Air Pollution
What is air pollution?
Air pollution is a mix of hazardous substances from both man-made and natural sources. Vehicle emissions, fuel oils and natural gas to heat homes, by-products of manufacturing and power generation, particularly coal-fueled power plants, and fumes from chemical production are the primary sources of human-made air pollution.
Frequently Asked Questions
Like much of the country, the primary air pollutants of concern in Utah are ground-level ozone and particulate matter (PM). Levels of these pollutants can vary by season, with ozone higher in the summer and PM higher during the winter.
- Noxious gases
- Noxious gases, which include carbon dioxide, carbon monoxide, volatile organic compounds (VOCs), nitrogen oxides (NOx), and sulfur oxides (SOx), are components of motor vehicle emissions and byproducts of industrial processes.
- Ozone
- Ozone (O3) is an atmospheric gas, which is often called smog when at ground level. It is created when the pollutants NOx and VOCs emitted by cars, power plants, industrial boilers, refineries, and other sources chemically react in the presence of sunlight. It is one of the six EPA criteria pollutants.
- PM
- Particulate matter (also called PM or particle pollution) is a complex airborne mixture of solid particles and liquid droplets. It is composed of chemicals such as sulfates, nitrates, carbon, or mineral dusts. Vehicle and industrial emissions from fossil fuel combustion, cigarette smoke, and burning organic matter, such as wildfires, all contain PM.Though PM ranges widely in size, it has been divided into two categories based on diameter.
- PM2.5: Particles with a diameter smaller than 2.5 micrometers (µm, or microns)
- PM10: Particles with a diameter between 2.5 µm and 10 µm
- Particulate matter (also called PM or particle pollution) is a complex airborne mixture of solid particles and liquid droplets. It is composed of chemicals such as sulfates, nitrates, carbon, or mineral dusts. Vehicle and industrial emissions from fossil fuel combustion, cigarette smoke, and burning organic matter, such as wildfires, all contain PM.Though PM ranges widely in size, it has been divided into two categories based on diameter.
- Lead
- Lead is a toxic heavy metal that can be found in all parts of our environment, partly due to human activities. Major sources of lead in the air include ore and metals processing and piston-engine aircraft operating on leaded aviation fuel. Other sources are waste incinerators, utilities, and lead-acid battery manufacturers. The highest air concentrations of lead are usually found near lead smelters. Once released into the air it may travel long distances before it settles to the ground, where it usually binds strongly to soil particles.
Exposure to air pollution can affect everyone’s health. When we breathe, pollution enters our lungs and can enter our bloodstream. Air pollution can contribute to small annoyances such as coughing or itchy eyes. Exposure to both particulate matter and ozone can also cause or worsen many diseases involving the lungs and heart, leading to hospitalizations, cancer, or even premature death.
Daily AQI Color | Levels of Concern | Values of Index | Description of Air Quality |
---|---|---|---|
Green | Good | 0 to 50 | Air quality is satisfactory, and air pollution poses little or no risk. |
Yellow | Moderate | 51 to 100 | Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. |
Orange | Unhealthy for Sensitive Groups | 101 to 150 | Members of sensitive groups may experience health effects. The general public is less likely to be affected. |
Red | Unhealthy | 151 to 200 | Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. |
Purple | Very Unhealthy | 201 to 300 | Health alert: The risk of health effects is increased for everyone. |
Maroon | Hazardous | 301 and higher | Health warning of emergency conditions: everyone is more likely to be affected. |
Air Quality Index | Who Needs to be Concerned? | What Should I Do? |
---|---|---|
Good (0-50) |
It's a great day to be active outside. | |
Moderate (51-100) |
Some people who may be unusually sensitive to particle pollution. | Unusually sensitive people: Consider reducing prolonged or heavy exertion. Watch for symptoms such as coughing or shortness of breath. These are signs to take it easier. Everyone else: It’s a good day to be active outside. |
Unhealthy for Sensitive Groups (101-150) |
Sensitive groups include people with heart or lung disease, older adults, children and teenagers. | Sensitive groups: Reduce prolonged or heavy exertion. It’s OK to be active outside, but take more breaks and do less intense activities. Watch for symptoms such as coughing or shortness of breath. People with asthma should follow their asthma action plans and keep quick relief medicine handy. If you have heart disease: Symptoms such as palpitations, shortness of breath, or unusual fatigue may indicate a serious problem. If you have any of these, contact your heath care provider. |
Unhealthy (151-200) |
Everyone | Sensitive groups: Avoid all physical activity outdoors. Move activities indoors or reschedule to a time when air quality is better. Everyone else: Avoid prolonged or heavy exertion. Consider moving activities indoors or rescheduling to a time when air quality is better. |
Very Unhealthy (201-300) |
Everyone | Sensitive groups: Avoid all physical activity outdoors. Move activities indoors or reschedule to a time when air quality is better. Everyone else: Avoid prolonged or heavy exertion. Consider moving activities indoors or rescheduling to a time when air quality is better. |
Hazardous (301-500) |
Everyone | Everyone: Avoid all physical activity outdoors. Sensitive groups: Remain indoors and keep activity levels low. Follow tips for keeping particle levels low indoors. |
Air Quality Index | Who Needs to be Concerned? | What Should I Do? |
---|---|---|
Good (0-50) |
It's a great day to be active outside. | |
Moderate (51-100) |
Some people who may be unusually sensitive to ozone. | Unusually sensitive people: Consider reducing prolonged or heavy outdoor exertion. Watch for symptoms such as coughing or shortness of breath. These are signs to take it easier. Everyone else: It’s a good day to be active outside. |
Unhealthy for Sensitive Groups (101-150) |
Sensitive groups include people with lung disease such as asthma, older adults, children and teenagers, and people who are active outdoors. | Sensitive groups: Reduce prolonged or heavy outdoor exertion. Take more breaks, do less intense activities. Watch for symptoms such as coughing or shortness of breath. Schedule outdoor activities in the morning when ozone is lower. People with asthma should follow their asthma action plans and keep quick relief medicine handy. |
Unhealthy (151-200) |
Everyone | Sensitive groups: Avoid prolonged or heavy outdoor exertion. Schedule outdoor activities in the morning when ozone is lower. Consider moving activities indoors. People with asthma, keep quick-relief medicine handy. Everyone else: Reduce prolonged or heavy outdoor exertion. Take more breaks, do less intense activities. Schedule outdoor activities in the morning when ozone is lower. |
Very Unhealthy (201-300) |
Everyone | Sensitive groups: Avoid all physical activity outdoors. Move activities indoors or reschedule to a time when air quality is better. People with asthma, keep quick-relief medicine handy. Everyone else: Avoid prolonged or heavy outdoor exertion. Schedule outdoor activities in the morning when ozone is lower. Consider moving activities indoors. |
Hazardous (301-500) |
Everyone | Everyone: Avoid all physical activity outdoors. |
Note: If you don't have an air conditioner, staying inside with the windows closed may be dangerous in extremely hot weather. In these cases, seek alternative shelter.


Wildfire Smoke
Frequently Asked Questions
Smoke may worsen symptoms for people who have pre-existing health conditions and those who are particularly sensitive to air pollution. Sensitive groups include:
- People with asthma or other chronic respiratory disease
- People with respiratory infections
- People with cardiovascular disease
- People ≥ 65 years of age
- People with diabetes
- Infants and children
- Pregnant woman
- Smokers, especially those who have smoked for several years
High concentrations of smoke can cause a range of health problems, including:
- Burning eyes, a runny nose, cough, phlegm, wheezing, chest pain, and difficulty breathing.
- If you have heart or lung disease, smoke may make your symptoms worse.
- People with heart disease might experience chest pain, palpitations, shortness of breath, or fatigue.
- People with lung disease may not be able to breathe as deeply or as vigorously as usual, and may experience symptoms such as coughing, phlegm, chest discomfort, wheezing and shortness of breath.
Limit your exposure to the smoke:
- Stay indoors whenever possible and keep indoor air clean by closing doors and windows.
- Avoid physical activities outdoors if smoke is in the air.
- Avoid activities that create more indoor pollution, such as frying foods, sweeping, vacuuming, burning candles, smoking and using gas-powered appliances.
- Use a portable air cleaner with a high-efficiency (HEPA) air-cleaning filters.
- Choose quality air cleaning technologies that do not create ozone.
- How to Choose a Portable Air Cleaner - CEHN
- Use a do-it-yourself HEPA-filter box fan (Español).
- Drink plenty of water to help reduce symptoms of scratchy throat and coughing.
- Monitor the air quality conditions in your area at air.utah.gov
- Consider leaving the area if air quality is poor and it’s not possible to keep indoor air clean, especially for those who have health conditions.
- Check the local air quality index (AQI) on the Utah DEQ’s website or the AirNow website.
- Visit Utah Wildfires Information website.
Indoor Air Quality
Indoor Air Quality (IAQ) refers to the air quality within and around buildings and structures, especially as it relates to the health and comfort of building occupants. The average person spends up to 90 percent of their time inside. Poor indoor air quality can cause similar health effects as exposure to outdoor pollution such as: decreased lung size and function, acute respiratory illnesses (such as asthma and bronchitis), emphysema, and even some types of cancer.
Frequently Asked Questions
A person’s risk of experiencing health effects from air pollution varies depending on their age, where they live, underlying health conditions, and other factors. People most at risk of health problems related to indoor air pollution include:
- People with lung diseases, such as asthma, chronic bronchitis, emphysema, and chronic obstructive pulmonary disease(COPD)
- Infants and young children
- Adults older than 65
- People with a cardiovascular disease
- People who smoke or are exposed to second-hand smoke
- On poor air days, keep doors and windows shut to keep pollutants out.
- Open windows and doors to increase airflow, when outdoor air quality is good.
- Do not use scented or unscented candles, artificial air fresheners, or products with fragrances.
- Optimize heat, ventilation, and air conditioning (HVAC) systems.
- Use a portable air cleaner with a high-efficiency (HEPA) air-cleaning filters.
- Choose quality air cleaning technologies that do not create ozone.
- How to Choose a Portable Air Cleaner - CEHN
- A home-made HEPA-box fan filter (Español) is an excellent ventilation alternative.
- Avoid activities that create more indoor pollution, such as frying foods, sweeping, vacuuming, burning candles, smoking and using gas-powered appliances.