Wildfire Smoke and Air Quality
The best indicator of air quality related to wildfire smoke is particle pollution level. This measurement is often displayed as: Particles (PM2.5). This represents the concentration of fine particles in the air that are 2.5 micrometers or smaller (these can only be seen with a microscope). Park staff is not able to predict if conditions will be smoky for your trip. We encourage you to use the resources below to view current conditions and forecasts to inform your plans.
During summer, smoke from wildfires in and around Lassen occasionally degrade park air quality. Fires and related smoke impacts can continue to occur in the fall and sometimes as late as December in a dry year. The park and its features and facilities rarely close for smoke impacts alone. However, visitors are are encouraged to reduce time spent outdoors in smoky areas.
Smoke and Your Health
Learn more about Reducing Your Smoke Exposure, Wildfire Smoke and Your Health, and How to Protect Yourself from Wildfire Smoke (video)
Air Quality Monitoring
Lassen Volcanic National Park is a Class I airshed, which receives the highest level of protection under the law. Lassen participates in four air quality monitoring networks (CASTNET, IMPROVE, NADP/NTN, GPMP). Park scientists visit air quality monitoring stations in the Manzanita Lake Area once a week to prepare rain or snow samples for the lab, change filters, and check the conditions of sensors. Learn more about air quality in the park here.
Visibility is our ability to clearly see color and detail in distant views. Haze results from air pollutants, such as fine particles that absorb and scatter sunlight. Some haze occurs naturally due to dust, fog, and wildfire smoke. Unnatural haze is caused by air pollution from industry and motor vehicles. Visibility has improved at Lassen since monitoring began in the late 1980s. The clearest days have become clearer. In the last decade, the haziest days have become slightly less hazy. The estimated visual range on mid-range days was about 175 miles.
Last updated: September 14, 2020