Outdoor Air Quality Index (AQI) - Fine Particulate Matter 2.5 microns (PM 2.5)
- Analysis of Performance
- Metric Definition
- Why Is This Important?
- City Organization Impact on Performance
- Benchmark Information
Analysis of Performance
Fine Particulate Matter (PM2.5) concentrations did not meet the target in this quarter due primarily to atmospheric conditions such as wintertime inversions and transport from the Denver metro area.
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 fine particulate matter 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. A fine particulate matter target of 95% 'Good' days in a quarter was selected to evaluate local air quality conditions.
Why Is This Important?
Fine particulate matter can be breathed deeply into lungs and cause or worsen breathing problems, can cause premature death and can cause cardiovascular effects such as heart attack and stroke. PM 2.5 can also contribute to poor visibility (haze). In December 2012, the EPA tightened the federal health standard for fine particulate matter to better protect health.
City Organization Impact on Performance
Low - This metric is influenced much more directly by emissions from industry and impacts from events such as forest fires than it is by City efforts to implement emission reduction strategies and programs.
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.