Community air pollution in Canada: a review and predictions for the 1980s

Our plain-English summary of Community air pollution in Canada: a review and predictions for the 1980s, by D.V. Bates (Canadian Medical Association Journal, 1979).

The study

• Author: D.V. Bates
• Journal: Canadian Medical Association Journal
• Published: 1979;120(10):1252-6
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Free full text

Abstract

The main trends in Canadian air pollution since the national program of surveillance began are reviewed in this paper. In common with the United States, significant improvements in sulfur dioxide and particulate pollution have been recorded in a number of cities after the institution of control measures. However, some areas with a concentration of certain industries still have considerable particulate pollution. Since emission of nitrogen dioxide is increasing in the United States, the consequent photochemical pollution in southern Ontario will probably continue to increase. Nitrogen dioxide concentrations in the air are elevated in some western Canadian cities, presumably because of the presence of plants that burn natural gas to generate electricity and increasing pollution from automobiles. There is increasing concern about community air pollution in cities with large metal-fabricating plants, and community exposure to asbestos fibres is likely to be an important concern in the 1980s.

In plain English

This article was a review by a University of British Columbia professor, based on a 1978 address to the Canadian Lung Association. It examined trends in commonly measured Canadian air pollutants, using national surveillance data from the Department of the Environment, and made predictions for the 1980s. Sulfur dioxide had fallen substantially in Montreal and Toronto. In 1976, Hamilton's three stations averaged 101, 91 and 100 micrograms per cubic metre of suspended particulates, against an acceptable value of 70; these were higher than the average for any other city. Nitrogen dioxide rose from 1974 to 1976 in Edmonton and Winnipeg. Citing other researchers' work rather than new data, the author wrote that it appears inhabitants of most modern industrial cities acquire up to 20 000 asbestos fibres per gram of lung tissue without occupational or family exposure. The author wrote that this level would not cause classic fibrotic asbestosis but was very close to levels that appear to be associated with pleural mesothelioma. The author predicted that asbestos would remain an important community air pollution topic in the 1980s.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Narrative review, based on a conference address, of Canadian air pollution monitoring data, with predictions for the 1980s
• Who was studied: Air monitoring data from one representative downtown sampling station in each of several Canadian cities (including Montreal, Toronto, Hamilton, Sarnia, Vancouver, Calgary, Edmonton, Winnipeg and Halifax), mainly from 1971 to 1976, taken from national air pollution surveillance reports
• Exposure: Community air pollutants: sulfur dioxide, suspended particulates, nitrogen dioxide and ozone, plus a discussion of arsenic and of community (non-occupational) exposure to asbestos fibres, largely drawn from cited studies
• Main results:
  • Sulfur dioxide: substantial progress was made in Montreal and Toronto toward the Canadian maximum acceptable annual average of 2 pphm. Sarnia changed less, and Hamilton trended upward from 1972 but remained acceptable.
  • Suspended particulates: in 1976 the averages for Hamilton's three reporting stations (101, 91 and 100 micrograms per cubic metre) were higher than the average for any other city. The Canadian maximum acceptable value was 70 micrograms per cubic metre. Individual stations in Montreal, Sarnia, Calgary and Toronto also reported means above the acceptable value.
  • Nitrogen dioxide: concentrations increased from 1974 to 1976 in Edmonton and Winnipeg, and possibly in Hamilton, Sarnia and Montreal.
  • Ozone: one-hour 90th percentile values at the city sampling stations were generally below the Canadian maximum acceptable concentration of 8 pphm, though occasional values exceeded it.
  • Asbestos (a hedged statement citing another study, not this article's own data): the author wrote that it appears inhabitants of most modern industrial cities acquire up to 20 000 asbestos fibres per gram of lung tissue without occupational exposure or contact with an exposed family member.
  • Asbestos (the author's view, supported by citations): much of this asbestos probably comes from brake linings. This level would not lead to classic fibrotic asbestosis but is very close to levels that appear to be associated with pleural mesothelioma.
• The authors' conclusion: The author predicted rising concern about nitrogen dioxide and ozone in some Canadian cities. The author also predicted that asbestos would remain an important topic in community air pollution in the next decade, and concluded that chest physicians should keep their attention on these problems.
• Limitations the authors state:
  • It is difficult to generalize about large cities from a single sampling station.
  • Canadian nitrogen dioxide records only went back to 1974.
  • Ozone changes must be interpreted cautiously because they depend on environmental and weather conditions.
  • Downtown sampling sites do not represent areas downwind of major pollution sources.

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