See also:
Crafts
Ikebana
Botanical Gardens
The Air Quality Index (AQI) is a standardized indicator of the air quality in a given location. It measures mainly ground-level ozone and particulates (except the pollen count), but may also include sulphur dioxide, and nitrogen dioxide. Various agencies around the world measure such indices, though definitions may change between places.
The United States Environmental Protection Agency (EPA) and the Meteorological Service of Canada (MSC) differ on what AQI structure and health classification is used:
Health classifications used by the EPA:
0-50 Good is usually green
51-100 Moderate is usually yellow
101-150 Unhealthy for sensitive groups is usually orange
151-200 Unhealthy is usually red
201-300 Very unhealthy is usually purple
301-500 Hazardous is usually maroon
(AQI 100 corresponds to 0.08 ppm ozone; other levels for other pollutants) EPA
Health classifications used by the MSC:
0-25*: Good (green)
26*-50: Moderate (yellow)
51-100: Poor (orange/red)
101+: Very poor (purple)
In Ontario, 31 is the upper limit for good and 32 the lower limit for moderate.
The AQI can worsen (go up) due to lack of dilution with fresh air. Stagnant air, often caused by an anticyclone or temperature inversion, or other lack of winds lets air pollution remain in a local area. On these days, the news media may ask the public to carpool or use public transport, or take other air pollution prevention measures such as teleworking.
[more..]
|
