This page displays the latest information and links from Yosemite's air quality and smoke monitoring network. Also, visit a general air quality webpage and general smoke page.

Air Quality Alerts:  None at this time.
Air Quality Advisory: None at this time (See NPS advisories from a nationwide park list).

• Fire Activity in Yosemite: On Oct. 16, 2009, Yosemite declared the end of the year's fire season. View maps regarding the 2009 season, including details on the Big Meadow Fire.

 What's This View? Enlarge this current view from Yosemite's Turtleback Dome, at 5,266 feet in elevation, looking west over the Merced River Canyon toward the Central Valley. Ozone and meteorological data (temperature, humidity, and winds, for example) are also posted at this link. For additional Yosemite webcams, see below.

Fine Particles and Smoke: Mountain campgrounds and other low-lying, flat areas can have significant campfire activity. Nighttime and early morning inversions can trap and concentrate fine particles from those campfires near the ground, creating conditions that are potentially unhealthy for individuals with respiratory and/or pulmonary ailments. Locally heavy smoke might also be found in the vicinity of prescribed or wildland fires that occur every year in the park. Particles are usually at their highest concentration late at night through early morning. Yosemite's fire management program works to minimize such impacts while protecting our fragile fire ecology. You might also want to check out Yosemite's fire history map to see where fires (and their smoke) commonly occur in Yosemite.

Click for current particulate matter levels.

View fine particle levels from the Yosemite Valley Visitor's Center. Graph displays data for the past several days.

Mobile Smoke Monitoring: You can see fine particle/smoke levels in near real-time on the Interagency Real Time Smoke Monitoring web site, which includes both of Yosemite's mobile smoke monitors. Once on the page that lists the mobile monitors, look at the far right column to link to both of the park's monitors. Note that the graphs that appear only present the past 24 hours of data. To access data more than 24 hours old, click on the “data details” button to the left of the graph. A screen will appear that allows the user to enter any date in the field to see what measurements, if any, were produced on a given date or range of dates. No instruments are currently deployed for the purposes of smoke monitoring--check back May 2010!

Ozone: Because ozone pollution near the ground is usually only a concern on hot, sunny days, the ozone "season" runs May through September. In the Yosemite frontcountry near ridgetops (like Turtleback Dome), ozone is often (30-40 days per year) found at levels unhealthy for sensitive individuals (asthmatics or others with respiratory ailments). In sheltered areas like the Yosemite Valley Schoolyard and remote, high elevations areas like Tuolumne Meadows, ozone is usually much lower, rarely unhealthy even on most polluted of days.

Highest levels of ozone on a given day usually occur in late afternoon and evening. If you have a respiratory condition, such as asthma, consult a doctor before exercising strenuously in areas where and during late afternoon periods when high ozone might occur. (See current ozone data and the ozone forecast below.)

Click for current ozone data at School Yard.

View ozone levels from the School Yard monitor in Yosemite Valley. Graph shows data for the past several days.

Click for current ozone data at Turtleback Dome.

View ozone levels from the Turtleback Dome monitor at 5,266-foot elevation. Graph shows data for the past several days. 

Coming soon: Ozone levels at Glacier Point.

Ozone and Smoke Forecast (Experimental): View a 48-hour ozone prediction from NOAA's National Weather Service. Specifically for:

• Yosemite Valley
• Hetch Hetchy
• Tuolumne Meadows
• Wawona
• El Portal

Note that these products are experimental and can be unreliable.

General Air and Weather Information

• Any time unhealthy levels of smoke occur, people can protect themselves by staying indoors or moving away from impacted areas. It is also a good idea to protect indoor air quality by closing all doors and windows and, if possible, setting ventilation systems to re-circulate air. Anyone with respiratory ailments, young children and older adults should limit exposure to smoky air by staying indoors or temporarily seeking areas with cleaner air. View the EPA's AIRNow site for general air quality information and maps depicting Air Quality Index values for the entire United States (includes local forecast and conditions).
• View current NPS park sites' ozone and weather data through monitoring graphs in real time. Select a monitoring site from Shenandoah in Virginia to Mount Rainier in Washington.
• View the National Weather Service forecast for the Yosemite area.

NASA

Click to see today's NASA satellite imagery of the Yosemite area.

View Online Tools to Locate a Fire Nearby

• View high resolution, color (MODIS) satellite imagery of the Yosemite area (2 images per day, afternoon).
• View lower resolution, black and white GOES image (from a satellite in geostationary orbit) of the Yosemite area (updated every 15 minutes).
• View daily maps of smoke plumes from current fires across the entire North American Continent, courtesy NOAA's Hazard Mapping System (HMS) fire and smoke product.
• Download fire maps and fire perimeters from GeoMAC’s (Geospatial Multi-Agency Coordination Group) federal mapping tools.
• Get specific fire information on current Sierra Nevada fires from the Sierra Wildland Fire Reporting System.

Park Webcams: View current images below or on the webcams web page for more choices.

 View from Turtleback Dome (Yosemite Association)

 View from Ahwahnee Meadow (Yosemite Association)

 View from Tioga Pass (Scripps Institute/UCSD)