Oppressive heat and intense wildfires in the Pacific Northwest and northern California created conditions for severely degraded, hazardous regional air quality on Friday morning, August 13, 2021.

In a week in which temperatures in normally mild Seattle, Washington and Portland, Oregon either reached or neared 100°F, equally hot communities to the east bore the brunt of toxic wildfire smoke from local fires.¹

Further south, the massive Dixie Fire in northern California sent clouds of smoke north, leading to exceptionally poor air quality as far away as Bend, Oregon.

Nations share border, wildfire smoke hazards

Smoke from almost 300 wildfires in British Columbia is combining to endanger lives on both sides of the U.S.-Canadian border.²

On the morning of August 13, many small towns in British Columbia recorded “hazardous” air quality. Air quality alerts were issued for parts of British Columbia, Washington State, and Idaho.^3,4

Pictured: Air quality in British Columbia was hazardous in numerous mountain communities. Source: IQAir

While no amount of air pollution is safe for human health, “hazardous” air quality is the most life-endangering measurement and has no designated ceiling for measurement. As measured on the U.S. air quality index, a “hazardous” measurement is a reading of 301 or higher for a major air pollutant.

The main and most hazardous pollutants found in smoke are PM2.5 (airborne particulate matter that measures less than 2.5 microns in diameter) and ultrafine particles (PM measured at less than .1 micron in diameter). Ultrafine particles are the most dangerous of all pollutants, as they are so small that after inhalation, they can enter the bloodstream and harm all bodily organs.

Pictured: Eastern Washington State, northern Idaho, and British Columbia registered “unhealthy” to “hazardous” air quality across numerous communities. Source: IQAir

On August 13, air quality measurements ranged from “unhealthy” to “hazardous” in most Pacific Northwest communities, with some of the most dangerous ratings recorded in:

Kelowna, British Columbia
Vernon, British Columbia
Kamploops, British Columbia
Castlegar, British Columbia
Salmon Arm, British Columbia
Chilliwack, British Columbia
Spokane, Washington
Yakima, Washington
Winthrop, Washington
Coeur d'Alene, Idaho
Lewiston, Idaho

Although larger cities like Boise, Seattle, Portland, and Vancouver, British Columbia escaped the worst of air quality measurements, there was still widespread poor air quality measured in all four metropolitan areas.

Pictured: Wildfires in the Pacific Northwest and northern California fueled “very unhealthy” and “hazardous air quality conditions on 13 August. Source: IQAir

Dixie Fire smoke covers two states

Further south, smoke from the Dixie Fire – the largest single fire in California history – carried “hazardous air quality across northern California and into Oregon.

The worst air quality in the United States was recorded in Weaverville, California, where the air quality index was measured at 601.

Pictured: Winds carried wildfire smoke from the Dixie Fire north through California and into southern Oregon. Source: IQAir

Other impacted communities included:

• Redding, California
• Mount Shasta, California
• Klamath Falls, Oregon
• Medford, Oregon

The takeaway

July, 2021 was the hottest month ever recorded.⁵ Heat, drought, and dry ground cover create ideal conditions for extreme wildfires – and the bigger the fire, the more smoke generated.

Because human-caused climate change is resulting in longer, more intense wildfires, it’s important to prepare for smoke and poor air quality in the home, workplace, and outdoors. Be aware of air quality in your neighborhood by using an air quality monitor.

If air quality is poor, keep doors and windows closed and turn on anair purifier for wildfire smoke.

When air quality is “unhealthy,” “very unhealthy,” or “hazardous,” the general public is very likely to feel immediate and harmful affects from outdoor smoke. If it is unavoidable to go outside, wear an air pollution mask.