I have heard about a controversy over Greenpeace’s latest assertions concerning the harm pollution is doing.

Before looking at the statistics and the specific claims, let’s put this in context.

The quality of the air we breathe is important.  It is affected by many things including exhaust from vehicles and certain industrial activity.   Poor quality air affects our health, especially respiratory problems.  Poor health can shorten your life.

Air quality can be improved by measures governments can take.  These measures usually have a cost to someone if not to all of us.  For example, banning motor vehicles would:

  • reduce pollution
  •  damage the economy
  • restrict our ability to travel.
  • That is without thinking about the effects on specific groups such as motor manufacturers and their employees.

As in most things, government involves choices and compromise.  Like Risk Management, it is a balancing act.

Now for the statistics.

Greenpeace claim that pollution in the UK causes 40,000 deaths a year.  What this should say is that it is possible that pollution is a factor in that number of deaths.

  • The figure is reached by an extrapolation from figures produced in the USA comparing death rates in different cities.
  • I understand that it compared all deaths regardless of cause.  So cities with high levels of pollution might have higher death rates due to crime, accidents, poverty or whatever.

Secondly, Greenpeace alleges that if you live in London, the air pollution is as harmful as smoking 15 cigarettes a day and takes 10 years off your life.  This is just plain wrong.  Smoking is definitely harmful and to a seriously high degree.  Literally hundreds of times worse than pollution.    To reduce pollution enough to make a difference to your lifespan of anything like one year, they would have to ban all motor vehicles from London.  Be serious!

Thirdly, what Greenpeace  do not say is that air quality in London has improved a lot in the late 20th Century and has leveled off in the last decade.  Room for improvement but also something to celebrate.

There are two sad things about these exaggerated claims:

  1.  There is a risk that the genuine concerns Greenpeace are trying to bring to our attention could be lost in the confusion.  The fact is that pollution is harmful and we should be looking for realistic, affordable measures to reduce it.
  2. Such a cavalier approach to statistics brings the whole of statistics into disrepute.  But we need to measure and compare things to make sensible decisions. See my book How to avoid being misled by statistics  https://www.createspace.com/4767398 or Kindle ASIN B00LPG8VUE

Be honest and scientific when you use statistics.  A good case does not need exaggerating.