As a series As large fires continue to burn in the Los Angeles area, blanketing neighborhoods in smoke and forcing thousands of people to evacuate their homes, air quality remains poor across many parts of the county.

Wildfire smoke is a mixture of water vapor, gases, and microscopic particles known as particulate matter. The smallest of these particles, known as PM2.5 because they have a diameter of less than 2.5 micrometers, pose the greatest risk to human health. It can penetrate deep into the lungs and sometimes enter the bloodstream. Earlier this week, PM2.5 around Los Angeles rose to “dangerous” levels, the highest warning in US Air Quality Index.

“Fire smoke is dangerous for everyone, especially when particulate matter is released in large quantities over long periods of time, like what’s happening in California right now,” said Zachary Rubin, a pediatrician in the Chicago area. and spokesperson for the American College of Allergy, Asthma, and Immunology.

If fine particulate matter is inhaled, it can cause inflammation in the body. Symptoms can vary from mild, such as burning or itchy eyes, runny nose, scratchy throat, and headache, to severe respiratory issues, including difficulty breathing, coughing, wheezing cough, fatigue, and chest pain. It can take anywhere from a few hours to days after exposure for symptoms to appear. In the most serious cases, it increases the risk of premature death.

Children, the elderly, pregnant women, and those with heart or lung conditions or a weakened immune system are at higher risk of developing severe side effects. But Rubin said it’s possible for anyone, regardless of their health status, to have respiratory effects from exposure to fire smoke.

“Any level of air pollution, including from wildfires, can be dangerous to your health,” said Laura Corlin, an environmental epidemiologist at Tufts University School of Medicine. How dangerous you are depends on many factors, including your current health status, your proximity to the fire, and the duration of exposure. “A good rule of thumb is the worse the exposure,” he said.

The composition of a wildfire can also have an impact on human health. Because of the California wildfires that engulfed homes and businesses, the region’s smoke is likely to contain chemicals released from synthetic building materials that are more toxic than those released from burning plants.

People in Los Angeles County and anywhere in the US can check airnow.gov to learn more about the current air quality in their area. As air quality can change easily during the day, you should always monitor the readings if there is a fire burning in your area, and try to limit your exposure to outdoor air if the quality is poor. the Duty of care The app is a great resource for checking if there are fires burning near where you are.

How to Protect Yourself and Others

“The lungs purify the air we breathe and send it to the heart, and the heart pumps it to the rest of the body,” said Shazia Jamil, a pulmonologist and professor of medicine at the Scripps Clinic and University of California, San Diego. Jamil helped develop a guiding for the American Thoracic Society on how to stay healthy during a fire.

He says that if someone is short of breath, wheezing, or has a high respiratory rate due to smoke inhalation, that can make the heart beat faster and worsen pre-existing heart problems. Even healthy people can experience chest pain and shortness of breath from inhaling smoke.