Relevance

Ozone (O3) in high concentrations can cause health effects such as lung inflammation and other respiratory illness. Ozone can also cause damage to trees and plants at concentrations lower than the human health based ambient air quality standards. TRPA, federal and state standards have been adopted to protect human health. This indicator addresses the highest monitored O3 concentration averaged over every 1-hour for the calendar year.

Human and Environmental Drivers

Ozone is a secondary pollutant created by photochemical reactions between hydrocarbons (HC) and oxides of nitrogen (NOx) in sunlight. The primary sources of HC and NOx include in-basin mobile sources such as cars, trucks, boats, aircraft and off-road vehicles; biomass burning such as wood stoves, wildfires and prescribed burning; and consumer products such as solvents. Ozone is also transported into the basin to a lesser extent from populated areas surrounding the basin. The ambient concentration of O3 is highly dependent on meteorological conditions such as sunlight, temperature, wind speed, and mixing conditions. Typically, the greater the volume of sources such as increased traffic contributing to precursor gas concentration during optimal weather conditions, the higher the concentration of ozone.

EIP Indicators

• Miles of Pedestrian and Bicycle Routes Improved or Constructed

  Since 1997 EIP partners have collectively constructed or improved 193 miles of pedestrian and bicycle routes reducing the number of vehicle trips.

• 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

• TART Transit Operations 2025

  Projects like this that expand transit operations on the North Shore limit car exhaust in the Basin.

Monitoring Programs

• Ozone Monitoring

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