Continuous monitors have limitations

Letter to the editor from Parker Donham
Cape Breton Post
Sat., July 10, 2004

Bruno Marcocchio suggests we use a continuous air monitor to measure air quality near the tar ponds and coke ovens, and stream the results to the Internet (Weekend Feedback: Bring in Real Time Monitors, July 3). Doing so would be great public relations because a continuous monitor would demonstrate conclusively that air quality in Sydney is quite good - better than in Halifax, and much better than in most Canadian cities.

Unfortunately, a continuous monitor can measure only a single chemical. We measure more than 80 chemicals at each of six locations. Our monitoring stations can detect amounts as small as one part per trillion - at least 1,000 times more precision than continuous monitors are capable of.

That's why the air quality experts who designed our system, one of the most comprehensive in Canada, chose to rely on lab analysis of 24-hour air samples, supplemented by real-time checks with hand-held instruments.

Parker Donham
Sydney Tar Ponds Agency