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Outdoor Air Quality Index (AQI) - Ozone

Desired Result: Above Target

Analysis of Performance

Note: "Review and validation of this data is conducted by the CO Department of Public Health and Environment (CDPHE) and can take 8 - 12 weeks after the quarter ends. Accordingly, current performance is based on the prior quarter's results."

Ground level ozone concentrations exceeded the target for this quarter by one percent. Ozone formation is influenced by many factors including intensity and hours of sunlight, stability of the atmosphere, and sources of air pollutants. Higher ozone concentrations are typical in the summer months.

Metric Definition

The metric is a measure of the number of 'good' air quality days (as defined by EPA's Air Quality Index - AQI) in a quarter based on ozone air monitoring data from Fort Collins. The AQI is calculated by EPA as a measure of local air quality and its effect on human health. The higher the AQI value, the greater the level of air pollution and the greater the health concern. 'Good' air quality corresponds to an AQI of 50 or less (on a scale of 0-500) and poses little or no risk of adverse health effects. An ozone target of 75% 'Good' days in a quarter was selected to evaluate local air quality conditions.

Why Is This Important?

Ground level ozone is a respiratory irritant. Children, older adults, people with lung disease, and people who are active outdoors may be particularly sensitive to ozone. Fort Collins is part of the Front Range area that is out of compliance with the 8-hour ozone health standard.

City Organization Impact on Performance

Low - This metric is influenced much more directly by atmospheric conditions and emissions from motor vehicles and industry than it is by City efforts to implement emission reduction strategies and programs.

Benchmark Information

THE AQI for ozone and particulate matter have not been benchmarked against other world class cities because the measures are highly influenced by local and regional factors that are not comparable to other cities. Ozone concentrations are influenced by meteorological and topographical conditions that can be unique to each city. In addition, ozone is influenced by transport from other regions. Particulate matter concentrations are influenced by local climate conditions and local emission sources that can be unique to each city and can be highly influenced by natural events such as wildfire.