Air Pollution: Ozone
Pollution from Commuters Poses a Further Threat
Why is it important?
Ozone, while a natural and beneficial environmental component in the upper atmosphere, is a harmful air pollutant when it appears in the lower atmosphere. Health hazards range from itchy eyes and throat or chest pain to long-term lung damage.16 Tree and plant species also suffer from concentrated ozone levels.17
The two primary causes of lower atmosphere ozone are motor vehicle emissions and the reflection of the sun on rock or concrete. Both instances result in the breakdown of chemicals and production of harmful ozone. Air movement from the Sacramento and San Joaquin valleys particularly affects ozone concentration in the Sierra Nevada, especially in the North Central and South Central Sierra. The number of air monitoring stations has increased in the last decade, producing more accurate data. The table represents an average of all reporting stations for each subregion.18
How are we doing?
The North and East Sierra have few days when state ozone standards are exceeded. In the North Central and South Central Sierra, state ozone standards are exceeded by at least ten days in most years. The problem is slightly worse in the North Central during most years because of added pollution sources from travelers on Interstate 80 and urban areas.
16 California Department of Health Services. Retrieved May 9, 2005 from http://www.cal-iaq.org/o3_fact.htm
17 Centers for Water and Wildland Resources. University of Califiornia, Davis. June 1996.
Summary of the Sierra Nevada Ecosystem Project Report. Retrieved May 9, 2005 from http://ceres.ca.gov/snep/pubs/web/PDF/exec_sum.pdf
18 http://www.cal-iaq.org/o3_fact.htm
