Camp Fire, Nov. 8, 2018 10:45 am
Photo by NASA Goddard Space Flight Center

A wildfire is an unplanned fire that burns in a natural area such as a forest, grassland, or prairie. Wildfires are often caused by human activity or a natural phenomenon such as lightning, and they can happen at any time or anywhere. In 50% of wildfires recorded, it is not known how they started.

The risk of wildfires increases in extremely dry conditions, such as drought, and during high winds. Wildfires can disrupt transportation, communications, power and gas services, and water supply. They also lead to a deterioration of the air quality, and loss of property, crops, resources, animals and people.

Wildfires and volcanic activities affected 6.2 million people between 1998-2017 with 2400 attributable deaths worldwide from suffocation, injuries, and burns, but the size and frequency of wildfires are growing due to climate change. Hotter and drier conditions are drying out ecosystems and increasing the risk of wildfires. Wildfires also simultaneously impact weather and the climate by releasing large quantities of carbon dioxide, carbon monoxide and fine particulate matter into the atmosphere. Resulting air pollution can cause a range of health issues, including respiratory and cardiovascular problems. Another significant health effect of wildfires is on mental health and psychosocial well-being.


Wildfires or forest fires can have significant impact on mortality and morbidity depending on the size, speed and proximity to the fire, and whether the population has advanced warning to evacuate.

Wildfire smoke is a mixture of air pollutants of which particulate matter is the principal public health threat.

Infants, young child, women who are pregnant, and older adults are more susceptible to health impacts from smoke and ash, which are important air pollutants.  Smoke and ash from wildfires can greatly impact those with pre-existing respiratory diseases or heart disease. Firefighters and emergency response workers are also greatly impacted by injuries, burns and smoke inhalation.

Beyond fatalities, wildfires, and the resulting smoke and ashes, can cause:

  • burns and injuries
  • eye, nose, throat and lung irritation
  • decreased lung function, including coughing and wheezing
  • pulmonary inflammation, bronchitis, exacerbation of asthma, and other lung diseases
  • exacerbation of cardiovascular diseases, such as heart failure

Wildfires also release significant amounts of mercury into the air, which can lead to impairment of speech, hearing and walking, muscle weakness and vision problems for people of all ages.

More Information

Forest Management:

US Forest Service managing wildfire.

CalFire resource management.

Keeping the forest healthy.

The California Fire Safe Council helps regional, state, and national organizations in order to help California residents acquire the education, resources, and tools they need to be better prepared for wildfire:

The American Forest Foundation through a project called My Sierra Woods (MSW) is working with partners in northern California to support landowners in improving the health of their forests.  The SRWP is a member of the MSW Steering Committee.