PGAQ #72 by Vic Steblin, Dec 27, 2008

2570 Laurier Crescent, Prince George, BC, 250-564-1123

The Prince George air shed contains a definite amount of air which constantly receives particle pollution in various amounts. If a decent clearing wind blows the particles away then the entering pollution does not matter much and hardly anyone complains.

An air advisory is triggered when the fine particulate reaches 25ug per cubic metre. How long this takes depends on how much pollution is produced and the speed of the wind. With calm cold days and hundreds of industrial stacks and wood stoves it only takes a few days to reach the limit.

One kilogram of wood can add 1 ug to a billion cubic metres of air if all the mass gets to smoke particles. A billion cubic metres is a cubic kilometre. 25 kilograms of wood can fill that cubic kilometre to the air advisory limit of 25 ug. In reality the actual amount of smoke from 1 kg depends on the type of wood and the burner.

If one knows how many cubic kilometres our air shed contains and to what height the air can be polluted, then one can calculate how many kilograms of wood it takes to reach the particulate limit. An estimation of our air shed as 20km by 20km by 100 metres high means that there are 40 cubes of kilometre size. It should take 40 wood stoves burning 25 kilograms each to reach the advisory limit with no clearing wind.

Of course reality is complicated. One kilogram of wood produces different amounts of smoke depending on the conditions. The particles themselves are not evenly distributed and may sink down to various levels during an inversion. Also the water vapour and carbon dioxide components are relatively harmless to human health.

Over 40 significant polluting industries plus thousands of vehicles and wood stoves are in our air shed. We have a serious air quality problem and serious solutions are needed. Individuals can help by totally butting out. Industry also needs stricter standards and the use of the best electrostatic precipitators.