Air pollution with text: "clean air month: air pollutants"

The Air Quality Index

Hearing a lot about clean air these days? Pollution. Climate change. Carbon footprints. It is a multi-faceted issue that can be a whole lot to take in. Why is it important? Because poor air quality can have a negative impact on the environment and lead to long-term health problems.

The air quality index, or AQI, helps us to quantify the quality of the air and how clean or polluted it may be. Using the AQI, it’s possible to alter plans or take extra precautions to ensure the air you breathe is safe.

What is the Air Quality Index?

The air quality index is a scale used to rate and report on the quality of the air outdoors in an area or region. Air quality is often used to determine whether normal outdoor activities can take place without special considerations or accommodations.

Just like the weather, air quality may fluctuate over the course of the day, week, month or year. Further, it can be predicted – to an extent.

Why Is the Air Quality Index Important?

The air quality index is designed to help keep people safe. When air quality is poor, you pay the price – dry eyes, headaches, nasal congestion, nausea, fatigue, asthma, lung diseases, infections, cancer, and more. The air quality index helps by flagging days or times when outdoor activities should be modified or canceled.

How Does the Air Quality Index Work?

The air quality index is a measure from 0-500. The lower the number, the cleaner the air. In general, numbers between 0-100 are viewed as satisfactory. The AQI is divided into six categories that are color-coded based on the quality of the air at hand.

Each of the major pollutants regulated by the Clean Air Act (ground-level ozone, carbon monoxide, sulfur dioxide, particulate pollution and nitrogen dioxide) have an established AQI.

It’s important to note that air quality is determined not only by pollutants present, but the rates at which they are released and dissipate.

Understanding the Air Quality Index Colors

The Air Quality Index reports daily air quality – how clean or polluted the air in your area is – with the help of a color-coded scale:

  • Green: 0-50 – GOOD

Little or no health risk

  • Yellow: 51-100 – MODERATE

Acceptable, though some extremely sensitive individuals may experience respiratory issues


People with heart and lung disease, children, and older adults are at a greater risk from ozone and particulates

  • Red: 151-200 – UNHEALTHY

Everyone may experience adverse effects, with sensitive individuals suffering more serious issues

  • Purple: 201-300 – VERY UNHEALTHY

Serious health effects from exposure, typically accompanied by widespread health alerts

  • Maroon: 301-500 – HAZARDOUS

Widespread health warnings and emergency conditions that will affect the entire population

Outdoor Pollutants

There are several types of pollutants that can cause poor outdoor air quality. Here is a list of the most common pollutants you may encounter:

  • Ozone (O3)

A highly reactive form of oxygen typically resulting from fuel combustion. Exposure sears the lungs.

  • Carbon monoxide (CO)

Carbon monoxide is a colorless, odorless byproduct of gas-fueled vehicles.

  • Nitrogen oxide (NOx)

Emitted from vehicles, particularly during rush hour “standing,” as well as from power stations. In combination with precipitation, results in acid rain.

  • Hydrocarbons

Released when fuels such as gas and diesel are not fully burned, resulting in smog.

  • Sulfur dioxide (SO2)

Most often released by power stations and industrial facilities burning coal and oil. Can also result in acid rain.

  • Particulate matter (PM)

Small particles of soot, dust, and fumes released into the air from vehicles, factories, coal-burning heat sources, and more.

Indoor Pollutants

While not measured by AQI, indoor pollutants can be just as, if not more detrimental to your health. Indoor air pollutants are typically more concentrated due to the lack of ventilation and being confined inside a structure. Some of the common indoor pollutants may not really be that dangerous if they were outside. It is important to be aware of the indoor pollutants you may encounter.

  • Cigarette smoke

Contains thousands of chemicals.

  • Mold

Toxic spores from the proliferation of mold due to excess humidity in your home.

  • VOCs

Carbon-based chemicals that evaporate or off-gas at room temperature. Released from thousands of products, from paints, cleaning supplies, and building materials to glues, fuels, furniture, carpeting, office equipment, and more.

  • Carbon monoxide (CO)

From improperly vented fireplaces and combustion appliances.

  • Radon

Colorless, odorless, radioactive gas from the natural breakdown of uranium in the earth.

  • Allergens

Dust mites, pet dander, pollen, and other triggers.

How to Keep Indoor Air Clean

While controlling the quality of the air outside is difficult, you can control the quality of the air in your home! Keep indoor air pollutants at bay in your home by:

  • Never allowing cigarette smoke inside your home.
  • Adding air purifiers.
  • Maintaining proper humidity levels.
  • Reducing the use of pesticides and synthetic cleaners.
  • Choosing natural furnishings.
  • Ensuring your home is properly ventilated.
  • Operating appliances (dishwashers, washers, dryers) only when full.
  • Opting for energy-efficient appliances and electronics.
  • Reducing, reusing and recycling materials.

Minimize Your Carbon Footprint

While you can’t control the outdoor air quality, you can reduce your impact by:

  • Consolidating errands into as few trips as possible.
  • Walking, biking, carpooling or using public transportation.
  • Driving with a light foot and avoid engine revving.
  • Insulating and weatherizing your home to reduce fossil fuel consumption via heating and cooling.
  • Keeping home windows closed when operating your heating or air conditioning system.
  • Adjusting the temperature when you are away from home to conserve energy or upgrading to a programmable thermostat.
  • Having your heating and cooling system professionally serviced annually to improve efficiency.

Find Residential Indoor Air Quality Testing Near Me

Reducing your exposure to air pollutants indoors with help from your local Aire Serv. Choose Aire Serv for all your indoor air quality testing needs. Request an appointment online or call (855) 679-0011 to get started.