23 October 2006

What did you breath today?

I decided to do a little research on different Air Quality levels around the world today. The results I already knew, but just wanted some actual numbers and to know what they meant. Pretty much everyone calls it the Air Quality Index (AQI) but Hong Kong calls it the Air Pollution Index (API). The numbers used don't always mean the same and the UK is different as well. Anyway here are the numbers for today. The numbers for HK are at midnight! during the day they are even worse, but I don't want to scare anyone.

Hong Kong (at midnight)
Central - 57 (60+ during the day)
Causeway bay - 65 (70+ during the day)
Mong Kok - 73 (85+ during the day)

Canada (Morning)
Winnipeg - 9
Calgary - 8
Vancouver - 12
Toronto - 10
Montreal -10

New York City - 45
London - 3 (They use a system up to 10 only)

(From wikipedia >>>)

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.

United Kingdom

The Met Office of the United Kingdom (UK) issues air quality forecasts wherein the level of pollution is described either as an index (ranging from 1 to 10) or as a banding (low, moderate, high or very high). These levels are based on the health effects of each pollutant.

Hong Kong (Main article: Air Pollution Index)

The Air Pollution Index (API) levels for Hong Kong are related to the measured concentrations of ambient respirable suspended particulate (RSP), sulphur dioxide (SO2), carbon monoxide (CO), ozone (O3) and nitrogen dioxide (NO2) over a 24-hour period based on the potential health effects of air pollutants.

An API level at or below 100 means that the pollutant levels are in the satisfactory range over 24 hour period and pose no acute or immediate health effects. However, air pollution consistently at "High" levels (API of 51 to 100) in a year may mean that the annual Hong Kong "Air Quality Objectives" for protecting long-term health effects could be violated. Therefore, chronic health effects may be observed if one is persistently exposed to an API of 51 to 100 for a long time.

"Very High" levels (API in excess of 100) means that levels of one or more pollutant(s) is/are in the unhealthy range. The Hong Kong Environmental Protection Department provides advice to the public regarding precautionary actions to take for such levels.


Ok, so based on this research, Hong Kong is just plain stupid. It's not even recommended for people to be outside for more than 24 hours. That's ok with me, cause it's too damned hot, but this is ridiculous. Anyone more interested can find more info at wiki.

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