"The Data sources used for the Air Quality, Air Pollution, PM2.5 (fine particulate matter), PM10 (respirable particulate matter), NO2 (nitrogen dioxide), SO2 (sulfur dioxide), CO (carbon monoxide), O3 (ozone)"
http://aqicn.org/?city=USA/Washington/Vancouver/NEVancouverThe problem with Air Quality Indices is that there is no international standard for the measurement of such Indices. As Wikipedia points out: "Different countries have their own air quality indices which are not all consistent. Different countries also use different names for their indices such as Air Quality Health Index, Air Pollution Index and Pollutant Standards Index."
http://en.wikipedia.org/wiki/Air_quality_indexTherefore it is not comparable what kind of air quality is in a specific region. The only reference made: "As the AQI increases, an increasingly large percentage of the population is likely to experience increasingly severe adverse health effects. "
http://en.wikipedia.org/wiki/Air_quality_indexDifferent populations of different countries can be in different shape because of nutrition, economic background, life style, history etc.
If the different governments relate to the U.S. System for example it measures only certain kind of data which might used to be important in the past but are not adapted to the structure of reality in the present or even the future. In fact, this kind of data system - as shown above - does not care for technological changes which produce new kinds of exhausts never known before. For example particles of the same material on nanoscale might behave differently than on a microscale. Coal dust might cause lower health damage than dust of new materials in nanoform. This is not measured because the consciousness about such contexts depends on what is shown to the population by the mass media.
At least, there is an air quality index what is better than nothing. But everyone ought to take caution to believe when there is written the term "good" which qualifies only the situation with the data measured. The term "good" does not describe the quality of air for materials not measured for.
This kind of look to the existing situation has the experience with the discoverage of health damage effects of asbestos in mind which used to be called "harmless".
There are so many used chemicals not investigated for health effects - as is shown in the discussion with the establishment of a data base about existing chemicals in Helsinki by the EU - one may be sceptical of the term "good" or "very good". They are not measured for.
The post above shows at least that it is common knowledge between Greenpeace and the Geo-Engineering-scepticals that particle below 2.5 micrometers are that dangerous that an air protection mask is needed.
