Wildfires pollute the air with smoke, dust, ash. Here's how to protect yourself

Several parts of Southern California are currently under a windblown dust and ash advisory as deadly wildfires continue to burn across the region.

The advisory covers large sections of Los Angeles and Riverside and is expected to last until Wednesday evening, according to the South Coast Air Quality Management District.

Health experts and public officials have urged those impacted by the fires to protect themselves from air pollution carried by these winds by staying indoors, wearing protective equipment when needed and taking steps to purify air in the home.

“Predicting where ash or soot from a fire will travel, or how winds will impact air quality, is difficult, so it's important for everyone to stay aware of the air quality in your area, make plans and take action to protect your health and your family's health," Dr. Muntu Davis, health officer for Los Angeles County, said in a press release on Sunday.

“Smoke and ash can harm everyone, even those who are healthy. However, people at higher risk include children, older adults, pregnant individuals, and those with heart or lung conditions or weakened immune systems,” Davis continued.

Dangers of wildfire smoke

Wildfire and smoke contain particulate matter (PM), a mixture of solid particles and liquid droplets found in the air, according to the U.S. Environmental Protection Agency. Some are visible, such as soil and soot, but others are microscopic.

PM 10 and 2.5 are microscopic solid or liquid droplets, up to 30 times smaller than the diameter of a human hair. They can be inhaled and absorbed in the bloodstream, leading to serious health problems, the agency says.

“When you inhale [these pollutants], you're going to activate the inflammatory response in your lungs,” Dr. Jamie Rutland, a pulmonologist in California and volunteer medical spokesperson for the American Lung Association, told ABC News. “As the particles get smaller, they can travel down the lung and, just like oxygen, they can diffuse across the membrane to get into your bloodstream.”

Once in the bloodstream, a more systemic inflammatory response is activated that negatively impacts other organ systems including the heart, brain and immune system, Rutland said.

According to the EPA: “Fine particles are respiratory irritants, and exposures to high concentrations can cause persistent coughing, phlegm, wheezing, and difficulty breathing. Even in healthy people, exposures to fine particles can potentially lead to transient reductions in lung function, and pulmonary inflammation.”

The type of health effects a person experiences can depend on how much smoke and particulate matter a person is exposed to, how long the exposure lasts and individual risk factors such as socioeconomic status and underlying health conditions.

“We have to remember that kids under 5, people over 60, pregnant females -- these are the most vulnerable members of our population. These are the vulnerable members that even when they're healthy, they can get really sick really easily,” Rutland said.

Rutland warns that exposure to hazardous particulate matter after fires of this magnitude can last weeks to years depending on the conditions. He is urging people to frequently check the air quality index where they live, wear masks when needed, know their risk factors and get help if they experience severe symptoms.

“If you're having chest pain and you think it's either your lung or your heart, you also need to seek a medical attention," he said. "If the child starts coughing, if the child seems like they're in distress at all, you need to go seek medical attention.”

Use a high-quality filter and wear a mask

People under alerts should remain indoors as much as possible as well as keep windows and doors closed and sealed, according to the EPA.

This includes closing any doors to rooms inside the home that may have ventilation ducts connected to the outside, commonly found in laundry rooms and bathrooms.

The EPA says using a high efficiency filter, like a MERV 13 or higher, can help. Such filters can remove as much as 95% of particles that pass through it.

“Upgrading to a filter rated MERV 13 or higher can be especially important during smoky periods to effectively remove fine particle pollution from smoke in the indoor air,” the EPA states.

Fresh-air intake functions of central air systems should be closed or turned off, according to the EPA.

Portable air cleaners can be used alone or in addition to central air filtration, the EPA says. These are best used continuously in the room with you, according to Consumer Reports.

It’s recommended to change any air filter as soon as it’s indicated but, if that’s not possible, continue using the filter while there is air quality danger.

When outside, people should wear particulate respirators that have been tested and approved by the National Institute of Occupational Safety and Health.

The EPA says these masks have the words “NIOSH” and either “N95” or “P100” printed on them. These masks can also be worn inside a home if needed. Eye protection may also be necessary if outside.

Jade A. Cobern, MD, MPH, board-certified in pediatrics and general preventive medicine, is a medical fellow of the ABC News Medical Unit.