MOUNTAIN AREA — Smoke from the Railroad and South Fork Fire burning in both Madera/Mariposa Counties, the Empire Fire burning in Mariposa County, the Pier Fire burning in Tulare County, and all other surrounding wildfires have the potential to affect air quality throughout the entire San Joaquin Valley and foothills above, prompting Air District officials to issue a health cautionary statement. Heat and high pressure will remain through the weekend, affecting air quality conditions.
Overnight winds may cause smoke to heavily impact the Air Basin, with the potential to increase both PM2.5 and ozone concentrations. The strong high pressure system parked over the Valley will trap pollution and cause air quality to deteriorate. Air officials are expecting these conditions to continue until early next week. The public should exercise caution until the fires are extinguished.
Under these weather conditions, there is potential for new fires to occur this weekend. Smoke from wildfires produces particulate matter (PM2.5), which can cause serious health problems including lung disease, asthma attacks and increased risk of heart attacks and stroke. People with existing respiratory conditions, young children and elderly people are especially susceptible to health effects from these pollutants. Air District officials urge residents to follow their doctors’ orders when exposed to wildfire emissions and stay indoors if at all possible.
Please be advised that the District’s Real-time Air Advisory Network (RAAN) monitors are designed to detect the fine particulates (called PM2.5 which are microscopic in size and not visible to the human eye) that exist in wildfire smoke. Ash particles are much larger in size and will not be detected by our monitors. Therefore an area may be experiencing ash impacts from these wildfires while the PM monitor reflects a moderate reading. If you can see or smell smoke or ash, which is an indication that you should be treating air quality conditions as “Unhealthy” (RAAN Level 4 or higher) and remain indoors.
Residents can check the District’s wildfire page at www.valleyair.org/wildfires for information about any current wildfires and whether they are impacting the Valley. Residents can also check the nearest air monitor to their location to determine localized air-quality conditions. Visit the Real-time Air Advisory Network to subscribe for free: www.valleyair.org/RAAN.
For more information, visit www.valleyair.org or call a District office in Fresno (559-230-6000), Modesto (209-557-6400) or Bakersfield (661-392-5500).
Photo by Dennis Spear from Deadwood looking toward Railroad Fire, Aug 29, 2017