Wildfire Smoke and Health

Wildfire smoke is a mixture of gases and particles primarily from the burning of trees and plants. In the case of fires that enter nearby communities, additional pollutants are emitted from the burning of human-made materials and structures. Of these air pollutants, fine particulate matter, also called particle pollution or PM_2.5, is the biggest threat to your health. Even if you breathe smoky air for only one day, it can affect your health. 

Most healthy people recover quickly from wildfire smoke exposure and will not experience immediate severe or long-lasting health effects. However, some groups of people—including children, older adults, pregnant women, people with heart or lung disease, and people with higher exposures, such as outdoor workers—are at higher risk of experiencing health effects. This page explains how wildfire smoke can affect your health and what you can do to reduce your risk of experiencing health effects. 

On this page: 

• Basics of Wildfire Smoke Exposure
• Wildfire Smoke Exposure and Health Effects
• How to Reduce Your Risk of Experiencing Health Effects
• Resources 

Basics of Wildfire Smoke Exposure 

The types of health effects that can occur in response to wildfire smoke exposure depend on how much smoke you are exposed to and how long the exposure lasts. Wildfire smoke exposures can occur over a short time (e.g., a few hours, a single day, up to a few days) or over a longer time (e.g., weeks, multiple times within a year, across years). These longer wildfire smoke exposures vary in frequency (how often smoke occurs), intensity (how much smoke occurs), and duration (how long smoke occurs). 

Wildfire Smoke Exposure and Health Effects

Most of what is known about the health effects of wildfire smoke comes from studies that examine short-term exposures (i.e., over a day or up to a few days). The health effects associated with short-term wildfire smoke exposure builds on the decades of scientific evidence on short-term PM_2.5 exposures. Less is known about the health effects from longer duration wildfire smoke exposures (including persistent, repeated, episodic, and cumulative exposures) that vary within and across years. This is why it is always a good idea to take exposure reduction measures when smoke is in the air.

Short-term wildfire smoke exposure can lead to: 

• Headaches
• Eye irritation 
• Respiratory symptoms
  • Coughing
  • Increased phlegm
  • Wheezing
  • Difficulty breathing
  • Chest tightness
• Respiratory effects
  • Bronchitis
  • Reduced lung function
  • Asthma exacerbation and aggravation of other lung diseases
  • Emergency department visits and hospital admissions for respiratory conditions
• Cardiovascular effects
  • Heart failure exacerbation
  • Heart attack
  • Stroke
  • Emergency department visits and hospital admissions for cardiovascular conditions
• Birth outcomes
  • Preterm birth
• Premature death