What is PM 2.5?

PM 2.5 is particulate matter, fine inhalable particles with diameters that are generally 2.5 micrometers and smaller. How small is 2.5 micrometers? Think about a single hair from your head. The average human hair is about 70 micrometers in diameter – making it 30 times larger than the largest fine particle.

These particles come in many sizes and shapes and can be made up of hundreds of different chemicals. Some are emitted directly from a source, such as construction sites, unpaved roads, fields, smokestacks or fires. Most particles form in the atmosphere as a result of complex reactions of chemicals such as sulfur dioxide and nitrogen oxides, which are pollutants emitted from power plants, industries and automobiles. Source: EPA

What is ozone?

Ozone is a gas composed of three atoms of oxygen. Ozone occurs both in the Earth’s upper atmosphere and at ground level. Ozone can be good or bad, depending on where it is found. Good ozone occurs naturally in the upper atmosphere, where it forms a protective layer that shields us from the sun’s harmful ultraviolet rays. Ozone at ground level is a harmful air pollutant, because of its effects on people and the environment, and it is the main ingredient in “smog.” Ground level ozone is created by chemical reactions. This happens when pollutants emitted by cars, power plants, industrial boilers, refineries, chemical plants, and other sources chemically react in the presence of sunlight. Source: EPA


Click on the icons below to view current air quality conditions measured in the Salt Lake Valley by the Utah Division of Air Quality as well as PM 2.5 conditions from the Purple Air network (a citizen science community network of PM 2.5 sensors) for locations within and surrounding the Central Wasatch Mountains.

Purple Air
Purple Air
Utah Division of Air Quality
Utah Division of Air Quality

Explore historical air quality trends by selecting up to 5 years below.