no2-gas-500x500It’s been a slightly chastening week for me this week as I being to discover that my understanding of what detracts from air quality, ie pollutants, is not as good as I thought it was.  So in an effort to improve this I’ve been doing some self teaching and listening to others.  If you are interested, do follow my journey over the next week or two.


Here’s a pretty balanced video from London.  It gives expert explanations in three minutes as to the effects of NO2, on people living and breathing invisible quantities for the short and long term.  In simple terms we recover from short term episodes which might involve breathing difficulties.  After decades of exposure then the condition becomes chronic, debilitating and life shortening.

I’ve already lapsed into scientific jargon with ‘NO2‘.  This is the chemical symbol for nitrogen dioxide, a brown gas, one of several oxides of nitrogen, and the one most associated with breathing difficulties, and whose presence is widely attributed to high temperature combustion of fossil fuels such as in vehicle engines.

Its concentration in the air is expressed as micrograms per cubic metre.  I’ve not researched the legislation carefully yet but the figure bandied around is 40ug/mwhere ‘u’ stands for ‘mu’, the greek letter, which denotes, ‘micro’, or a millionth of something.  To try to put some scale on this, a Camden living room has a volume of perhaps 25 cubic metres.  The legal limit would allow there to be one tenth of a milligram NOin the whole room which if solid would look like a grain of sugar.  We are talking about tiny, imperceptible amounts, not the smelly car fumes we often detect along Camden Road.  That’s another story.


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