The wildfires in Northern California have grown so intense that the smoke can be seen hundreds of miles away from .
As a result, many people, even those dozens of miles away from flames, are at risk for asthma attacks, respiratory distress, and cardiac events due to the increased air pollution.
This week, said the fires had led to “unprecedented” levels of air pollution, which “due to active wildfires and changing wind patterns, air quality could be impacted for many days to come.”
In San Francisco, the smoke and haze led some residents to wear masks to protect themselves from the smoke.
Dr. Robert Blount, assistant professor of pulmonary pediatric and adult medicine at the University of California San Francisco, said if people can smell or see smoke they should take steps to protect themselves.
“If there's enough smoke that you can see it or smell it… then it's a dangerous level,” he told Healthline.
Children, the elderly, and people with lung or cardiac conditions are at the highest risk of developing symptoms, Blount explained.
“People need to be pretty careful about heavy smoke exposure,” he said.
He added that due to children’s small size, “they get a higher dose of the air pollution than adults.”
Dr. Naveena Bobba, the director of public health emergency preparedness and response at the Department of Public Health in San Francisco, said that if people start to have symptoms related to the smoke they should stay inside and seek out buildings with filtered air.
“They should also go indoors to a place that has a good HVAC system,” Bobba told Healthline.
If smoke or haze makes its way indoors, Bobba advises running an air conditioner to try and keep out the worst of the pollution. She also said air filters can help clean out the air, if a person doesn’t have an air conditioner.
As a last resort, Bobba said people can head to a newer building like a mall or movie theater to stay out of the polluted air. has set clean air shelters, where the air is being filtered.
“Good hydration is also very important so drinking lots of water [can help],” she added.
A mask can protect against smoke
For extra protection, special face masks called respirators can help.
These masks can provide protection from the small microscopic particles in smoke that can damage the lungs.
The only certain masks will work and other common types of face masks, like surgical masks, won’t filter out the harmful particles.
“Wildfire smoke has a higher proportion of particulate matter in the air — so solid matter — that can be filtered out,” Blount said. As a result, these masks, “can be very effective” at keeping out pollution.
Those who want extra protection from smoke can use the “respirators” or masks that are certified by the National Institute for Occupational Safety and Health (NIOSH).
The only types of masks that should be used are labeled with N95 or P100.
The California Department of Public Health explained that the filter material rated 95 will capture “at least 95 percent of very small particles.”
The filter material rated 100 filters out “at least 99.97 percent.”
The California Air Resources Board also explained that people with facial hair cannot get an appropriate “seal” around the face to ensure there isn’t dangerous particles being inhaled.
Without the masks or other protection, microscopic particles from smoke can travel through the lungs to exacerbate respiratory disease like asthma.
It can even raise the risk of cardiac events such as heart attacks or strokes.