A report submitted by Ottawa’s deputy city manager to the Ottawa Planning and Environment Committee in December 2004 offers a fine example of how junk science can lead to junk regulation.

The Air Quality and Climate Change Management Plan calls for reducing greenhouse gas emissions from corporations and the community by 20 per cent, an effort justified by repeating a claim of the Ontario Medical Association that air pollution kills 100 Ottawa residents each year and hospitalizes another 900.

First, the junk science: despite claims to the contrary, Ottawa’s air pollution problems have mostly been licked. Ambient concentrations of the most important air pollutants (lead, carbon monoxide, sulphur dioxide, particulate matter and oxides of nitrogen) have declined sharply in Ottawa since the 1970s.

In fact, by 2002, the only air- pollution health standard to be violated was for ozone, and that was only exceeded in 15 instances lasting an hour or less in the entire year. Even with these violations, the average annual concentration of ozone in 2002 (26 parts per billion) was far below the Canada-wide annual standard for ozone (65 parts per billion).

With actual concentrations so low, where do these estimates of air-pollution deaths come from? Air-pollution body counts are produced by what are, literally, coincidence studies that look for small statistical correlations between air pollution and the number of people dead or hospitalized on a given day. And the two major studies from which such correlations have been derived are of dubious value.

In one study by the American Cancer Society, inconsistencies throw the question of cause into doubt. For example, Cancer Society researchers found an association between particulate exposure and mortality for the general population, but no association between exposure to fine particles and death was observed for persons with more than a high-school education, for women, or for people between the ages of 60 and 69, all of whom, as far as we know, breathe like everyone else. Fine particle exposure was associated with increased mortality for people who said they were moderately active, but not for people who said they were either sedentary or very active.

The other study, the Harvard Six Cities Study, also showed no association between exposure to fine particulate pollution and mortality in people with more than a high-school education. But, most amazing, the Harvard study also found that greater exposure to fine particles was associated with a statistically insignificant decrease in mortality, specifically due to respiratory causes. The bottom line is, the evidence linking current low levels of air pollution with harm to human health is anything but compelling.

Another scientific problem with the report is that it confuses greenhouse gases with traditional pollutants. Greenhouse gases, which the report targets, are not hazardous air pollutants, and there’s no demonstrable health or environmental benefit to be gained by reducing them. The pollutants that threaten human health include ozone, carbon monoxide, fine particulate matter, lead and sulphur dioxide. The gases that some people claim are changing Earth’s climate, such as carbon dioxide, methane and nitrous oxide are not health hazards at ambient levels. Carbon dioxide is the stuff you exhale, and that plants take in as food. Methane is what insects and animals put out when they break down wood or vegetation.

Second, the junk regulation: as innumerable reports have shown, pursuing greenhouse gas reductions will simply waste public resources, leaving people less able to deal with real problems, such as disease control, long medical waiting lists, underperforming schools and so on. When a leading group of economists evaluated the benefits of reducing greenhouse gas emissions compared to other life-saving investments such as controlling AIDS and malaria, improving nutrition, and providing people with safe drinking water, greenhouse gas emissions came in dead last.

Canadians are very concerned about air pollution. But despite the clamour of alarmist groups, the evidence suggests that we’ve driven the risk of air pollution far below any of the remaining major risks of death from infectious disease, dietary-related illnesses, cancer, heart disease, accidents and so on. As for the climate, the best way to prepare people to cope with the ever-changing climate of our planet (whether natural or man-made) is to build an economically prosperous and resilient society with a strong and adaptable infrastructure that will let us deal with whatever climate nature offers us.