The cloak of wildfire smoke that has descended across huge swaths of Northern California is a visible reminder of air pollution’s health threats. For people at high risk for severe COVID-19 symptoms, the bad air presents a new challenge. For firefighters and others exposed to large amounts of smoke, the long-term effects are uncertain.

Kari Nadeau, MD, PhD, professor of medicine and of pediatrics and director of the Sean N. Parker Center for Allergy & Asthma Research, and Mary Prunicki, MD, PhD, the center’s director of air pollution and health research, study wildfire smoke’s effects on the heart, lungs and immune system. One of their current projects involves analyzing blood from current and retired firefighters, as well as members of the public, to see how smoke alters the immune system over time and how air purifiers and masks might lessen the impact (read more about their research).

Here, Nadeau, who is also the Naddisy Foundation Professor in Pediatric Food Allergy, Immunology, and Asthma, and Prunicki discuss health threats, preparedness and ongoing research related to wildfire smoke.

 1. What kind of health effects are you seeing from these fires? How are you studying them?

Nadeau: We are doing a comprehensive collection, via searches in the electronic medical record system of Stanford’s emergency department, of health-emergency data from the past few days compared to the time period prior to the wildfires. We are finding that there are increases in asthma, heart attacks and strokes during this week of wildfires compared to the week prior. People who are over 65 years of age have a higher chance of heart attacks and strokes even after two to three days of bad air quality due to wildfire smoke.

The smoke from wildfires goes through the lungs and the airways and can be absorbed into the blood. There are over 400 toxins associated with wildfire smoke, which have a multitude of bad effects on the body. In the blood, these toxins can activate the immune system and platelets and the lining of blood vessels. When this happens, the inflammation can induce clots which lodge in the heart or the brain vessels and cause heart attacks or strokes, respectively. Asthma can get worse with wildfire smoke because the smoke gets into the lungs and causes irritation and muscle spasms, which lead to wheezing and difficulty breathing.