Wildfire smoke contains fine particulates, commonly known as PM2.5, that are often unseen components of smoke and soot.
These fine particles come directly from wildfire smoke, and tend to be “more toxic than other sources of PM2.5” because wildfires burn everything, Dominici said. This includes various household materials, such polyvinyl piping and batteries, that produce toxic emissions when combusted.
The particulates are so small that they can be inhaled through your lungs and enter the bloodstream. Exposure can trigger short-term respiratory problems such as coughing, wheezing, difficulty breathing and asthma exacerbation, according to Dominici. Breathing in smoke can also irritate your sinuses, throat and eyes, according to the Centers for Disease Control and Prevention.
In more severe cases, exposure is linked with cardiovascular impacts — including heart attacks and stroke — as well as lung cancer and damage to cognitive functions.
The elderly face some of the greatest risk due to their body’s inability to fight against cardiovascular and respiratory inflammation caused by PM2.5, coupled with other conditions, Dominici said. Limited mobility could also increase risk.
“They may have less ability to move away from the area and be able to protect themselves,” Dominici said.
Young children, people with preexisting cardiovascular or respiratory disease or who are pregnant also face significant risks.
Race and socio-economic status can increase vulnerability. Research conducted by Harvard show that Black, Asian, Hispanic, Latino and low-income populations are exposed to fine-particulate pollution far more than people of other groups.
Often, lower-income individuals aren’t able to evacuate during wildfire season and can’t afford expensive filtration equipment to shelter in place, Dominici said. Many low-income individuals are front-line workers as well.
Map shows air quality effects of wildfires in Quebec, June 3, 2023
The National Ambient Air Quality Standard recommended maximum exposure to PM2.5 is an annual mean of 12 micrograms per cubic meter of air and 35 micrograms per cubic meter in a 24-hour period.
But experts believe that 35 micrograms per cubic meter daily is still too high.
In Dominici’s view, the federal government’s short- and long-term standards are not protective enough and “need to be lowered.”
“The evidence says that they should be as low as possible and that there is not a ‘safe’ level,” she added.
The Environmental Protection Agency recently proposed making the new annual recommendation between the range of 9 to 10 micrograms per cubic meter.
