At each moment in any geographic location, the air you inhale could be filled with pollutants. Everything from carbon monoxide to asbestos to particulate matter is inhaled and absorbed into our bodies. Needed rainfall might contain toxic deposits of nitric and sulfuric acids. Spring breezes wafting through our opened windows may be filling our lungs with CO2 emissions.
Elderly people or those who suffer from chronic respiratory ailments are more susceptible than others to airborne pollutants. For individuals whose physical bodies are more sensitive to pollution, it is essential that they receive up-to-date information about the air they breathe. And everyone needs to be aware when the air quality is at a dangerous level. How can you know if it is safe to walk outside on any given day?
Air Quality Index (AQI) Tracks Outdoor Pollutants
Three U.S. government agencies have combined forces to track and index air quality or what is known as the AQI (Air Quality Index). Together, these agencies have developed a website called AIRNow, where they report their collective findings on a daily basis.
This website brings forth data collected by the Environmental Protection Agency (EPA), which was legislated to monitor pollution, along with the National Oceanic and Atmospheric Administration (NOAA) and the National Park Service (NPS). State, local and tribal agencies also contribute to the site.
Guided by standards set by the EPA, AIRNow is an easy-to-decipher web zone with a mission of keeping the public aware of the nation’s air quality. Information is collected for 300 large cities across the United States, reporting on the danger or safety level of five major pollutants. The pollutants are all governed by the Clean Air Act, enacted 40 years ago. They include ground-level ozone, particle pollution, carbon monoxide, sulfur dioxide and nitrogen dioxide.
There is a vast amount of information and relevant links at the AIRNow website. But for the purpose of reporting the air quality level, it is divided into two major areas: Air Quality Forecasts and Air Quality Conditions.
Visitors to the site will find it can be searched very quickly by zip code or state. There is a separate entry page to view Air Quality Forecasts and Conditions by individual state and then cities within that state. Click on your state to bring up results, and then select your city or a nearby metropolitan area. This view shows a two-day forecast, if available, and the current AQI for each city.
Interpreting Air Quality Legends
The AIRNow site simplifies the interpretation of air quality conditions with a color-coded legend. There are six possible ranges of outdoor pollution, and each is tied to a numerical value of the AQI and possible health effects. The following definitions are from the AIRNow website.
- Good – (0-50) “Code Green.” Air quality is considered satisfactory, and air pollution poses little or no risk.
- Moderate – (51-100) “Code Yellow.” Air quality is acceptable; however, for some pollutants, there may be a moderate health concern for a very small number of people who are unusually sensitive to air pollution.
- Unhealthy for sensitive groups – (101-150) “Code Orange.” Members of sensitive groups may experience health effects. The general public is not likely to be affected.
- Unhealthy – (151-200) “Code Red.” Everyone may begin to experience health effects; members of sensitive groups may experience more serious health effects.
- Very Unhealthy – (201-300) Health alert: everyone may experience more serious health effects.
- Hazardous – (301-500) Health warnings of emergency conditions. The entire population is more likely to be affected. (Air quality index)
When the AQI falls into the Unhealthy range (Code Orange or Red), an “Action Day” is called by air pollution agencies, warning the public of the hazard. Under these circumstances, the public is advised to reduce their exposure to the pollutants by staying indoors. People with heart or lung disease, the elderly and children are more sensitive to air pollution levels than the rest of the population and are strongly advised to heed these warnings.
In the last thirty years, the level of common pollutants in the air has improved, according to the EPA. The same holds true for emissions – those pollutants released into the air by vehicles, factories and the like. One of the more common of these is carbon monoxide (CO), which has sharply decreased in three decades. In 1980, there was 178 million tons of CO tracked in the nation’s air. In 2015, that level dropped to 78 million tons. In the last ten years, the CO concentration level has decreased seventy percent.
Nevertheless, fires, older cars, and manufacturing plants still pollute the air, especially in larger cities with high populations. So if in doubt, always check the AIRNow site before heading out for the day.