Particulate matter consists of very small liquid and solid particles from a variety of human and natural sources. When inhaled, fine particles can be particularly harmful to children, active adults, and the elderly. Particulate matter also deposits in the lake and results in reduced clarity. Ambient concentrations of PM2.5 and PM10 are generally low in Tahoe and are not a human health concern. Wildfires inside and outside can cause PM concentrations to increase to levels of concern for human health. Sources of fine particulate matter in the Tahoe Basin include resuspended road dust, wildfires, prescribed burning, wood burning (residential and campfires). Regional programs such as increased sweeping, old wood stove replacement, and forest fuels project to prevent wildfire aim to reduce particulate matter.

Indicators

THRESHOLD CATEGORY REPORTING CATEGORY INDICATOR
THRESHOLD CATEGORY REPORTING CATEGORY INDICATOR

The threshold evaluation assigns a status to an indicator relative to the adopted standard. As shown on the icon legend below, the background color of the reporting icon communicates the indicator “status” or estimate of current condition. For numerical standards, the status of an indicator is classified into “better” or “worse” categories based on the percent divergence of the current indicator value from the standard or interim target. For most indicators, the current value is taken directly from the value recorded in the most recent year. In some cases, the average value calculated from all data collected during the evaluation period is used. When an average value is used, it is noted and explained on the indicator evaluation page for that specific evaluation year.  

Note: Thresholds reported as "Implemented" refer to thresholds that were adopted as policy guidance in the development of the Regional Plan. In these cases, the subject policies, ordinances, or environmental protections have been incorporated into the TRPA Regional Plan and TRPA Code of Ordinances.