This indicator measures visibility on an "average" day in the urbanized area of South Lake Tahoe. Visibility measures the distance at which an object or light can be clearly discerned by the human eye. Sources of locally generated haze pollutants include entrained/suspended roadway particles, vehicle emissions, residential wood burning, campfires, prescribed fires, and wildfires. Some particles responsible for the degradation of regional visibility in the Tahoe Basin include dust and other pollutants transported into the Basin from areas as far as Asia. Regional programs such as increased street sweeping and work to improve forest health aim to increase sub-regional visibility. Sub-regional visibility is monitored at Lake Tahoe Community College as part of the national IMPROVE monitoring network. 

Status

Sub-regional visibility conditions at the old South Lake Tahoe site and current Lake Tahoe Community College site. 

Evaluation Map

Sub-regional visibility monitoring station at the Lake Tahoe Community College.

2019 Evaluation

Status
Considerably Better Than Target
Trend
Insufficient Data to Determine Trend
Confidence
Moderate
View Evaluation

Applicable Standard

AQ7: Achieve an extinction coefficient of 50 Mm-1 at least 50 percent of the time as calculated from aerosol species concentrations measured at the South Lake Tahoe monitoring site (visual range of 78 km, 48 miles).

Key Points

  • The South Lake Tahoe monitoring station was recently re-established. Compared to data from the 1990s, sub-regional visibility appears to have greatly improved.
  • Visibility on average days in the urbanized area of South Lake Tahoe is well within air quality standards.

Delivering and Measuring Success

EIP Indicators

  • Miles of Street Sweeping

    Since 2009 EIP partners have swept more than 61,000 miles of roadways within the Tahoe Basin reducing fine sediment particles from roadways entering the air and water.

  • Non-Compliant Wood Stoves Removed or Retrofitted

    This EIP performance measure tracks removal of polluting wood stoves to reduce local air pollution for human and ecosystem health.

Example EIP Projects

Monitoring Programs