Millions of Americans are facing hazardous air this week as a sprawling smoke emergency spreads across several western US states.
The National Weather Service (NWS) has issued air quality alerts for wide areas of Idaho, Montana, Nevada, Oregon and Washington, warning residents to protect themselves while dangerous wildfires burn across the Pacific Northwest.
In central and eastern Oregon, at least 6,000 people were placed under a “Go Now!” evacuation order Tuesday night after lightning storms ignited major fires across the region. Officials said fires are now burning across more than 1.5 million acres in the state.
Large wildfires in Oregon and Washington are pushing vast plumes of toxic smoke through the region, driving pollution levels into the “unhealthy” and “very unhealthy” categories across all five affected states.
NWS officials warned: “Pollutants in smoke can cause burning eyes, runny nose, aggravate heart and lung diseases, and aggravate other serious health problems.”
“Limit outdoor activities and keep children indoors if it is smoky. Please follow medical advice if you have a heart or lung condition.”
Wildfire smoke carries fine particulate matter known as PM2.5 — microscopic toxic particles small enough to enter human tissue and trigger breathing problems.
Major cities in Montana and Idaho are expected to see some of the worst smoke conditions Wednesday, including Boise and Twin Falls in Idaho, as well as Billings, Missoula and Great Falls in Montana.

Wildfire smoke is blanketing five states in the Pacific Northwest as over one million acres burn

Air quality monitors have warned that pollution levels have reached the ‘very unhealthy’ zone in multiple western states
The US Environmental Protection Agency (EPA) has connected breathing in PM2.5 to multiple health issues, including aggravated asthma, decreased lung function, irregular heartbeat, heart attacks and premature death for those with heart and lung disease.
Typically, the Air Quality Index (AQI) is measured on a scale from 0 to 500: ‘good’ (0–50) carries little risk, ‘moderate’ (51–100) may affect sensitive individuals, ‘unhealthy for sensitive groups’ (101–150) poses increased risk and ‘unhealthy’ (151–200) impacts everyone, limiting outdoor activity.
According to live air quality-tracking website IQAir, levels along the Oregon-Idaho border have surpassed 200 in multiple areas, including in Meridian, Idaho, where the pollution levels reached 234 by 10am ET on Wednesday.
If outdoor air quality reaches the 300 to 500 ‘hazardous’ zone or surpasses that mark, the EPA warns that everyone should avoid all physical activity outside.
The air quality alerts in Nevada, Montana and Washington are expected to last into the afternoon on Wednesday.
However, several counties across Idaho and Oregon will remain under air quality warnings through Friday, while others are expected to be in the danger zone until the fires are brought under control.
Oregon National Guard Lieutenant Colonel Nathan Edgecomb said in a statement: ‘We expect this to be a long and hard fire season, so we’re preparing for the worst.’
NWS noted that those expected to be affected the most by the wildfire smoke include children under 18, the elderly, pregnant women and people with asthma or those who have difficulty breathing.

Wildfires have triggered evacuations in central and easter Oregon for thousands of residents

Pictured: Emergency responders in Oregon attempt to put out the ‘Bench Fire’ from spreading in Warm Springs on July 25
Some with diabetes, heart problems or pre-existing health conditions and people who have high exposure from working outside or exercising outdoors may also be affected.
This is a breaking story. More details to follow.