This week, communities across the Midwest and eastern parts of the U.S. are experiencing the effects of smoke from wildfires in Canada. Parts of Kentucky reached unhealthy levels in the air quality index (AQI).

David Mannino, MD, (DM) is a professor of internal medicine and physician specializing in pulmonary disease. Christopher Waters, PhD, (CW) is the Dr. Donald T. Frazier Professor of Physiology and a seasoned researcher studying acute lung injury.

They share their expertise, from the clinical and scientific side, regarding the risk of exposure to air pollution and what high-risk individuals can do to be safe on days with poor air quality.

Q: How does exposure to air pollution impact respiratory health, particularly for individuals with pre-existing lung conditions?

DM: The air quality is being affected by fine particulate air pollution (particles less than 2.5 microns). For reference – a human hair is about 70 to 80 microns. These particles can be irritating to people with respiratory issues such as asthma or chronic obstructive pulmonary disease (COPD). At the levels we are seeing, even people without lung disease might notice symptoms like a sore throat, eye irritation, or a cough.

The biggest risk is those with lung disease is that this could lead to a flare-up or exacerbation. While most people can treat this by adjusting their medication dose, there is the potential this could result in an emergency room visit or hospitalization.

CW: The first thing to recognize about the smoke from wildfires compared with typical air pollution is that the wildfire smoke contains higher concentrations of small particulate matter (known as PM2.5) that can travel deeper into the lungs and can be very harmful. In the short term, these small particles can cause inflammation, constriction of airways, coughing, and shortness of breath in otherwise healthy individuals, but can also substantially exacerbate symptoms in people with asthma, bronchitis, COPD, or other respiratory diseases.

Repeated long-term (daily) exposure to air pollution containing small particles has been shown through both experimental and epidemiological studies to negatively impact lung health, particularly in children. The repeated exposures lead to chronic inflammation and injury in the lungs. These effects contribute to increased susceptibility to lung infections, increased emergency department visits and hospitalizations related to respiratory symptoms, decreased lung function, and increased cardiovascular disease.

Q: Are there certain groups of people who are more vulnerable to the adverse effects of air pollution?

DM: In general, the more sensitive groups tend to be the very young (infants), the very old (who frequently have other diseases that make them vulnerable), and people with underlying respiratory diseases such as asthma or COPD. People with heart disease (like heart failure) may also be more sensitive.

Q: What preventive measures or precautions would you recommend for individuals on days when the AQI is high to minimize the impact on their respiratory health?

DM: For those who are sensitive, staying inside on high pollution days is recommended. People with asthma and COPD should have an action plan to deal with increasing respiratory symptoms (such as using their rescue inhaler). If they do not have this, they can discuss with their health care provider.