What is the Air Quality Index?

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Smoke from wildfires successful Canada has drifted into the U.S., prompting air quality alerts for Americans arsenic it continues to spread.

But erstwhile officials and forecasters classify a city's aerial arsenic "unhealthy" oregon "hazardous," what does that truly mean? The classifications are based connected a national measurement strategy called the Air Quality Index.

What is the Air Quality Index?

The Air Quality Index is utilized nationwide to measurement the severity of aerial contamination and categorize the wellness risks that are progressive with assorted levels of pollution. The scale uses six color-coded categories: bully (green), mean (yellow), unhealthy for delicate groups (orange), unhealthy (red), precise unhealthy (purple) and hazardous (maroon).

The wellness impacts included successful the scale are those that radical are apt to acquisition wrong "a fewer hours oregon days" aft being exposed to the air, the National Weather Service Says.

How is aerial prime measured?

The National Weather Service says that the Environmental Protection Agency calculates the Air Quality Index — a worth betwixt 0 and 500 — based connected 5 "major pollutants."

Those pollutants — ground-level ozone, particulate matter, c monoxide, sulfur dioxide and nitrogen dioxide — are each regulated by the Clean Air Act. Of those, ground-level ozone and airborne particles are considered "the top menace to quality health."

What bash the numbers mean?

Each Air Quality Index category, besides known arsenic the level of concern, is attached to a definite scope of values:

Good (green): 0 to 50
Moderate (yellow): 51 to 100
Unhealthy for delicate groups (orange): 101 to 150
Unhealthy (red): 151 to 200
Very unhealthy (purple): 201 to 300
Hazardous (marron): 301 and higher

Essentially, the little the number, the cleaner the air. The lone class wherever aerial prime is considered "satisfactory" is the 1 wherever the scale worth is nary much than 50, though values betwixt 51 and 100 are inactive considered "acceptable." After that, the aerial could airs a hazard to astatine slightest immoderate people, and that hazard lone becomes greater arsenic the scale worth rises.

Once the aerial is deemed "very unhealthy," the wide nationalist is astatine hazard of experiencing health impacts, which scope from a headache and fatigue to overmuch much superior issues specified arsenic bosom onslaught oregon stroke. At "hazardous" levels, the portion is experiencing an aerial prime emergency. Those with chronic respiratory oregon cardiovascular conditions are much astatine hazard of processing superior wellness issues arsenic contamination worsens.

What is the aerial prime adjacent me?

Air Quality Index values alteration perpetually passim the time arsenic upwind conditions and upwind patterns determination done the area. The representation beneath automatically updates to amusement aerial prime conditions nationwide.

The EPA's AirNow.gov tract uses the scale to supply the latest presumption for your area. To usage the site, participate your ZIP codification and a metre volition popular up showing you what the worth and colour class is for your city, arsenic good arsenic the past clip that measurement was updated.

It besides tells you what pollutant is causing issues, who is astir astatine hazard for wellness complications and what activities whitethorn beryllium harmless to do.

In Minneapolis, for example, the speechmaking connected Tuesday morning, June 3, said the AQI for PM2.5, a benignant of particulate matter, is 203, meaning "very unhealthy," and that radical who person bosom oregon lung disease, those who are elderly, and children and teens should debar outdoor carnal activity. In these conditions, everyone other should debar "strenuous" and agelong outdoor activities.

Li Cohen

Li Cohen is simply a elder societal media shaper astatine CBS News. She antecedently wrote for amNewYork and The Seminole Tribune. She chiefly covers climate, biology and upwind news.

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