SmogRank / Episodes / United States

Oregon and California, United States, August 2024

For 2 days, from 1 to 2 August 2024, 8 cities in the United States had PM2.5 at least twice their usual for the time of year. The worst reading was Chico, California, United States: 81.2 µg/m³ on 2 August, about 11× its usual 7.1.

No cause namedWe have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached8in 1 country
Days21 to 2 August 2024
Worst day1 August5 cities counted
Furthest above usual11×Paradise

Day by day

1 August 5 cities at twice their usual or more
RedmondEugeneRoseburgGrants PassAlbanyCorvallisSalemWoodburnCanbyThe DallesGreshamDallasMilwaukieTigardPortlandBeavertonMcMinnvilleReddingVancouverCoos BaySalmon CreekHillsboroForest GroveLongviewHermistonPendletonTri-CitiesCentraliaSpanish SpringsEllensburgRenoLaceyParklandWalla WallaCarson CityAberdeenMoses LakeNampaMeridianBoiseLewistonPullmanMoscowBendSunnysideParadiseAshlandMedfordYakimaAltamontChico
29 Jul30311 Aug2345
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

BendBend, 29 July: 68.9 µg/m³, 8.5× usualBend, 30 July: 19.2 µg/m³, 2.4× usualBend, 31 July: 26.9 µg/m³, 3.3× usualBend, 1 August: 13.7 µg/m³, 1.7× usualBend, 2 August: 27.4 µg/m³, 3.4× usualBend, 3 August: 16.5 µg/m³, 2.0× usualBend, 4 August: 10.0 µg/m³, 1.2× usualBend, 5 August: 27.2 µg/m³, 3.4× usualYakimaYakima, 29 July: 40.1 µg/m³, 7.7× usualYakima, 30 July: 5.4 µg/m³, 1.0× usualYakima, 31 July: 8.6 µg/m³, 1.7× usualYakima, 1 August: 13.2 µg/m³, 2.5× usualYakima, 2 August: 38.0 µg/m³, 7.3× usualYakima, 3 August: 19.9 µg/m³, 3.8× usualYakima, 4 August: 11.9 µg/m³, 2.3× usualYakima, 5 August: 14.2 µg/m³, 2.7× usualParadiseParadise, 29 July: 14.6 µg/m³, 2.4× usualParadise, 30 July: 9.5 µg/m³, 1.5× usualParadise, 31 July: 132.0 µg/m³, 21× usualParadise, 1 August: 25.0 µg/m³, 4.0× usualParadise, 2 August: 14.7 µg/m³, 2.4× usualParadise, 3 August: 12.7 µg/m³, 2.0× usualParadise, 4 August: 8.5 µg/m³, 1.4× usualParadise, 5 August: 6.9 µg/m³, 1.1× usualAltamontAltamont, 29 July: 11.1 µg/m³, 1.6× usualAltamont, 30 July: 2.5 µg/m³, 0.4× usualAltamont, 31 July: 17.8 µg/m³, 2.5× usualAltamont, 1 August: 58.8 µg/m³, 8.3× usualAltamont, 2 August: 28.2 µg/m³, 4.0× usualAltamont, 3 August: 20.6 µg/m³, 2.9× usualAltamont, 4 August: 10.9 µg/m³, 1.5× usualAltamont, 5 August: 13.4 µg/m³, 1.9× usualMedfordMedford, 29 July: 8.3 µg/m³, 1.4× usualMedford, 30 July: 2.3 µg/m³, 0.4× usualMedford, 31 July: 12.9 µg/m³, 2.2× usualMedford, 1 August: 32.7 µg/m³, 5.5× usualMedford, 2 August: 15.1 µg/m³, 2.5× usualMedford, 3 August: 21.5 µg/m³, 3.6× usualMedford, 4 August: 19.8 µg/m³, 3.3× usualMedford, 5 August: 17.0 µg/m³, 2.8× usualChicoChico, 29 July: 11.9 µg/m³, 1.7× usualChico, 30 July: 17.5 µg/m³, 2.5× usualChico, 31 July: 16.1 µg/m³, 2.3× usualChico, 1 August: 31.8 µg/m³, 4.5× usualChico, 2 August: 81.2 µg/m³, 11× usualChico, 3 August: 22.8 µg/m³, 3.2× usualChico, 4 August: 16.2 µg/m³, 2.3× usualChico, 5 August: 11.2 µg/m³, 1.6× usualAshlandAshland, 29 July: 7.9 µg/m³, 1.3× usualAshland, 30 July: 2.3 µg/m³, 0.4× usualAshland, 31 July: 8.1 µg/m³, 1.4× usualAshland, 1 August: 30.1 µg/m³, 5.1× usualAshland, 2 August: 13.8 µg/m³, 2.3× usualAshland, 3 August: 19.8 µg/m³, 3.4× usualAshland, 4 August: 16.5 µg/m³, 2.8× usualAshland, 5 August: 17.4 µg/m³, 2.9× usualSunnysideSunnyside, 29 July: 22.2 µg/m³, 3.2× usualSunnyside, 30 July: 7.5 µg/m³, 1.1× usualSunnyside, 31 July: 6.7 µg/m³, 1.0× usualSunnyside, 1 August: 12.6 µg/m³, 1.8× usualSunnyside, 2 August: 25.9 µg/m³, 3.7× usualSunnyside, 3 August: 27.1 µg/m³, 3.9× usualSunnyside, 4 August: 18.5 µg/m³, 2.6× usualSunnyside, 5 August: 14.7 µg/m³, 2.1× usual29 Jul30311 Aug2345
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
ParadiseCalifornia, United States1 132.031 July6.221×
ChicoCalifornia, United States2 81.22 August7.111×
BendOregon, United States1 68.929 July8.18.5×
AltamontOregon, United States2 58.81 August7.18.3×
YakimaWashington, United States1 40.129 July5.27.7×
MedfordOregon, United States1 32.71 August6.05.5×
AshlandOregon, United States1 30.11 August5.95.1×
SunnysideWashington, United States1 27.13 August7.03.9×

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

Number 125 of 131 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 131.

Use this page

SmogRank, Oregon and California, United States, August 2024: 8 cities with PM2.5 at twice their usual or more, 1 to 2 August 2024, smogrank.com/episodes/2024-08-oregon-and-california-united-states (accessed 3 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.