The health consequences of air pollution can be considerable, and millions of people live in areas where it can cause serious health problems. Globally, the World Health Organization estimates that 3.7 million people per year die from the effects of air pollution, both urban and rural (WHO, 2014). Approximately 80% of air pollution-related deaths were due to coronary artery disease, while 14% were due to chronic obstructive pulmonary disease (COPD) or acute lower respiratory tract infections. While the majority of these premature deaths occurred in low- and middle-income countries, air pollution remains a significant cause of sickness and death in the U.S, although air quality has generally improved substantially in recent decades.
Like much of the country, the primary air pollutants of concern in Utah are ozone and particulate matter (PM). These pollutants typically exhibit substantial seasonal variation, with ozone higher in the summer and PM higher during the winter. There are several key features that affect local air quality. The majority of the Utah's population inhabits a relatively small area along the Wasatch Front. This concentrates the effects of human activity, and most air quality issues in Utah occur in this region.
The Air Quality Index and Your Health | Top
The Air Quality Index (AQI) is a tool used by government agencies, including EPA, the Utah Department of Health, and the Utah Department of Environmental Quality, to communicate information about current and forecasted air quality conditions to the public. The purpose of the AQI is to help you understand what local air quality conditions mean for your health. The AQI converts air pollutant concentrations into a single, simple number that is easy to understand: the higher the AQI value, the greater the level of air pollution and the greater the health concern.
An AQI value of 100 roughly corresponds to the national air quality standard for the pollutant of concern. This is the level EPA has set to protect public health, and AQI values at or below 100 are generally thought of as satisfactory. When AQI values are above 100, air quality is considered to be unhealthy - at first for certain sensitive groups (e.g., children or people with heart or lung diseases), then for everyone as AQI values increase.
In Utah, the AQI is based on concentrations of the two primary air pollutants of concern, particulate matter and ozone. You can help protect your health from the effects of air pollution by monitoring air quality in your area using the AQI and modifying your activities as necessary. The adjustments that are needed when the AQI is high will vary from person to person, but may include reducing the amount of time spent outdoors or choosing less strenuous activities.
Winter Temperature Inversions and Particulate Matter | Top
Geography and prevailing weather conditions also play a significant role in the form of winter temperature inversions in the Wasatch Front and Uintah Basin. An inversion results when cold air is held close to the ground by a layer of warmer air above, trapping air pollutants and significantly lowering air quality. The mountains surrounding the major populated valleys in the Wasatch Front (e.g., Salt Lake, Utah, Cache, etc.) contribute to inversions by preventing air movement from dispersing the inversion.
Click on image to learn more about temperature inversions from the National Weather Service.
In Utah, particulate matter is the pollutant of primary concern during inversions. Lengthy inversions can result in exceedances of the EPA's National Ambient Air Quality Standards for particulate matter. Click here to learn more about standards, trends, and health effects associated with particulate matter.
Looking west down Mill Creek Canyon at an inversion in Salt Lake Valley, December 2013
Ozone in the Uintah Basin | Top
Winter temperature inversions also occur in the Uintah Basin; these are unusual due to the presence of elevated ozone levels rather than the particulate matter typically associated with inversions. During an inversion in the Uintah Basin, volatile organic compounds and oxides of nitrogen are concentrated close to the ground and react to form ozone. A number of studies investigating this phenomenon are ongoing; visit the Utah Department of Environmental Quality website for further information. To learn more about standards, trends, and health effects associated with ozone, visit this site's ozone page.
The Bonanza Power Plant near Vernal, UT. Image courtesy of UDEQ