SmogRank / Episodes / United States
Oregon, Idaho and Utah, United States, August 2024
For 3 days, from 7 to 9 August 2024, 25 cities in the United States had PM2.5 at least twice their usual for the time of year. The worst reading was Garden City, Idaho, United States: 99.9 µg/m³ on 8 August, about 15× its usual 6.8. Ended 9 August.
No cause named We have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached 25 in 1 country
Days 3 7 to 9 August 2024
Worst day 8 August 22 cities counted
Furthest above usual 15× Garden City
Day by day
Play 8 August 22 cities at twice their usual or more
Ontario Yreka Redding Red Bluff Sweet Home Cottage Grove Idaho Falls Stayton Eugene Silverton Roseburg Green Magna Albany Rexburg Salem Herriman Bountiful Corvallis West Jordan Conda Dallas Highland Cedar Hills Orem Coos Bay Weiser Baker City Redmond Prineville Madras Millcreek Burley Salt Lake City West Valley City Smithfield Bend Tooele Stansbury park North Ogden Twin Falls Pocatello Preston Nampa Grants Pass Altamont Meridian Ashland Medford Talent Garden City 4 Aug 5 6 7 8 9 10 11 12 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
Altamont Altamont, 4 August: 10.9 µg/m³ Altamont, 5 August: 13.4 µg/m³ Altamont, 6 August: 22.9 µg/m³ Altamont, 7 August: 45.7 µg/m³, 7.3× its usual 6.3 Altamont, 8 August: 35.3 µg/m³, 5.6× its usual 6.3 Altamont, 9 August: 82.4 µg/m³ Altamont, 10 August: 38.8 µg/m³ Altamont, 11 August: 61.2 µg/m³ Altamont, 12 August: 26.3 µg/m³ Medford Medford, 4 August: 19.8 µg/m³ Medford, 5 August: 17.0 µg/m³ Medford, 6 August: 13.6 µg/m³ Medford, 7 August: 36.8 µg/m³, 5.8× its usual 6.3 Medford, 8 August: 65.7 µg/m³, 10× its usual 6.3 Medford, 9 August: 26.6 µg/m³ Medford, 10 August: 24.1 µg/m³ Medford, 11 August: 36.9 µg/m³ Medford, 12 August: 4.9 µg/m³ Garden City Garden City, 4 August: 24.5 µg/m³ Garden City, 5 August: 14.5 µg/m³ Garden City, 6 August: 23.0 µg/m³ Garden City, 7 August: 34.5 µg/m³, 5.1× its usual 6.7 Garden City, 8 August: 99.9 µg/m³, 15× its usual 6.8 Garden City, 9 August: 57.3 µg/m³, 8.6× its usual 6.7 Garden City, 10 August: 23.5 µg/m³ Garden City, 11 August: 19.7 µg/m³ Garden City, 12 August: 19.5 µg/m³ Bend Bend, 4 August: 10.0 µg/m³ Bend, 5 August: 27.2 µg/m³ Bend, 6 August: 31.3 µg/m³ Bend, 7 August: 33.6 µg/m³, 3.9× its usual 8.6 Bend, 8 August: 28.5 µg/m³, 3.2× its usual 8.9 Bend, 9 August: 23.8 µg/m³ Bend, 10 August: 21.1 µg/m³ Bend, 11 August: 18.8 µg/m³ Bend, 12 August: 40.5 µg/m³ Grants Pass Grants Pass, 4 August: 38.4 µg/m³ Grants Pass, 5 August: 12.7 µg/m³ Grants Pass, 6 August: 6.2 µg/m³ Grants Pass, 7 August: 32.5 µg/m³, 6.5× its usual 4.5 Grants Pass, 8 August: 34.3 µg/m³, 6.9× its usual 4.4 Grants Pass, 9 August: 24.3 µg/m³ Grants Pass, 10 August: 17.0 µg/m³ Grants Pass, 11 August: 23.3 µg/m³ Grants Pass, 12 August: 2.0 µg/m³ Twin Falls Twin Falls, 4 August: 18.0 µg/m³ Twin Falls, 5 August: 13.3 µg/m³ Twin Falls, 6 August: 14.0 µg/m³ Twin Falls, 7 August: 31.4 µg/m³, 4.8× its usual 6.6 Twin Falls, 8 August: 30.3 µg/m³, 4.6× its usual 6.6 Twin Falls, 9 August: 21.5 µg/m³ Twin Falls, 10 August: 20.3 µg/m³ Twin Falls, 11 August: 14.0 µg/m³ Twin Falls, 12 August: 7.8 µg/m³ Pocatello Pocatello, 4 August: 12.8 µg/m³ Pocatello, 5 August: 15.4 µg/m³ Pocatello, 6 August: 7.3 µg/m³ Pocatello, 7 August: 29.5 µg/m³, 5.0× its usual 5.9 Pocatello, 8 August: 23.9 µg/m³ Pocatello, 9 August: 26.8 µg/m³, 4.6× its usual 5.8 Pocatello, 10 August: 17.4 µg/m³ Pocatello, 11 August: 13.9 µg/m³ Pocatello, 12 August: 9.1 µg/m³ Burley Burley, 4 August: 15.1 µg/m³ Burley, 5 August: 13.7 µg/m³ Burley, 6 August: 9.7 µg/m³ Burley, 7 August: 29.1 µg/m³, 3.5× its usual 8.4 Burley, 8 August: 18.2 µg/m³ Burley, 9 August: 15.2 µg/m³ Burley, 10 August: 15.7 µg/m³ Burley, 11 August: 13.2 µg/m³ Burley, 12 August: 10.8 µg/m³ Redmond Redmond, 4 August: 11.4 µg/m³ Redmond, 5 August: 30.3 µg/m³ Redmond, 6 August: 21.7 µg/m³ Redmond, 7 August: 29.0 µg/m³, 2.5× its usual 11.6 Redmond, 8 August: 32.7 µg/m³, 2.7× its usual 12.1 Redmond, 9 August: 20.9 µg/m³ Redmond, 10 August: 19.1 µg/m³ Redmond, 11 August: 16.5 µg/m³ Redmond, 12 August: 27.1 µg/m³ Madras Madras, 4 August: 15.3 µg/m³ Madras, 5 August: 23.1 µg/m³ Madras, 6 August: 16.6 µg/m³ Madras, 7 August: 25.1 µg/m³, 2.4× its usual 10.6 Madras, 8 August: 30.7 µg/m³, 2.9× its usual 10.6 Madras, 9 August: 18.9 µg/m³ Madras, 10 August: 17.4 µg/m³ Madras, 11 August: 11.4 µg/m³ Madras, 12 August: 17.0 µg/m³ Meridian Meridian, 4 August: 27.7 µg/m³ Meridian, 5 August: 16.5 µg/m³ Meridian, 6 August: 19.0 µg/m³ Meridian, 7 August: 24.2 µg/m³ Meridian, 8 August: 74.4 µg/m³, 9.0× its usual 8.3 Meridian, 9 August: 51.9 µg/m³, 6.3× its usual 8.3 Meridian, 10 August: 24.0 µg/m³ Meridian, 11 August: 18.4 µg/m³ Meridian, 12 August: 22.4 µg/m³ Nampa Nampa, 4 August: 21.6 µg/m³ Nampa, 5 August: 15.3 µg/m³ Nampa, 6 August: 17.3 µg/m³ Nampa, 7 August: 17.7 µg/m³ Nampa, 8 August: 63.5 µg/m³, 6.5× its usual 9.7 Nampa, 9 August: 55.0 µg/m³, 5.7× its usual 9.6 Nampa, 10 August: 22.0 µg/m³ Nampa, 11 August: 16.5 µg/m³ Nampa, 12 August: 21.0 µg/m³ Talent Talent, 4 August: 16.6 µg/m³ Talent, 5 August: 16.3 µg/m³ Talent, 6 August: 10.5 µg/m³ Talent, 7 August: 22.5 µg/m³ Talent, 8 August: 63.4 µg/m³, 11× its usual 6.0 Talent, 9 August: 24.2 µg/m³ Talent, 10 August: 19.3 µg/m³ Talent, 11 August: 32.2 µg/m³ Talent, 12 August: 4.2 µg/m³ Ashland Ashland, 4 August: 16.4 µg/m³ Ashland, 5 August: 18.5 µg/m³ Ashland, 6 August: 11.8 µg/m³ Ashland, 7 August: 22.2 µg/m³ Ashland, 8 August: 56.3 µg/m³, 9.2× its usual 6.1 Ashland, 9 August: 24.5 µg/m³ Ashland, 10 August: 20.0 µg/m³ Ashland, 11 August: 35.9 µg/m³ Ashland, 12 August: 5.3 µg/m³ Smithfield Smithfield, 4 August: 5.2 µg/m³ Smithfield, 5 August: 13.1 µg/m³ Smithfield, 6 August: 6.1 µg/m³ Smithfield, 7 August: 18.6 µg/m³ Smithfield, 8 August: 31.3 µg/m³, 3.8× its usual 8.3 Smithfield, 9 August: 27.3 µg/m³, 3.3× its usual 8.3 Smithfield, 10 August: 9.7 µg/m³ Smithfield, 11 August: 15.9 µg/m³ Smithfield, 12 August: 6.2 µg/m³ North Ogden North Ogden, 4 August: 6.2 µg/m³ North Ogden, 5 August: 11.0 µg/m³ North Ogden, 6 August: 5.2 µg/m³ North Ogden, 7 August: 17.4 µg/m³ North Ogden, 8 August: 30.7 µg/m³, 4.7× its usual 6.6 North Ogden, 9 August: 16.8 µg/m³ North Ogden, 10 August: 6.9 µg/m³ North Ogden, 11 August: 14.0 µg/m³ North Ogden, 12 August: 4.1 µg/m³ Prineville Prineville, 4 August: 11.3 µg/m³ Prineville, 5 August: 18.6 µg/m³ Prineville, 6 August: 13.1 µg/m³ Prineville, 7 August: 13.9 µg/m³ Prineville, 8 August: 29.5 µg/m³, 2.9× its usual 10.1 Prineville, 9 August: 18.8 µg/m³ Prineville, 10 August: 16.0 µg/m³ Prineville, 11 August: 11.8 µg/m³ Prineville, 12 August: 22.6 µg/m³ Millcreek Millcreek, 4 August: 7.6 µg/m³ Millcreek, 5 August: 13.1 µg/m³ Millcreek, 6 August: 10.2 µg/m³ Millcreek, 7 August: 19.2 µg/m³ Millcreek, 8 August: 29.0 µg/m³, 3.2× its usual 9.1 Millcreek, 9 August: 11.3 µg/m³ Millcreek, 10 August: 8.9 µg/m³ Millcreek, 11 August: 7.7 µg/m³ Millcreek, 12 August: 9.5 µg/m³ Preston Preston, 4 August: 4.6 µg/m³ Preston, 5 August: 8.8 µg/m³ Preston, 6 August: 3.4 µg/m³ Preston, 7 August: 14.4 µg/m³ Preston, 8 August: 28.5 µg/m³, 5.7× its usual 4.3 Preston, 9 August: 19.0 µg/m³ Preston, 10 August: 6.1 µg/m³ Preston, 11 August: 11.3 µg/m³ Preston, 12 August: 5.0 µg/m³ Stansbury park Stansbury park, 4 August: 7.1 µg/m³ Stansbury park, 5 August: 16.8 µg/m³ Stansbury park, 6 August: 11.0 µg/m³ Stansbury park, 7 August: 17.5 µg/m³ Stansbury park, 8 August: 28.3 µg/m³, 4.0× its usual 7.1 Stansbury park, 9 August: 10.2 µg/m³ Stansbury park, 10 August: 7.5 µg/m³ Stansbury park, 11 August: 17.0 µg/m³ Stansbury park, 12 August: 5.3 µg/m³ Tooele Tooele, 4 August: 7.1 µg/m³ Tooele, 5 August: 16.8 µg/m³ Tooele, 6 August: 11.0 µg/m³ Tooele, 7 August: 17.5 µg/m³ Tooele, 8 August: 28.3 µg/m³, 4.0× its usual 7.1 Tooele, 9 August: 10.2 µg/m³ Tooele, 10 August: 7.5 µg/m³ Tooele, 11 August: 17.0 µg/m³ Tooele, 12 August: 5.3 µg/m³ West Valley City West Valley City, 4 August: 8.2 µg/m³ West Valley City, 5 August: 8.0 µg/m³ West Valley City, 6 August: 8.2 µg/m³ West Valley City, 7 August: 15.3 µg/m³ West Valley City, 8 August: 27.8 µg/m³, 3.7× its usual 7.5 West Valley City, 9 August: 9.2 µg/m³ West Valley City, 10 August: 7.3 µg/m³ West Valley City, 11 August: 9.6 µg/m³ West Valley City, 12 August: 4.4 µg/m³ Salt Lake City Salt Lake City, 4 August: 5.9 µg/m³ Salt Lake City, 5 August: 9.0 µg/m³ Salt Lake City, 6 August: 7.5 µg/m³ Salt Lake City, 7 August: 14.3 µg/m³ Salt Lake City, 8 August: 27.3 µg/m³, 3.7× its usual 7.4 Salt Lake City, 9 August: 9.1 µg/m³ Salt Lake City, 10 August: 6.3 µg/m³ Salt Lake City, 11 August: 8.4 µg/m³ Salt Lake City, 12 August: 4.5 µg/m³ Baker City Baker City, 4 August: 12.7 µg/m³ Baker City, 5 August: 17.1 µg/m³ Baker City, 6 August: 15.0 µg/m³ Baker City, 7 August: 17.5 µg/m³ Baker City, 8 August: 25.3 µg/m³, 2.6× its usual 9.9 Baker City, 9 August: 21.0 µg/m³ Baker City, 10 August: 19.3 µg/m³ Baker City, 11 August: 21.8 µg/m³ Baker City, 12 August: 15.5 µg/m³ Weiser Weiser, 4 August: 12.0 µg/m³ Weiser, 5 August: no reading Weiser, 6 August: 16.8 µg/m³ Weiser, 7 August: 19.7 µg/m³ Weiser, 8 August: 24.0 µg/m³ Weiser, 9 August: 25.5 µg/m³, 2.4× its usual 10.8 Weiser, 10 August: 18.1 µg/m³ Weiser, 11 August: 19.6 µg/m³ Weiser, 12 August: 19.5 µg/m³ 4 Aug 5 6 7 8 9 10 11 12 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
Garden City Idaho, United States 3 8 August 6.8 15× Talent Oregon, United States 1 8 August 6.0 11× Medford Oregon, United States 2 8 August 6.3 10× Ashland Oregon, United States 1 8 August 6.1 9.2× Meridian Idaho, United States 2 8 August 8.3 9.0× Altamont Oregon, United States 2 7 August 6.3 7.3× Grants Pass Oregon, United States 2 8 August 4.4 6.9× Nampa Idaho, United States 2 8 August 9.7 6.5× Preston Idaho, United States 1 8 August 4.3 5.7× Pocatello Idaho, United States 2 7 August 5.9 5.0× Twin Falls Idaho, United States 2 7 August 6.6 4.8× North Ogden Utah, United States 1 8 August 6.6 4.7× Stansbury park Utah, United States 1 8 August 7.1 4.0× Tooele Utah, United States 1 8 August 7.1 4.0× Bend Oregon, United States 2 7 August 8.6 3.9× Smithfield Utah, United States 2 8 August 8.3 3.8× West Valley City Utah, United States 1 8 August 7.5 3.7× Salt Lake City Utah, United States 1 8 August 7.4 3.7× Burley Idaho, United States 1 7 August 8.4 3.5× Millcreek Utah, United States 1 8 August 9.1 3.2× Madras Oregon, United States 2 8 August 10.6 2.9× Prineville Oregon, United States 1 8 August 10.1 2.9× Redmond Oregon, United States 2 8 August 12.1 2.7× Baker City Oregon, United States 1 8 August 9.9 2.6× Weiser Idaho, United States 1 9 August 10.8 2.4×
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 52 of 151 episodes in the United States since our records began, by cities reached.
Eastern United States and Canada, June and July 2023 343 Northern United States and Canada, July 2026 327 United States and Canada, July 2023 322 Eastern United States and Canada, May and June 2023 317 North-eastern United States and Canada, 29 July to 9 August 2025 292 Northern United States and Canada, May and June 2025 247 United States and Canada, June 2023 195 North-western United States and Canada, August 2023 176 North-western United States and Canada, 4 to 22 August 2026 151 Northern United States and Canada, July 2025 139 Northern United States and Canada, June 2025 134 North-western United States and Canada, July and August 2026 118 Oregon, Idaho and Utah, United States, August 2024 25 Bars: cities reached; colour: the level of the episode's highest daily reading. All 151 .
Use this page SmogRank, Oregon, Idaho and Utah, United States, August 2024: 25 cities with PM2.5 at twice their usual or more, 7 to 9 August 2024, smogrank.com/episodes/2024-08-oregon-idaho-and-utah-united-states (accessed 5 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.
