What is ozone?
What are current ozone concentrations, and where can I find more information about ozone?
What are the human and environmental health effects of ozone?
What is the ozone standard?
Where is ozone monitored in the Colorado Springs region?
What are the ozone trends in the Colorado Springs area?
What is the status of the proposed revisions to the National Ambient Air Quality Standards for Ozone?

What is ozone?
Ozone is a component of smog and the “brown cloud” and causes health problems. Unlike carbon monoxide, ozone is not emitted directly as a pollutant but forms when sunlight causes a chemical reaction between hydrocarbons (VOCs) and nitrogen oxide. VOCs are emitted from motor vehicles, gasoline vapors, dry cleaners, refiners, factories, trees, and consumer and commercial products.

Nitrogen oxide, another ozone precursor, is emitted from motor vehicles, power plants, and other sources of combustion. Because ozone comes from so many different sources and it takes time for the reaction to occur, the reacting compounds can spread over a large area, creating a regional problem.

Depending on the meteorological conditions, winds can carry ozone, and the pollutants that form it, hundreds of miles away from the original sources. Peak ozone levels typically occur during hot, dry, stagnant summertime conditions. In Colorado Springs and in other communities along the Front Range, the typical ozone season is from June to September, and the highest levels are typically in June and July, although high concentrations can also occur outside of these months.

What are current ozone concentrations, and where can I find more information about ozone?
Go to the website of the Colorado Department of Public Health and Environment–Air Pollution Control Division.

• Realtime data is available for one-hour and eight-hour concentrations along with the corresponding Air Quality Index. Go to “Reports.”
• Ozone forecasts are conducted during the ozone season {from June 1 through August 31), and all ozone forecasts are issued by 4:00 p.m. the day before. Go to “Advisory.”
• This infomratin can also be accessed by clicking on the icon below to get the most current updates regarding ozone.

What are the human and environmental health effects of ozone?
Short-term (1-3 hours) and prolonged (6-8 hours) exposure to ambient ozone has been linked to a number of harmful health effects. Exposure to ozone can make people more susceptible to respiratory infection, result in lung inflammation, and aggravate pre-existing respiratory diseases such as asthma. Other health effects include a decrease in lung function and increased respiratory conditions such as chest pain and cough. These effects usually occur when individuals are actively exercising, working, or playing outdoors. Ozone can aggravate existing health problems for people with heart disease and breathing-related diseases such as asthma and emphysema. It can be especially hard on young children and elderly.

Ground-level ozone:

• interferes with the ability of plants to produce and store food, so that growth, reproduction, and overall plant health are compromised;
• has been shown to reduce agricultural yields for many economically important crops;
• is believed to add up over many years in long-lived species such as trees, so that whole forests or ecosystems can be affected;
• can kill or damage leaves so they fall off the plants too soon or become spotted or brown. These effects can significantly decrease the natural beauty of an area.

To learn more, visit the Air Quality Curriculum Project.

What is the ozone standard?
The 8-hour (primary and secondary) ozone standard is 0.075 0.080 parts per million (ppm) and is calculated by taking a consecutive three-year average of the fourth highest daily maximum for that year (usually this occurs during the ozone season). For ozone, the individual fourth max values for each year are not compared directly to the standard to determine a violation but averaged over a three-year period to determine a violation. Colorado Springs is currently in compliance with this new standard. These health standards were set by the US Environmental Protection Agency to protect public health and welfare and have been adopted by the State of Colorado. The Pikes Peak region remains in compliance with the primary and secondary standard set for ground-level ozone by the EPA on March 12, 2008, of 0.075 ppm.

Where is ozone monitored in the Colorado Springs region?
Ozone concentrations in the Colorado Springs area are measured at the US Air Force Academy (since 1996) and Manitou Springs (since April 2004) Monitoring Stations. Monitoring locations correspond to modeling which shows that the two ozone precursor pathways—corridors where concentrations of nitrogen oxide and hydrocarbons tend to be the highest—are up the Monument and Fountain Creek drainage basins.

What are the ozone trends in the Colorado Springs area?
The figure below shows the three-year average of the fourth max ozone concentrations since 1998. The current federal and state 8-hour ozone standard of .075 ppm is shown as the thick solid line across the graph that starts at 2008. Because ozone concentrations have only been measured in Manitou Springs since 2004, there are only six monitoring points (2006 through 2010) shown on this graph. The three-year average, based on 2008 through 2010 data, for the Air Force Academy is 0.066 ppm and 0.070 ppm for Manitou Springs, which shows that the Pikes Peak region is in attainment for the current standard.

2010 Ozone Season: Five Highest Ozone Concentrations
and Corresponding Data

Note: All concentrations are in ppm.

The high concentration measured on April 13, 2010, at both the Manitou Springs and USFA monitoring stations was potentially caused by an exceptional event (i.e., a stratospheric ozone intrusion). If the first max is excluded from the calculation, then the revised three-year average for 2008 through 2010 for the Manitou Springs monitoring station would be 0.069 ppm.

Three-year Average of 4th Max 8-hour Ozone Concentrations

Ozones Trends Using Three-Year Average of 4th Max Readings

What is the status of the proposed revisions to the National Ambient Air Quality Standards for Ozone?
The EPA intends to set a final primary and secondary standard for ozone by the end of July 2011. The primary standard is designed to protect public health, including at-risk populations such as children, people with asthma, and older adults; the secondary standard is designed to protect sensitive vegetation and ecosystems, including forests, parks, wildlife refuges, and wilderness areas. For the primary standard, EPA is proposing to adopt a more stringent 8-hour standard of between 0.060 to 0.070 parts per million (ppm) and a separate cumulative secondary standard within the range of 7–15 ppm-hours. The existing 8-hour standard, set in 2008, is 0.075 ppm; both the primary and secondary standard are set at the same value. PPACG is currently in attainment for the 0.075 ppm standard.

Ability of Region to Demonstrate Attainment with
Proposed Primary and Secondary Standard
A determination is made that an area will attain the standard if the value is equal to or below the standard and an area will violate the standard (causing it to be classified as in non-attainment) if concentrations are above it. If the current EPA proposal is approved, then concentrations would be rounded to the nearest part per billion. So if EPA goes forward as proposed, 0.0705 would violate a standard of 0.070, while 0.0704 would attain that standard. For the secondary standard, EPA proposes that, "The computed 3-year average of the annual maximum consecutive 3-month sum of adjusted monthly W126 index values in ppm-hours shall be rounded to a whole number with decimal values equal to or greater than 0.500 rounding up." So 15.4 ppm-hours would attain a standard of 15 ppm-hours, while 15.5 ppm-hours would violate, if this approach is unchanged in the final rule.