9/12/2013 Rim Fire Air Quality Report

As air quality impacts from the Rim fire continue to diminish over the next several days, this report and the extended report will be replaced by a less formal informational update, posted as needed in the event that a significant impact is forecast.

Air Quality Report                                                          Thursday, September 12, 2013

Rim Fire, Stanislaus National Forest

Yesterday, September 11, 2013

The Rim Fire burned approximately 250 acres, almost entirely within the containment lines. It is currently 255,560 acres. Smoke production is primarily the result of heavy fuels that can continue to burn for several days within the fire area. Cloud cover and higher humidity helped to moderate fire activity. Most areas saw improved air quality from the previous days.

Thursday, September 12, 2013

Light downslope winds and a moderate inversion caused smoke to drain down the Clavey and Tuolumne River Drainages. Smoke impacts in the communities of Pinecrest, Columbia, Groveland, Greeley Hill, La Grange, El Portal, and Mariposa will be about the same as yesterday reaching their highest intensity early in the day and improving by afternoon. With transport winds still fairly light smoke impacts will remain localized. Evening impacts can be expected again for Tuolumne Meadows and Yosemite Valley with northwest ridgetop winds forecast. Diurnal upslope/upcanyon flows will be the dominant winds. A slightly chance of thunderstorms over the Sierras again today could aid smoke dispersion some in the late afternoon. Easterly winds will remain fairly light again tonight keeping impacts localized and probably not extending into the San Joaquin Valley.

Friday, September 13, 2013

Similar morning impacts can be expected in areas where the inversion will cause smoke to settle. Transport winds may be a little lighter, taking longer to clear smoke from foothill communities. Afternoon thunderstorm chances are lower than for Thursday. Northwesterly ridgetop winds will continue to send smoke toward the Yosemite region, which is likely to settle in the Tuolumne Meadows and Yosemite Valley basins in the evening. Nighttime easterlies will strengthen a bit, possibly moving smoke a little further into the San Joaquin Valley.

Long term Outlook

Conditions remain very similar Saturday, but start to transition on Sunday into Monday as a low pressure trough moves through. Winds will become southwesterly and temperatures decrease probably beginning sometime Sunday and lasting into early next week. This should give the areas south and west of the fire some clean air, and depending on the amount of remaining emissions, could return some smoke to areas north and east of the fire.

Follow the links in the following table to view real-time air quality monitoring data for each site.

Site	24-hour Avg PM2.5 (µg/m3)	3-hour Max PM2.5 (μg/mᵌ)	Level of Health Concern	Meaning	Actions to Protect Yourself	Forecast For Thurs. Sept 12, 2013
	Yesterday, Sept. 11
Reno S. Lk. Tahoe Carson City Mariposa La Grange	5 10 10 12 9	14-11:00 20-13:00 17-19:00 27-12:00 16-21:00	Good	Air quality is satisfactory and poses little or no health risk	None	Reno S. Lk. Tahoe Carson City Bear Valley Markleeville Minden
Markleeville Minden Bear Valley Greeley Hill El Portal Columbia Yosemite Vly	14 17 25 15 13 23 33	54-19:00 28-12:00 51-12:00 45-12:00 22-06:00 66-12:00 88-22:00	Moderate	Air quality is acceptable for most. There may be moderate health concern for a small number of sensitive people.	Unusually sensitive people should consider reducing prolonged or heavy outdoor exertion.	Mariposa Columbia La Grange Greeley Hill El Portal
Groveland Tuol. Mdws	50 53	244-10:00 109-23:00	Unhealthy for Sensitive Groups	Members of sensitive groups may experience health effects.  The general public is not likely to be affected.	People with heart or lung disease, children and older adults should reduce prolonged or heavy outdoor exertion.  Everyone else should limit prolonged or heavy exertion.	Yosemite Vly Groveland Tuol. Mdws Tuol. City Pinecrest
Pinecrest Tuol. City Drew Mdw ICP	61 84 99	152-13:00 274-11:00 301-09:00	Unhealthy	Everyone may begin to experience more serious health effects.	The following groups should avoid all physical outdoor activity: People with heart or lung disease, children and older adults.  Everyone else should avoid prolonged or heavy exertion.	Drew Mdw ICP

Air Quality Index (AQI) ratings are derived based on the recommendations found in Wildfire Smoke: A Guide for Public Health Officials.

For more information visit:

California Smoke Information Blog: http://northcasmoke.blogspot.com/