.4 µg/m³Manteca, 3 December: 30.9 µg/m³, 2.5× its usual 12.4Manteca, 4 December: 31.1 µg/m³, 2.5× its usual 12.3Manteca, 5 December: 34.5 µg/m³, 2.9× its usual 11.9Manteca, 6 December: 35.4 µg/m³, 3.0× its usual 11.9Manteca, 7 December: 44.0 µg/m³, 3.6× its usual 12.3Manteca, 8 December: 25.1 µg/m³, 2.0× its usual 12.4Manteca, 9 December: 18.2 µg/m³Manteca, 10 December: 28.3 µg/m³, 2.3× its usual 12.4Manteca, 11 December: 33.6 µg/m³, 2.7× its usual 12.4Manteca, 12 December: 25.7 µg/m³Manteca, 13 December: 11.3 µg/m³Manteca, 14 December: 6.8 µg/m³ModestoModesto, 28 November: 13.4 µg/m³Modesto, 29 November: 29.7 µg/m³Modesto, 30 November: 24.0 µg/m³Modesto, 1 December: 34.0 µg/m³, 2.2× its usual 15.2Modesto, 2 December: 25.5 µg/m³Modesto, 3 December: 33.1 µg/m³, 2.2× its usual 14.8Modesto, 4 December: 38.8 µg/m³, 2.6× its usual 14.7Modesto, 5 December: 36.4 µg/m³, 2.5× its usual 14.6Modesto, 6 December: no readingModesto, 7 December: no readingModesto, 8 December: no readingModesto, 9 December: no readingModesto, 10 December: no readingModesto, 11 December: no readingModesto, 12 December: no readingModesto, 13 December: 11.2 µg/m³Modesto, 14 December: no readingChicoChico, 28 November: 29.3 µg/m³Chico, 29 November: 24.1 µg/m³Chico, 30 November: 20.3 µg/m³Chico, 1 December: 28.1 µg/m³, 3.0× its usual 9.4Chico, 2 December: 25.8 µg/m³, 2.8× its usual 9.1Chico, 3 December: 24.4 µg/m³Chico, 4 December: 27.2 µg/m³, 3.0× its usual 9.0Chico, 5 December: 25.0 µg/m³, 2.8× its usual 9.0Chico, 6 December: 24.1 µg/m³Chico, 7 December: 28.3 µg/m³, 3.1× its usual 9.0Chico, 8 December: 10.8 µg/m³Chico, 9 December: 11.7 µg/m³Chico, 10 December: 24.4 µg/m³Chico, 11 December: 22.5 µg/m³Chico, 12 December: 9.1 µg/m³Chico, 13 December: 3.5 µg/m³Chico, 14 December: 3.7 µg/m³RosevilleRoseville, 28 November: 9.7 µg/m³Roseville, 29 November: 13.5 µg/m³Roseville, 30 November: 19.7 µg/m³Roseville, 1 December: 26.3 µg/m³, 2.7× its usual 9.7Roseville, 2 December: 19.1 µg/m³Roseville, 3 December: 17.1 µg/m³Roseville, 4 December: 14.1 µg/m³Roseville, 5 December: 14.8 µg/m³Roseville, 6 December: no readingRoseville, 7 December: no readingRoseville, 8 December: no readingRoseville, 9 December: no readingRoseville, 10 December: no readingRoseville, 11 December: no readingRoseville, 12 December: no readingRoseville, 13 December: 3.8 µg/m³Roseville, 14 December: no readingJurupa ValleyJurupa Valley, 28 November: 7.0 µg/m³Jurupa Valley, 29 November: 8.1 µg/m³Jurupa Valley, 30 November: 13.5 µg/m³Jurupa Valley, 1 December: 21.0 µg/m³Jurupa Valley, 2 December: 29.7 µg/m³, 2.1× its usual 14.4Jurupa Valley, 3 December: 33.1 µg/m³, 2.3× its usual 14.4Jurupa Valley, 4 December: 42.4 µg/m³, 2.9× its usual 14.4Jurupa Valley, 5 December: 58.0 µg/m³, 4.0× its usual 14.6Jurupa Valley, 6 December: 21.2 µg/m³Jurupa Valley, 7 December: 14.3 µg/m³Jurupa Valley, 8 December: 23.9 µg/m³Jurupa Valley, 9 December: 21.4 µg/m³Jurupa Valley, 10 December: 4.0 µg/m³Jurupa Valley, 11 December: 11.6 µg/m³Jurupa Valley, 12 December: 14.4 µg/m³Jurupa Valley, 13 December: 16.4 µg/m³Jurupa Valley, 14 December: 20.2 µg/m³FresnoFresno, 28 November: 17.8 µg/m³Fresno, 29 November: 20.7 µg/m³Fresno, 30 November: 23.7 µg/m³Fresno, 1 December: 31.3 µg/m³Fresno, 2 December: 38.4 µg/m³, 2.1× its usual 18.3Fresno, 3 December: 44.8 µg/m³, 2.5× its usual 18.1Fresno, 4 December: 49.0 µg/m³, 2.7× its usual 18.1Fresno, 5 December: 54.9 µg/m³, 3.1× its usual 17.9Fresno, 6 December: 57.1 µg/m³, 3.2× its usual 18.0Fresno, 7 December: 54.5 µg/m³, 3.0× its usual 18.3Fresno, 8 December: 42.8 µg/m³, 2.3× its usual 18.3Fresno, 9 December: 39.2 µg/m³, 2.1× its usual 18.3Fresno, 10 December: 32.3 µg/m³Fresno, 11 December: 36.7 µg/m³Fresno, 12 December: 20.7 µg/m³Fresno, 13 December: 9.5 µg/m³Fresno, 14 December: 4.4 µg/m³ClovisClovis, 28 November: 14.6 µg/m³Clovis, 29 November: 16.0 µg/m³Clovis, 30 November: 20.2 µg/m³Clovis, 1 December: 24.7 µg/m³Clovis, 2 December: 28.7 µg/m³, 2.4× its usual 12.1Clovis, 3 December: 40.1 µg/m³, 3.5× its usual 11.6Clovis, 4 December: 40.4 µg/m³, 3.5× its usual 11.5Clovis, 5 December: 46.4 µg/m³, 4.0× its usual 11.6Clovis, 6 December: 51.3 µg/m³, 4.2× its usual 12.1Clovis, 7 December: 49.7 µg/m³, 4.1× its usual 12.2Clovis, 8 December: 41.0 µg/m³, 3.4× its usual 12.1Clovis, 9 December: 43.4 µg/m³, 3.6× its usual 12.2Clovis, 10 December: 32.6 µg/m³, 2.5× its usual 12.9Clovis, 11 December: 29.2 µg/m³, 2.2× its usual 13.2Clovis, 12 December: 19.8 µg/m³Clovis, 13 December: 10.2 µg/m³Clovis, 14 December: 6.0 µg/m³SacramentoSacramento, 28 November: 11.9 µg/m³Sacramento, 29 November: 12.3 µg/m³Sacramento, 30 November: 22.5 µg/m³Sacramento, 1 December: 20.6 µg/m³Sacramento, 2 December: 25.8 µg/m³, 2.6× its usual 9.9Sacramento, 3 December: 26.2 µg/m³, 2.7× its usual 9.7Sacramento, 4 December: 26.4 µg/m³, 2.8× its usual 9.6Sacramento, 5 December: 24.1 µg/m³Sacramento, 6 December: 24.9 µg/m³Sacramento, 7 December: 35.3 µg/m³, 3.7× its usual 9.6Sacramento, 8 December: 17.0 µg/m³Sacramento, 9 December: 11.5 µg/m³Sacramento, 10 December: 24.4 µg/m³Sacramento, 11 December: 26.2 µg/m³, 2.6× its usual 9.9Sacramento, 12 December: 16.1 µg/m³Sacramento, 13 December: 5.0 µg/m³Sacramento, 14 December: 3.8 µg/m³MedfordMedford, 28 November: 20.1 µg/m³Medford, 29 November: 16.6 µg/m³Medford, 30 November: 15.3 µg/m³Medford, 1 December: 17.3 µg/m³Medford, 2 December: 27.7 µg/m³, 2.3× its usual 11.8Medford, 3 December: 30.3 µg/m³Medford, 4 December: 30.8 µg/m³, 2.7× its usual 11.6Medford, 5 December: 24.8 µg/m³Medford, 6 December: 24.7 µg/m³Medford, 7 December: 21.1 µg/m³Medford, 8 December: 9.4 µg/m³Medford, 9 December: 16.3 µg/m³Medford, 10 December: 24.6 µg/m³Medford, 11 December: 20.0 µg/m³Medford, 12 December: 8.1 µg/m³Medford, 13 December: 8.5 µg/m³Medford, 14 December: 5.1 µg/m³RiversideRiverside, 28 November: 4.2 µg/m³Riverside, 29 November: 3.8 µg/m³Riverside, 30 November: 7.3 µg/m³Riverside, 1 December: 13.2 µg/m³Riverside, 2 December: 23.2 µg/m³Riverside, 3 December: 25.2 µg/m³, 2.1× its usual 11.8Riverside, 4 December: 35.8 µg/m³, 3.0× its usual 12.1Riverside, 5 December: 53.5 µg/m³, 4.4× its usual 12.2Riverside, 6 December: 16.6 µg/m³Riverside, 7 December: 11.9 µg/m³Riverside, 8 December: 16.3 µg/m³Riverside, 9 December: 18.0 µg/m³Riverside, 10 December: 3.3 µg/m³Riverside, 11 December: 6.2 µg/m³Riverside, 12 December: 11.3 µg/m³Riverside, 13 December: 15.8 µg/m³Riverside, 14 December: 16.2 µg/m³FontanaFontana, 28 November: 12.9 µg/m³Fontana, 29 November: 7.6 µg/m³Fontana, 30 November: 7.8 µg/m³Fontana, 1 December: 13.7 µg/m³Fontana, 2 December: 21.5 µg/m³Fontana, 3 December: 27.6 µg/m³, 2.8× its usual 10.0Fontana, 4 December: 38.9 µg/m³, 3.9× its usual 10.0Fontana, 5 December: 51.7 µg/m³, 5.2× its usual 10.0Fontana, 6 December: 14.5 µg/m³Fontana, 7 December: 8.2 µg/m³Fontana, 8 December: 12.0 µg/m³Fontana, 9 December: 14.4 µg/m³Fontana, 10 December: 5.5 µg/m³Fontana, 11 December: 10.4 µg/m³Fontana, 12 December: 10.9 µg/m³Fontana, 13 December: 16.9 µg/m³Fontana, 14 December: 12.6 µg/m³CorcoranCorcoran, 28 November: 12.7 µg/m³Corcoran, 29 November: 17.4 µg/m³Corcoran, 30 November: 21.4 µg/m³Corcoran, 1 December: 30.0 µg/m³Corcoran, 2 December: 28.4 µg/m³Corcoran, 3 December: 34.4 µg/m³, 2.4× its usual 14.5Corcoran, 4 December: 43.5 µg/m³, 3.2× its usual 13.7Corcoran, 5 December: 48.1 µg/m³, 3.6× its usual 13.2Corcoran, 6 December: 39.7 µg/m³, 3.1× its usual 12.9Corcoran, 7 December: 40.4 µg/m³, 3.1× its usual 13.0Corcoran, 8 December: 29.3 µg/m³, 2.3× its usual 13.0Corcoran, 9 December: 26.0 µg/m³Corcoran, 10 December: 28.0 µg/m³, 2.0× its usual 14.0Corcoran, 11 December: 26.3 µg/m³Corcoran, 12 December: 17.8 µg/m³Corcoran, 13 December: 12.0 µg/m³Corcoran, 14 December: 4.9 µg/m³MaderaMadera, 28 November: 13.3 µg/m³Madera, 29 November: 19.5 µg/m³Madera, 30 November: 23.2 µg/m³Madera, 1 December: 24.8 µg/m³Madera, 2 December: 19.9 µg/m³Madera, 3 December: 33.9 µg/m³, 2.6× its usual 13.1Madera, 4 December: 35.0 µg/m³, 2.7× its usual 13.0Madera, 5 December: 41.8 µg/m³, 3.2× its usual 12.9Madera, 6 December: 44.2 µg/m³, 3.4× its usual 13.1Madera, 7 December: 46.4 µg/m³, 3.5× its usual 13.1Madera, 8 December: 38.1 µg/m³, 2.9× its usual 13.1Madera, 9 December: 33.1 µg/m³, 2.5× its usual 13.1Madera, 10 December: 30.6 µg/m³, 2.3× its usual 13.3Madera, 11 December: 25.2 µg/m³Madera, 12 December: 19.7 µg/m³Madera, 13 December: 10.4 µg/m³Madera, 14 December: 5.2 µg/m³WoodlandWoodland, 28 November: 13.7 µg/m³Woodland, 29 November: 12.5 µg/m³Woodland, 30 November: 20.8 µg/m³Woodland, 1 December: 19.0 µg/m³Woodland, 2 December: 22.5 µg/m³Woodland, 3 December: 29.7 µg/m³, 2.7× its usual 11.0Woodland, 4 December: 24.3 µg/m³Woodland, 5 December: 25.3 µg/m³, 2.3× its usual 10.9Woodland, 6 December: 33.8 µg/m³, 3.1× its usual 11.0Woodland, 7 December: 42.5 µg/m³, 3.8× its usual 11.3Woodland, 8 December: 11.8 µg/m³Woodland, 9 December: 9.4 µg/m³Woodland, 10 December: 28.5 µg/m³, 2.5× its usual 11.4Woodland, 11 December: 28.4 µg/m³, 2.5× its usual 11.5Woodland, 12 December: 22.5 µg/m³Woodland, 13 December: 9.7 µg/m³Woodland, 14 December: 6.0 µg/m³StocktonStockton, 28 November: 23.8 µg/m³Stockton, 29 November: 36.5 µg/m³Stockton, 30 November: 24.3 µg/m³Stockton, 1 December: 27.1 µg/m³Stockton, 2 December: 26.8 µg/m³Stockton, 3 December: 36.2 µg/m³, 2.5× its usual 14.4Stockton, 4 December: 39.0 µg/m³, 2.7× its usual 14.2Stockton, 5 December: 36.7 µg/m³, 2.7× its usual 13.7Stockton, 6 December: no readingStockton, 7 December: no readingStockton, 8 December: no readingStockton, 9 December: no readingStockton, 10 December: no readingStockton, 11 December: no readingStockton, 12 December: no readingStockton, 13 December: 8.5 µg/m³Stockton, 14 December: no readingArden-ArcadeArden-Arcade, 28 November: 19.6 µg/m³Arden-Arcade, 29 November: 28.4 µg/m³Arden-Arcade, 30 November: 22.3 µg/m³Arden-Arcade, 1 December: 20.8 µg/m³Arden-Arcade, 2 December: 24.0 µg/m³Arden-Arcade, 3 December: 26.8 µg/m³, 2.5× its usual 10.6Arden-Arcade, 4 December: 27.0 µg/m³, 2.6× its usual 10.5Arden-Arcade, 5 December: 20.2 µg/m³Arden-Arcade, 6 December: 24.3 µg/m³Arden-Arcade, 7 December: 31.4 µg/m³, 2.9× its usual 11.0Arden-Arcade, 8 December: 15.8 µg/m³Arden-Arcade, 9 December: 11.8 µg/m³Arden-Arcade, 10 December: 24.0 µg/m³Arden-Arcade, 11 December: 25.9 µg/m³, 2.3× its usual 11.1Arden-Arcade, 12 December: 12.5 µg/m³Arden-Arcade, 13 December: 2.3 µg/m³Arden-Arcade, 14 December: 2.8 µg/m³MercedMerced, 28 November: 13.2 µg/m³Merced, 29 November: 17.2 µg/m³Merced, 30 November: 24.3 µg/m³Merced, 1 December: 26.8 µg/m³Merced, 2 December: 22.6 µg/m³Merced, 3 December: 26.8 µg/m³Merced, 4 December: 37.4 µg/m³, 2.8× its usual 13.2Merced, 5 December: 41.3 µg/m³, 3.2× its usual 13.0Merced, 6 December: 42.5 µg/m³, 3.2× its usual 13.1Merced, 7 December: 51.5 µg/m³, 3.9× its usual 13.2Merced, 8 December: 34.4 µg/m³, 2.6× its usual 13.1Merced, 9 December: 24.0 µg/m³Merced, 10 December: 30.0 µg/m³, 2.3× its usual 13.2Merced, 11 December: 25.6 µg/m³Merced, 12 December: 19.4 µg/m³Merced, 13 December: 14.0 µg/m³Merced, 14 December: 4.4 µg/m³Los AngelesLos Angeles, 28 November: 9.1 µg/m³Los Angeles, 29 November: 9.1 µg/m³Los Angeles, 30 November: 8.7 µg/m³Los Angeles, 1 December: 16.0 µg/m³Los Angeles, 2 December: 17.7 µg/m³Los Angeles, 3 December: 23.5 µg/m³Los Angeles, 4 December: 37.7 µg/m³, 3.3× its usual 11.3Los Angeles, 5 December: 45.2 µg/m³, 4.0× its usual 11.3Los Angeles, 6 December: 29.1 µg/m³, 2.6× its usual 11.4Los Angeles, 7 December: 12.3 µg/m³Los Angeles, 8 December: 16.4 µg/m³Los Angeles, 9 December: 32.2 µg/m³, 2.7× its usual 11.8Los Angeles, 10 December: 16.7 µg/m³Los Angeles, 11 December: 7.9 µg/m³Los Angeles, 12 December: 10.5 µg/m³Los Angeles, 13 December: 15.4 µg/m³Los Angeles, 14 December: 14.1 µg/m³BurbankBurbank, 28 November: 10.7 µg/m³Burbank, 29 November: 11.9 µg/m³Burbank, 30 November: 9.2 µg/m³Burbank, 1 December: 15.6 µg/m³Burbank, 2 December: 17.6 µg/m³Burbank, 3 December: 23.6 µg/m³Burbank, 4 December: 37.0 µg/m³, 3.5× its usual 10.5Burbank, 5 December: 44.2 µg/m³, 4.2× its usual 10.5Burbank, 6 December: 22.2 µg/m³Burbank, 7 December: 9.8 µg/m³Burbank, 8 December: 20.3 µg/m³Burbank, 9 December: 31.6 µg/m³, 2.9× its usual 10.8Burbank, 10 December: 15.4 µg/m³Burbank, 11 December: 10.7 µg/m³Burbank, 12 December: 12.9 µg/m³Burbank, 13 December: 16.1 µg/m³Burbank, 14 December: 15.7 µg/m³Palo AltoPalo Alto, 28 November: 9.1 µg/m³Palo Alto, 29 November: 12.3 µg/m³Palo Alto, 30 November: 13.7 µg/m³Palo Alto, 1 December: 16.2 µg/m³Palo Alto, 2 December: 9.7 µg/m³Palo Alto, 3 December: 11.5 µg/m³Palo Alto, 4 December: 28.1 µg/m³, 4.0× its usual 7.0Palo Alto, 5 December: 26.1 µg/m³, 3.7× its usual 7.0Palo Alto, 6 December: 15.8 µg/m³Palo Alto, 7 December: 31.5 µg/m³, 3.8× its usual 8.4Palo Alto, 8 December: 27.3 µg/m³, 3.1× its usual 8.9Palo Alto, 9 December: 4.9 µg/m³Palo Alto, 10 December: 12.3 µg/m³Palo Alto, 11 December: 41.6 µg/m³, 4.5× its usual 9.2Palo Alto, 12 December: 5.8 µg/m³Palo Alto, 13 December: 2.7 µg/m³Palo Alto, 14 December: 2.6 µg/m³AnaheimAnaheim, 28 November: no readingAnaheim, 29 November: no readingAnaheim, 30 November: no readingAnaheim, 1 December: no readingAnaheim, 2 December: no readingAnaheim, 3 December: no readingAnaheim, 4 December: 27.9 µg/m³, 2.1× its usual 13.0Anaheim, 5 December: 40.2 µg/m³, 3.0× its usual 13.2Anaheim, 6 December: 31.3 µg/m³, 2.3× its usual 13.4Anaheim, 7 December: 29.1 µg/m³, 2.2× its usual 13.4Anaheim, 8 December: 14.8 µg/m³Anaheim, 9 December: 18.8 µg/m³Anaheim, 10 December: 2.2 µg/m³Anaheim, 11 December: 9.1 µg/m³Anaheim, 12 December: 10.7 µg/m³Anaheim, 13 December: 12.8 µg/m³Anaheim, 14 December: 15.2 µg/m³CarsonCarson, 28 November: 18.7 µg/m³Carson, 29 November: 9.6 µg/m³Carson, 30 November: 9.9 µg/m³Carson, 1 December: 17.0 µg/m³Carson, 2 December: 20.0 µg/m³Carson, 3 December: 20.8 µg/m³Carson, 4 December: 29.1 µg/m³, 2.4× its usual 12.1Carson, 5 December: 34.3 µg/m³, 2.8× its usual 12.4Carson, 6 December: 29.2 µg/m³, 2.3× its usual 12.6Carson, 7 December: 18.8 µg/m³Carson, 8 December: 23.3 µg/m³Carson, 9 December: 22.5 µg/m³Carson, 10 December: 19.7 µg/m³Carson, 11 December: 12.5 µg/m³Carson, 12 December: 11.4 µg/m³Carson, 13 December: 15.0 µg/m³Carson, 14 December: 14.0 µg/m³HawthorneHawthorne, 28 November: 16.5 µg/m³Hawthorne, 29 November: 7.9 µg/m³Hawthorne, 30 November: 9.9 µg/m³Hawthorne, 1 December: 18.5 µg/m³Hawthorne, 2 December: 22.3 µg/m³Hawthorne, 3 December: 23.8 µg/m³Hawthorne, 4 December: 29.7 µg/m³, 2.2× its usual 13.4Hawthorne, 5 December: 32.1 µg/m³, 2.3× its usual 13.8Hawthorne, 6 December: 32.5 µg/m³, 2.3× its usual 14.1Hawthorne, 7 December: 24.0 µg/m³Hawthorne, 8 December: 26.3 µg/m³Hawthorne, 9 December: 26.3 µg/m³Hawthorne, 10 December: 23.1 µg/m³Hawthorne, 11 December: 12.9 µg/m³Hawthorne, 12 December: 12.8 µg/m³Hawthorne, 13 December: 15.9 µg/m³Hawthorne, 14 December: 16.2 µg/m³San JoseSan Jose, 28 November: 14.1 µg/m³San Jose, 29 November: 19.0 µg/m³San Jose, 30 November: 15.2 µg/m³San Jose, 1 December: 17.8 µg/m³San Jose, 2 December: 16.1 µg/m³San Jose, 3 December: 17.6 µg/m³San Jose, 4 December: 25.3 µg/m³, 2.5× its usual 10.1San Jose, 5 December: 26.9 µg/m³, 2.6× its usual 10.3San Jose, 6 December: 20.4 µg/m³San Jose, 7 December: 24.7 µg/m³San Jose, 8 December: 32.3 µg/m³, 3.1× its usual 10.3San Jose, 9 December: 10.8 µg/m³San Jose, 10 December: 14.7 µg/m³San Jose, 11 December: 30.4 µg/m³, 2.8× its usual 11.0San Jose, 12 December: 9.7 µg/m³San Jose, 13 December: 5.3 µg/m³San Jose, 14 December: 8.7 µg/m³InglewoodInglewood, 28 November: 10.9 µg/m³Inglewood, 29 November: 5.3 µg/m³Inglewood, 30 November: 8.2 µg/m³Inglewood, 1 December: 17.9 µg/m³Inglewood, 2 December: 19.8 µg/m³Inglewood, 3 December: 21.1 µg/m³Inglewood, 4 December: 28.1 µg/m³, 2.7× its usual 10.3Inglewood, 5 December: 32.0 µg/m³, 3.1× its usual 10.4Inglewood, 6 December: 28.0 µg/m³, 2.7× its usual 10.5Inglewood, 7 December: 14.3 µg/m³Inglewood, 8 December: 19.4 µg/m³Inglewood, 9 December: 26.2 µg/m³, 2.3× its usual 11.2Inglewood, 10 December: 15.6 µg/m³Inglewood, 11 December: 10.5 µg/m³Inglewood, 12 December: 9.7 µg/m³Inglewood, 13 December: 12.9 µg/m³Inglewood, 14 December: 12.5 µg/m³Santa MonicaSanta Monica, 28 November: 6.9 µg/m³Santa Monica, 29 November: 4.1 µg/m³Santa Monica, 30 November: 4.8 µg/m³Santa Monica, 1 December: 11.7 µg/m³Santa Monica, 2 December: 12.5 µg/m³Santa Monica, 3 December: 17.4 µg/m³Santa Monica, 4 December: 27.9 µg/m³, 3.4× its usual 8.1Santa Monica, 5 December: 32.0 µg/m³, 4.0× its usual 8.0Santa Monica, 6 December: 20.3 µg/m³Santa Monica, 7 December: 8.3 µg/m³Santa Monica, 8 December: 14.9 µg/m³Santa Monica, 9 December: 27.6 µg/m³, 3.3× its usual 8.4Santa Monica, 10 December: 6.9 µg/m³Santa Monica, 11 December: 8.6 µg/m³Santa Monica, 12 December: 8.1 µg/m³Santa Monica, 13 December: 10.4 µg/m³Santa Monica, 14 December: 8.4 µg/m³TorranceTorrance, 28 November: 16.6 µg/m³Torrance, 29 November: 8.5 µg/m³Torrance, 30 November: 9.8 µg/m³Torrance, 1 December: 15.5 µg/m³Torrance, 2 December: 16.9 µg/m³Torrance, 3 December: 18.9 µg/m³Torrance, 4 December: 28.9 µg/m³, 2.7× its usual 10.8Torrance, 5 December: 31.3 µg/m³, 2.9× its usual 10.8Torrance, 6 December: 28.9 µg/m³, 2.6× its usual 11.0Torrance, 7 December: 14.4 µg/m³Torrance, 8 December: 19.8 µg/m³Torrance, 9 December: 20.8 µg/m³Torrance, 10 December: 14.6 µg/m³Torrance, 11 December: 11.6 µg/m³Torrance, 12 December: 10.2 µg/m³Torrance, 13 December: 12.9 µg/m³Torrance, 14 December: 11.0 µg/m³AgouraAgoura, 28 November: 5.0 µg/m³Agoura, 29 November: 6.8 µg/m³Agoura, 30 November: 6.3 µg/m³Agoura, 1 December: 7.3 µg/m³Agoura, 2 December: 7.7 µg/m³Agoura, 3 December: 13.7 µg/m³Agoura, 4 December: 29.6 µg/m³, 4.9× its usual 6.1Agoura, 5 December: 27.7 µg/m³, 4.5× its usual 6.2Agoura, 6 December: 4.8 µg/m³Agoura, 7 December: 5.5 µg/m³Agoura, 8 December: 13.7 µg/m³Agoura, 9 December: 20.5 µg/m³Agoura, 10 December: 4.2 µg/m³Agoura, 11 December: 6.2 µg/m³Agoura, 12 December: 7.7 µg/m³Agoura, 13 December: 14.3 µg/m³Agoura, 14 December: 8.5 µg/m³CalexicoCalexico, 28 November: 10.7 µg/m³Calexico, 29 November: 6.1 µg/m³Calexico, 30 November: 10.2 µg/m³Calexico, 1 December: 22.8 µg/m³Calexico, 2 December: 12.6 µg/m³Calexico, 3 December: 15.1 µg/m³Calexico, 4 December: 27.7 µg/m³, 2.2× its usual 12.7Calexico, 5 December: 16.7 µg/m³Calexico, 6 December: no readingCalexico, 7 December: no readingCalexico, 8 December: no readingCalexico, 9 December: no readingCalexico, 10 December: no readingCalexico, 11 December: no readingCalexico, 12 December: no readingCalexico, 13 December: no readingCalexico, 14 December: no readingLake ElsinoreLake Elsinore, 28 November: 2.9 µg/m³Lake Elsinore, 29 November: 1.9 µg/m³Lake Elsinore, 30 November: 4.5 µg/m³Lake Elsinore, 1 December: 4.7 µg/m³Lake Elsinore, 2 December: 11.9 µg/m³Lake Elsinore, 3 December: 15.3 µg/m³Lake Elsinore, 4 December: 26.2 µg/m³, 4.5× its usual 5.8Lake Elsinore, 5 December: 27.3 µg/m³, 4.6× its usual 5.9Lake Elsinore, 6 December: 11.3 µg/m³Lake Elsinore, 7 December: 5.2 µg/m³Lake Elsinore, 8 December: 9.9 µg/m³Lake Elsinore, 9 December: 11.2 µg/m³Lake Elsinore, 10 December: 4.3 µg/m³Lake Elsinore, 11 December: 6.8 µg/m³Lake Elsinore, 12 December: 9.7 µg/m³Lake Elsinore, 13 December: 11.8 µg/m³Lake Elsinore, 14 December: 11.9 µg/m³La Crescenta-Montro…La Crescenta-Montrose, 28 November: 4.1 µg/m³La Crescenta-Montrose, 29 November: 5.1 µg/m³La Crescenta-Montrose, 30 November: 5.5 µg/m³La Crescenta-Montrose, 1 December: 8.2 µg/m³La Crescenta-Montrose, 2 December: 10.5 µg/m³La Crescenta-Montrose, 3 December: 18.6 µg/m³La Crescenta-Montrose, 4 December: 25.0 µg/m³, 4.2× its usual 5.9La Crescenta-Montrose, 5 December: 15.2 µg/m³La Crescenta-Montrose, 6 December: 3.5 µg/m³La Crescenta-Montrose, 7 December: 4.3 µg/m³La Crescenta-Montrose, 8 December: 9.6 µg/m³La Crescenta-Montrose, 9 December: 11.1 µg/m³La Crescenta-Montrose, 10 December: 5.4 µg/m³La Crescenta-Montrose, 11 December: 14.7 µg/m³La Crescenta-Montrose, 12 December: 9.7 µg/m³La Crescenta-Montrose, 13 December: 8.3 µg/m³La Crescenta-Montrose, 14 December: 7.1 µg/m³San DiegoSan Diego, 28 November: 14.4 µg/m³San Diego, 29 November: 6.4 µg/m³San Diego, 30 November: 8.8 µg/m³San Diego, 1 December: 13.2 µg/m³San Diego, 2 December: 9.8 µg/m³San Diego, 3 December: 14.8 µg/m³San Diego, 4 December: 21.3 µg/m³San Diego, 5 December: 29.5 µg/m³, 3.0× its usual 9.8San Diego, 6 December: 37.1 µg/m³, 3.6× its usual 10.3San Diego, 7 December: 9.3 µg/m³San Diego, 8 December: 13.5 µg/m³San Diego, 9 December: 23.0 µg/m³San Diego, 10 December: 7.2 µg/m³San Diego, 11 December: 6.7 µg/m³San Diego, 12 December: 11.0 µg/m³San Diego, 13 December: 11.2 µg/m³San Diego, 14 December: 16.7 µg/m³ComptonCompton, 28 November: 15.0 µg/m³Compton, 29 November: 11.1 µg/m³Compton, 30 November: 11.7 µg/m³Compton, 1 December: 19.1 µg/m³Compton, 2 December: 21.8 µg/m³Compton, 3 December: 19.6 µg/m³Compton, 4 December: 24.0 µg/m³Compton, 5 December: 36.7 µg/m³, 2.2× its usual 16.7Compton, 6 December: 33.1 µg/m³Compton, 7 December: 33.4 µg/m³Compton, 8 December: 28.6 µg/m³Compton, 9 December: 23.5 µg/m³Compton, 10 December: 25.1 µg/m³Compton, 11 December: 12.6 µg/m³Compton, 12 December: 14.3 µg/m³Compton, 13 December: 16.8 µg/m³Compton, 14 December: 19.3 µg/m³Long BeachLong Beach, 28 November: 12.3 µg/m³Long Beach, 29 November: 10.2 µg/m³Long Beach, 30 November: 8.2 µg/m³Long Beach, 1 December: 17.5 µg/m³Long Beach, 2 December: 23.6 µg/m³Long Beach, 3 December: 16.6 µg/m³Long Beach, 4 December: 17.7 µg/m³Long Beach, 5 December: 33.2 µg/m³, 2.6× its usual 12.6Long Beach, 6 December: 25.5 µg/m³, 2.0× its usual 12.5Long Beach, 7 December: 25.4 µg/m³, 2.0× its usual 12.5Long Beach, 8 December: 20.3 µg/m³Long Beach, 9 December: 16.3 µg/m³Long Beach, 10 December: 15.8 µg/m³Long Beach, 11 December: 11.8 µg/m³Long Beach, 12 December: 19.6 µg/m³Long Beach, 13 December: 12.2 µg/m³Long Beach, 14 December: 16.5 µg/m³LomitaLomita, 28 November: 14.4 µg/m³Lomita, 29 November: 6.8 µg/m³Lomita, 30 November: 7.3 µg/m³Lomita, 1 December: 12.7 µg/m³Lomita, 2 December: 15.8 µg/m³Lomita, 3 December: 17.7 µg/m³Lomita, 4 December: 24.3 µg/m³Lomita, 5 December: 28.0 µg/m³, 3.5× its usual 8.1Lomita, 6 December: 28.8 µg/m³, 3.6× its usual 8.1Lomita, 7 December: 9.7 µg/m³Lomita, 8 December: 17.6 µg/m³Lomita, 9 December: 16.4 µg/m³Lomita, 10 December: 8.5 µg/m³Lomita, 11 December: 8.4 µg/m³Lomita, 12 December: 8.5 µg/m³Lomita, 13 December: 11.7 µg/m³Lomita, 14 December: 8.1 µg/m³El CajonEl Cajon, 28 November: 7.3 µg/m³El Cajon, 29 November: 6.5 µg/m³El Cajon, 30 November: 8.1 µg/m³El Cajon, 1 December: 10.6 µg/m³El Cajon, 2 December: 8.9 µg/m³El Cajon, 3 December: 13.9 µg/m³El Cajon, 4 December: 21.0 µg/m³El Cajon, 5 December: 26.2 µg/m³, 2.7× its usual 9.6El Cajon, 6 December: 19.5 µg/m³El Cajon, 7 December: 10.2 µg/m³El Cajon, 8 December: 15.4 µg/m³El Cajon, 9 December: 21.5 µg/m³El Cajon, 10 December: 9.8 µg/m³El Cajon, 11 December: 9.9 µg/m³El Cajon, 12 December: 9.8 µg/m³El Cajon, 13 December: 9.2 µg/m³El Cajon, 14 December: 14.2 µg/m³OceansideOceanside, 28 November: 17.2 µg/m³Oceanside, 29 November: 7.6 µg/m³Oceanside, 30 November: 6.1 µg/m³Oceanside, 1 December: 6.3 µg/m³Oceanside, 2 December: 9.3 µg/m³Oceanside, 3 December: 11.5 µg/m³Oceanside, 4 December: 12.8 µg/m³Oceanside, 5 December: 25.3 µg/m³, 3.2× its usual 7.9Oceanside, 6 December: 25.9 µg/m³, 3.2× its usual 8.0Oceanside, 7 December: 13.7 µg/m³Oceanside, 8 December: 11.5 µg/m³Oceanside, 9 December: 15.3 µg/m³Oceanside, 10 December: 4.7 µg/m³Oceanside, 11 December: 7.9 µg/m³Oceanside, 12 December: 7.8 µg/m³Oceanside, 13 December: 10.8 µg/m³Oceanside, 14 December: 11.6 µg/m³Imperial BeachImperial Beach, 28 November: 15.0 µg/m³Imperial Beach, 29 November: 8.4 µg/m³Imperial Beach, 30 November: 12.1 µg/m³Imperial Beach, 1 December: 32.9 µg/m³Imperial Beach, 2 December: 29.1 µg/m³Imperial Beach, 3 December: 25.3 µg/m³Imperial Beach, 4 December: 23.6 µg/m³Imperial Beach, 5 December: 29.8 µg/m³Imperial Beach, 6 December: 45.4 µg/m³, 2.5× its usual 18.5Imperial Beach, 7 December: 39.3 µg/m³, 2.1× its usual 18.5Imperial Beach, 8 December: 32.9 µg/m³Imperial Beach, 9 December: 30.4 µg/m³Imperial Beach, 10 December: 13.2 µg/m³Imperial Beach, 11 December: 9.4 µg/m³Imperial Beach, 12 December: 20.0 µg/m³Imperial Beach, 13 December: 14.3 µg/m³Imperial Beach, 14 December: 27.8 µg/m³Chula VistaChula Vista, 28 November: 10.2 µg/m³Chula Vista, 29 November: 6.0 µg/m³Chula Vista, 30 November: 6.7 µg/m³Chula Vista, 1 December: 14.8 µg/m³Chula Vista, 2 December: 10.4 µg/m³Chula Vista, 3 December: 16.1 µg/m³Chula Vista, 4 December: 18.5 µg/m³Chula Vista, 5 December: 24.5 µg/m³Chula Vista, 6 December: 28.8 µg/m³, 3.2× its usual 9.1Chula Vista, 7 December: 8.1 µg/m³Chula Vista, 8 December: 11.5 µg/m³Chula Vista, 9 December: 23.9 µg/m³Chula Vista, 10 December: 7.1 µg/m³Chula Vista, 11 December: 6.4 µg/m³Chula Vista, 12 December: 10.4 µg/m³Chula Vista, 13 December: 9.8 µg/m³Chula Vista, 14 December: 15.3 µg/m³VallejoVallejo, 28 November: 8.3 µg/m³Vallejo, 29 November: 7.2 µg/m³Vallejo, 30 November: 15.0 µg/m³Vallejo, 1 December: 13.0 µg/m³Vallejo, 2 December: 11.2 µg/m³Vallejo, 3 December: 19.9 µg/m³Vallejo, 4 December: 22.5 µg/m³Vallejo, 5 December: 19.3 µg/m³Vallejo, 6 December: 18.2 µg/m³Vallejo, 7 December: 37.6 µg/m³, 4.7× its usual 8.0Vallejo, 8 December: 28.0 µg/m³, 3.5× its usual 8.1Vallejo, 9 December: no readingVallejo, 10 December: no readingVallejo, 11 December: 26.3 µg/m³, 3.3× its usual 8.0Vallejo, 12 December: 7.5 µg/m³Vallejo, 13 December: 4.1 µg/m³Vallejo, 14 December: 4.2 µg/m³MartinezMartinez, 28 November: 6.7 µg/m³Martinez, 29 November: 9.0 µg/m³Martinez, 30 November: 21.3 µg/m³Martinez, 1 December: 16.1 µg/m³Martinez, 2 December: 9.5 µg/m³Martinez, 3 December: no readingMartinez, 4 December: no readingMartinez, 5 December: no readingMartinez, 6 December: 16.0 µg/m³Martinez, 7 December: 37.1 µg/m³, 4.9× its usual 7.5Martinez, 8 December: 23.0 µg/m³Martinez, 9 December: 8.0 µg/m³Martinez, 10 December: 24.7 µg/m³Martinez, 11 December: 31.0 µg/m³, 4.2× its usual 7.4Martinez, 12 December: 11.3 µg/m³Martinez, 13 December: 5.7 µg/m³Martinez, 14 December: 6.1 µg/m³OaklandOakland, 28 November: 5.2 µg/m³Oakland, 29 November: 7.4 µg/m³Oakland, 30 November: 9.5 µg/m³Oakland, 1 December: 11.8 µg/m³Oakland, 2 December: 11.0 µg/m³Oakland, 3 December: 16.0 µg/m³Oakland, 4 December: 20.2 µg/m³Oakland, 5 December: 18.8 µg/m³Oakland, 6 December: 17.6 µg/m³Oakland, 7 December: 35.5 µg/m³, 3.7× its usual 9.6Oakland, 8 December: 29.7 µg/m³, 3.1× its usual 9.5Oakland, 9 December: 6.7 µg/m³Oakland, 10 December: 18.3 µg/m³Oakland, 11 December: 26.3 µg/m³, 2.7× its usual 9.6Oakland, 12 December: 8.1 µg/m³Oakland, 13 December: 3.8 µg/m³Oakland, 14 December: 5.8 µg/m³BerkeleyBerkeley, 28 November: 8.4 µg/m³Berkeley, 29 November: 8.4 µg/m³Berkeley, 30 November: 11.8 µg/m³Berkeley, 1 December: 11.7 µg/m³Berkeley, 2 December: 13.2 µg/m³Berkeley, 3 December: 19.5 µg/m³Berkeley, 4 December: 21.4 µg/m³Berkeley, 5 December: 19.2 µg/m³Berkeley, 6 December: 18.0 µg/m³Berkeley, 7 December: 35.1 µg/m³, 3.2× its usual 11.0Berkeley, 8 December: 30.0 µg/m³, 2.7× its usual 11.0Berkeley, 9 December: 9.2 µg/m³Berkeley, 10 December: 20.0 µg/m³Berkeley, 11 December: 26.5 µg/m³, 2.4× its usual 11.0Berkeley, 12 December: 11.2 µg/m³Berkeley, 13 December: 6.9 µg/m³Berkeley, 14 December: 9.3 µg/m³RichmondRichmond, 28 November: 8.8 µg/m³Richmond, 29 November: 6.8 µg/m³Richmond, 30 November: 13.8 µg/m³Richmond, 1 December: 8.9 µg/m³Richmond, 2 December: 8.7 µg/m³Richmond, 3 December: 13.3 µg/m³Richmond, 4 December: 17.1 µg/m³Richmond, 5 December: 13.8 µg/m³Richmond, 6 December: 13.0 µg/m³Richmond, 7 December: 32.3 µg/m³, 3.2× its usual 10.0Richmond, 8 December: 25.1 µg/m³, 2.5× its usual 10.0Richmond, 9 December: 6.5 µg/m³Richmond, 10 December: 20.9 µg/m³Richmond, 11 December: 23.1 µg/m³Richmond, 12 December: 7.5 µg/m³Richmond, 13 December: 10.0 µg/m³Richmond, 14 December: 8.2 µg/m³San FranciscoSan Francisco, 28 November: no readingSan Francisco, 29 November: no readingSan Francisco, 30 November: no readingSan Francisco, 1 December: no readingSan Francisco, 2 December: no readingSan Francisco, 3 December: 10.8 µg/m³San Francisco, 4 December: 15.3 µg/m³San Francisco, 5 December: 11.9 µg/m³San Francisco, 6 December: 13.8 µg/m³San Francisco, 7 December: 32.2 µg/m³, 3.8× its usual 8.4San Francisco, 8 December: 23.5 µg/m³San Francisco, 9 December: 6.9 µg/m³San Francisco, 10 December: 16.5 µg/m³San Francisco, 11 December: 20.9 µg/m³San Francisco, 12 December: 7.5 µg/m³San Francisco, 13 December: 3.8 µg/m³San Francisco, 14 December: 6.0 µg/m³South San FranciscoSouth San Francisco, 28 November: 6.7 µg/m³South San Francisco, 29 November: 8.5 µg/m³South San Francisco, 30 November: 12.0 µg/m³South San Francisco, 1 December: 12.7 µg/m³South San Francisco, 2 December: 9.4 µg/m³South San Francisco, 3 December: 11.1 µg/m³South San Francisco, 4 December: 21.5 µg/m³South San Francisco, 5 December: 13.8 µg/m³South San Francisco, 6 December: 12.4 µg/m³South San Francisco, 7 December: 28.5 µg/m³, 3.7× its usual 7.7South San Francisco, 8 December: 30.0 µg/m³, 3.8× its usual 7.9South San Francisco, 9 December: 7.0 µg/m³South San Francisco, 10 December: 19.6 µg/m³South San Francisco, 11 December: 24.8 µg/m³South San Francisco, 12 December: 5.7 µg/m³South San Francisco, 13 December: 4.0 µg/m³South San Francisco, 14 December: 4.6 µg/m³San RafaelSan Rafael, 28 November: 4.8 µg/m³San Rafael, 29 November: 5.7 µg/m³San Rafael, 30 November: 12.7 µg/m³San Rafael, 1 December: 11.0 µg/m³San Rafael, 2 December: 6.4 µg/m³San Rafael, 3 December: 10.3 µg/m³San Rafael, 4 December: 13.0 µg/m³San Rafael, 5 December: 9.1 µg/m³San Rafael, 6 December: 10.3 µg/m³San Rafael, 7 December: 27.9 µg/m³, 4.2× its usual 6.6San Rafael, 8 December: 18.4 µg/m³San Rafael, 9 December: 5.6 µg/m³San Rafael, 10 December: 20.8 µg/m³San Rafael, 11 December: 22.0 µg/m³San Rafael, 12 December: 6.7 µg/m³San Rafael, 13 December: 5.5 µg/m³San Rafael, 14 December: no readingSan LeandroSan Leandro, 28 November: 2.9 µg/m³San Leandro, 29 November: 4.6 µg/m³San Leandro, 30 November: 8.8 µg/m³San Leandro, 1 December: 7.7 µg/m³San Leandro, 2 December: 7.5 µg/m³San Leandro, 3 December: 9.2 µg/m³San Leandro, 4 December: 15.0 µg/m³San Leandro, 5 December: 16.5 µg/m³San Leandro, 6 December: 11.6 µg/m³San Leandro, 7 December: 27.7 µg/m³, 4.3× its usual 6.5San Leandro, 8 December: 20.3 µg/m³San Leandro, 9 December: 3.6 µg/m³San Leandro, 10 December: 14.5 µg/m³San Leandro, 11 December: 24.5 µg/m³San Leandro, 12 December: 6.7 µg/m³San Leandro, 13 December: 3.0 µg/m³San Leandro, 14 December: 5.1 µg/m³ConcordConcord, 28 November: 4.8 µg/m³Concord, 29 November: no readingConcord, 30 November: no readingConcord, 1 December: no readingConcord, 2 December: no readingConcord, 3 December: 10.2 µg/m³Concord, 4 December: 13.1 µg/m³Concord, 5 December: 10.3 µg/m³Concord, 6 December: 9.7 µg/m³Concord, 7 December: 26.5 µg/m³, 4.3× its usual 6.1Concord, 8 December: 14.6 µg/m³Concord, 9 December: 2.8 µg/m³Concord, 10 December: 18.8 µg/m³Concord, 11 December: 25.4 µg/m³, 4.3× its usual 5.9Concord, 12 December: 5.8 µg/m³Concord, 13 December: 1.8 µg/m³Concord, 14 December: 3.3 µg/m³GaltGalt, 28 November: 6.7 µg/m³Galt, 29 November: 12.1 µg/m³Galt, 30 November: 18.3 µg/m³Galt, 1 December: 15.3 µg/m³Galt, 2 December: no readingGalt, 3 December: 17.8 µg/m³Galt, 4 December: 16.6 µg/m³Galt, 5 December: 15.8 µg/m³Galt, 6 December: 21.5 µg/m³Galt, 7 December: 26.5 µg/m³, 3.2× its usual 8.3Galt, 8 December: 12.3 µg/m³Galt, 9 December: 10.3 µg/m³Galt, 10 December: 17.0 µg/m³Galt, 11 December: 19.7 µg/m³Galt, 12 December: 17.2 µg/m³Galt, 13 December: 7.6 µg/m³Galt, 14 December: 3.8 µg/m³Yuba CityYuba City, 28 November: 12.7 µg/m³Yuba City, 29 November: 14.2 µg/m³Yuba City, 30 November: 20.9 µg/m³Yuba City, 1 December: 22.1 µg/m³Yuba City, 2 December: 23.3 µg/m³Yuba City, 3 December: 21.6 µg/m³Yuba City, 4 December: 23.5 µg/m³Yuba City, 5 December: 22.0 µg/m³Yuba City, 6 December: 22.5 µg/m³Yuba City, 7 December: 26.3 µg/m³, 3.1× its usual 8.6Yuba City, 8 December: 8.8 µg/m³Yuba City, 9 December: no readingYuba City, 10 December: no readingYuba City, 11 December: no readingYuba City, 12 December: no readingYuba City, 13 December: no readingYuba City, 14 December: no readingPleasantonPleasanton, 28 November: 4.2 µg/m³Pleasanton, 29 November: 6.7 µg/m³Pleasanton, 30 November: 9.1 µg/m³Pleasanton, 1 December: 11.4 µg/m³Pleasanton, 2 December: 7.5 µg/m³Pleasanton, 3 December: 9.0 µg/m³Pleasanton, 4 December: 13.6 µg/m³Pleasanton, 5 December: 12.7 µg/m³Pleasanton, 6 December: 9.6 µg/m³Pleasanton, 7 December: 22.0 µg/m³Pleasanton, 8 December: 21.9 µg/m³Pleasanton, 9 December: 4.0 µg/m³Pleasanton, 10 December: 16.1 µg/m³Pleasanton, 11 December: 27.1 µg/m³, 4.0× its usual 6.8Pleasanton, 12 December: 7.0 µg/m³Pleasanton, 13 December: 1.8 µg/m³Pleasanton, 14 December: 3.5 µg/m³VacavilleVacaville, 28 November: 8.4 µg/m³Vacaville, 29 November: 9.4 µg/m³Vacaville, 30 November: 17.0 µg/m³Vacaville, 1 December: 14.4 µg/m³Vacaville, 2 December: 8.1 µg/m³Vacaville, 3 December: 12.4 µg/m³Vacaville, 4 December: 15.4 µg/m³Vacaville, 5 December: 13.4 µg/m³Vacaville, 6 December: 14.3 µg/m³Vacaville, 7 December: 24.8 µg/m³Vacaville, 8 December: 9.6 µg/m³Vacaville, 9 December: 6.7 µg/m³Vacaville, 10 December: 18.8 µg/m³Vacaville, 11 December: 26.8 µg/m³, 3.7× its usual 7.3Vacaville, 12 December: 11.7 µg/m³Vacaville, 13 December: 3.8 µg/m³Vacaville, 14 December: 4.1 µg/m³LivermoreLivermore, 28 November: 10.4 µg/m³Livermore, 29 November: 13.9 µg/m³Livermore, 30 November: 13.0 µg/m³Livermore, 1 December: 13.0 µg/m³Livermore, 2 December: 7.1 µg/m³Livermore, 3 December: 12.3 µg/m³Livermore, 4 December: 15.8 µg/m³Livermore, 5 December: 13.7 µg/m³Livermore, 6 December: no readingLivermore, 7 December: 22.2 µg/m³Livermore, 8 December: 13.7 µg/m³Livermore, 9 December: 4.3 µg/m³Livermore, 10 December: 19.2 µg/m³Livermore, 11 December: 25.6 µg/m³, 3.7× its usual 7.0Livermore, 12 December: 10.3 µg/m³Livermore, 13 December: 4.2 µg/m³Livermore, 14 December: 6.1 µg/m³28 Nov301 Dec2468101214
The 60 cities with the highest readings of 61, 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
FontanaCalifornia, United States3 51.75 December10.05.2×
PortervilleCalifornia, United States9 54.86 December11.24.9×
MartinezCalifornia, United States2 37.17 December7.54.9×
AgouraCalifornia, United States2 29.64 December6.14.9×
VallejoCalifornia, United States3 37.67 December8.04.7×
Lake ElsinoreCalifornia, United States2 27.35 December5.94.6×
Palo AltoCalifornia, United States5 41.611 December9.24.5×
RiversideCalifornia, United States3 53.55 December12.24.4×
San LeandroCalifornia, United States1 27.77 December6.54.3×
ConcordCalifornia, United States2 26.57 December6.14.3×
ClovisCalifornia, United States10 51.36 December12.14.2×
BurbankCalifornia, United States3 44.25 December10.54.2×
San RafaelCalifornia, United States1 27.97 December6.64.2×
La Crescenta-MontroseCalifornia, United States1 25.04 December5.94.2×
Jurupa ValleyCalifornia, United States4 58.05 December14.64.0×
Los AngelesCalifornia, United States4 45.25 December11.34.0×
Santa MonicaCalifornia, United States3 32.05 December8.04.0×
PleasantonCalifornia, United States1 27.111 December6.84.0×
MercedCalifornia, United States6 51.57 December13.23.9×
VisaliaCalifornia, United States5 64.84 December17.03.8×
WoodlandCalifornia, United States6 42.57 December11.33.8×
San FranciscoCalifornia, United States1 32.27 December8.43.8×
South San FranciscoCalifornia, United States2 30.08 December7.93.8×
OaklandCalifornia, United States3 35.57 December9.63.7×
SacramentoCalifornia, United States5 35.37 December9.63.7×
VacavilleCalifornia, United States1 26.811 December7.33.7×
LivermoreCalifornia, United States1 25.611 December7.03.7×
CorcoranCalifornia, United States7 48.15 December13.23.6×
MantecaCalifornia, United States9 44.07 December12.33.6×
San DiegoCalifornia, United States2 37.16 December10.33.6×
LomitaCalifornia, United States2 28.86 December8.13.6×
TurlockCalifornia, United States9 46.57 December13.43.5×
MaderaCalifornia, United States8 46.47 December13.13.5×
HanfordCalifornia, United States9 53.85 December16.03.4×
BakersfieldCalifornia, United States9 61.07 December18.43.3×
FresnoCalifornia, United States8 57.16 December18.03.2×
BerkeleyCalifornia, United States3 35.17 December11.03.2×
RichmondCalifornia, United States2 32.37 December10.03.2×
Chula VistaCalifornia, United States1 28.86 December9.13.2×
GaltCalifornia, United States1 26.57 December8.33.2×
OceansideCalifornia, United States2 25.96 December8.03.2×
San JoseCalifornia, United States4 32.38 December10.33.1×
InglewoodCalifornia, United States4 32.05 December10.43.1×
ChicoCalifornia, United States5 28.37 December9.03.1×
Yuba CityCalifornia, United States1 26.37 December8.63.1×
FlorinCalifornia, United States9 44.17 December14.53.0×
AnaheimCalifornia, United States4 40.25 December13.23.0×
Arden-ArcadeCalifornia, United States4 31.47 December11.02.9×
TorranceCalifornia, United States3 31.35 December10.82.9×
CarsonCalifornia, United States3 34.35 December12.42.8×
StocktonCalifornia, United States3 39.04 December14.22.7×
MedfordOregon, United States2 30.84 December11.62.7×
RosevilleCalifornia, United States1 26.31 December9.72.7×
El CajonCalifornia, United States1 26.25 December9.62.7×
ModestoCalifornia, United States4 38.84 December14.72.6×
Long BeachCalifornia, United States3 33.25 December12.62.6×
AltamontOregon, United States1 25.07 December9.52.6×
Imperial BeachCalifornia, United States2 45.46 December18.52.5×
HawthorneCalifornia, United States3 32.56 December14.12.3×
ComptonCalifornia, United States1 36.75 December16.72.2×
CalexicoCalifornia, United States1 27.74 December12.72.2×

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 16 of 130 episodes in the United States since our records began, by cities reached.

Bars: cities reached; colour: the level of the episode's highest daily reading. All 130.

Use this page

SmogRank, California and Oregon, United States, December 2024: 61 cities with PM2.5 at twice their usual or more, 1 to 11 December 2024, smogrank.com/episodes/2024-12-california-and-oregon-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.