Understanding Ozone
Ozone is a gas that occurs both in the Earth's upper atmosphere and at ground level. In the upper atmosphere ozone is “good” and protects us from the sun’s harmful ultraviolet (UV) rays. At ground level, ozone is “bad” and is an air pollutant that is harmful to breathe and that damages crops, trees and other vegetation. It is a main ingredient of smog.
Hot weather and sunlight interacting with oxides of nitrogen (NOx) and volatile organics (VOC) cause ground-level ozone to form in harmful concentrations in the air. Emissions from oil and gas drilling and motor vehicle exhaust are thought to be the main sources of NOx and VOC, with gasoline vapors and chemical solvents being lesser sources.
Many urban areas tend to have high levels of "bad" ground-level ozone, but even rural areas are subject to increased ozone levels because wind carries the pollutants that form ozone hundreds of miles away from their original sources.
Local Ozone Levels
Located near the intersection of Highway 82 and Cemetery Lane, the City’s ozone monitor will help determine if levels in the Aspen area are below EPA’s standard of 75 ppb, an analysis that will require three years of data. In the near-term, if levels approach the EPA standard, staff will take action by cross referencing weather, traffic and oil and gas data in light of the new monitor’s results. This information will allow officials to determine what actions, if any, are needed to reduce ozone levels. View last month's ozone levels.
The highest ozone level ever measured on Colorado’s Western Slope was recorded on Aspen Mountain in the summer of 2007. However, more research must be done to determine from where the ozone originates. Because ozone has serious health effects, we need to find out if there are high levels in town. This is why the City of Aspen has begun monitoring ozone levels, and will work with the US Forrest Service to compare Aspen’s levels with those from their nearby monitors.
Breathing ozone can trigger a variety of health problems including:
- Chest pain
- Coughing
- Throat irritation
- Congestion
- Worsening of bronchitis, emphysema, and asthma
Ground-level ozone (considered "bad") also can reduce lung function and inflame the linings of the lungs. Repeated exposure may permanently scar lung tissue. In Pitkin County, there are approximately 1,200 asthma cases (children and adults with asthma; taken from 2005 American Lung Association report) and 4.3 hospitalizations per 10,000 per year related to asthma (Health Statistics Section, Colorado Department of Public Health and Environment, May 2003.).
Please contact Jannette Whitcomb at 970-920-5069 with any ozone questions.