Indicator
3-Year Average of the 4th Highest 8-hour Average Concentration of Ozone
2015 Evaluation
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2015 Evaluation
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Status
At or Somewhat Better Than Target
Trend
Moderate Improvement
Confidence
High
Evaluation Map
aq oz 3 yr 4th highest.jpg
Description

Ozone monitoring locations in the Lake Tahoe Basin.

Rationale Details
Of all the monitoring stations where recent data is available, the
highest 3-year average of the 4th-highest daily maximum ozone concentration was 0.064 ppm in Incline Village, 85 percent of the standard (Campbell 2015). Therefore, a status of “somewhat better than target” was determined. The indicator has been in attainment at all monitoring locations since 1993.
The trend line for all monitoring stations since 1986 shows a decrease of 0.0004 ppm per year, a decrease of 0.53 percent per year in relation to the standard of 0.075 ppm (Campbell 2015). Therefore, a trend of moderate improvement is determined.
Confidence Details
High. There is high confidence in the status determination because data is collected using federal reference methods (EPA 2011a), are subject to quality assurance requirements, and are collected continuously across the Region since 1975.
High. Confidence in the trend is high with a confidence in a trend of 99 percent (P = 0.01)
Outcomes
Programs and Actions Implemented to Improve Conditions
Regional, state and federal emission standards for motor vehicles, motorized watercraft, gas appliances, and woodstoves. Transportation infrastructure improvements such as more efficient intersections, sidewalks, and bicycle infrastructure development. Public transportation systems. Regional and state restrictions on prescribed burning days. Restricted development of “drive-up window” commercial uses.
Effectiveness of Programs and Actions
Existing programs and actions implemented are effective based on the long-term indicator data, which shows that the standard has not been exceeded in the years that monitoring occurred.
Interim Target
Target Attainment Date
Recommendations
Analytic Approach
Regional, state and federal emission standards for motor vehicles, motorized watercraft, gas appliances, and woodstoves. Transportation infrastructure improvements such as more efficient intersections, sidewalks, and bicycle infrastructure development. Public transportation systems. Regional and state restrictions on prescribed burning days. Restricted development of “drive-up window” commercial uses.
Monitoring Approach
Existing programs and actions implemented are effective based on the long-term indicator data, which shows that the standard has not been exceeded in the years that monitoring occurred.
Modification of the Threshold Standard or Indicator
No changes recommended
Attain or Maintain Threshold
No changes recommended
Additional Figures and Resources

No photos available.

No documents available.