Advertisement

Canadian Journal of Public Health

, Volume 98, Issue 5, pp 364–368 | Cite as

Anatomy of Heat Waves and Mortality in Toronto

Lessons for Public Health Protection
  • L. David Pengelly
  • Monica E. CampbellEmail author
  • Chad S. Cheng
  • Chao Fu
  • Sarah E. Gingrich
  • Ronald Macfarlane
Article
  • 1 Downloads

Abstract

Background

Periods of unusually hot weather, especially in temperate climates, carry with them a burden of morbidity and mortality, particularly in urban areas. With lessening debate on its origins, and signs of global warming already apparent, it is becoming imperative for public health practitioners to recognize and predict the risks of “heat waves”, and to develop protective community responses to them. This study makes use of historical data and a methodology developed previously to examine the pattern of hot weather experienced over the last five decades in the City of Toronto, and to assess the associated burden of mortality.

Methods

Synoptic classification of air masses based on meteorological data for Toronto was used, to assign the annual mean burden of illness (in terms of elevated mortality) associated with hot weather and air pollution. Then, coefficients relating daily mortality risk to historical daily weather and air quality data were determined with a model system that (for each air mass) assessed the factors that contributed to day-to-day variability in mortality.

Results

Over the period of study, there were 120 (95% CI: 105-135) heat-related deaths on average per year, with great variability from year to year, reflecting the variability of hot weather. Mortality was greatest in July and August, when the greatest number of multi-day heat episodes occurred. Furthermore, the longer the episode, the greater was the daily risk for mortality.

Interpretation

The method can be used to forecast the risk of heat-related mortality, and to facilitate the development of public health responses to mitigate that risk.

MeSH terms

Heat mortality environment public health climate 

Résumé

Contexte

Les périodes de canicule, surtout sous les climats tempérés, font peser un fardeau de morbidité et de mortalité sur la population, particulièrement en zone urbaine. Maintenant que la polémique sur les origines du réchauffement planétaire, dont les signes sont déjà apparents, commence à s’estomper, les praticiens de la santé publique doivent impérativement savoir reconnaître et prédire les risques de « vagues de chaleur » et les combattre par des mesures de protection de la population. Sur la base de données historiques et d’une méthode élaborée antérieurement, nous avons examiné les périodes de temps chaud observées au cours des 50 dernières années à Toronto et évalué le fardeau de mortalité connexe.

Méthode

Grâce à la classification synoptique des masses d’air d’après les données météorologiques pour Toronto, nous avons estimé la proportion du fardeau annuel moyen des maladies (la mortalité accrue) associée au temps chaud et à la pollution atmosphérique. Nous avons ensuite établi des coefficients reliant le risque quotidien de mortalité aux températures quotidiennes historiques et aux données sur la qualité de l’air à l’aide d’un modèle qui (pour chaque masse d’air) évaluait les facteurs ayant contribué aux variations quotidiennes de la mortalité.

Résultats

Pendant la période à l’étude, 120 décès par année en moyenne étaient liés à la chaleur (IC de 95 % = 105–135), avec une grande variabilité d’une année à l’autre, laquelle reflétait la variabilité du temps chaud. La mortalité était au maximum en juillet et en août, période où l’on a observé le plus grand nombre d’épisodes de plusieurs jours de temps chaud. Plus les épisodes étaient longs, plus le risque quotidien de mortalité était élevé.

Interprétation

Cette méthode peut servir à prévoir le risque de mortalité liée à la chaleur et faciliter l’élaboration de mesures de santé publique pour atténuer ce risque.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    U.S. EPA Aging Initiative. Keeping Cool: Innovative Partnerships to Protect Older Adults from Extreme Heat. Available online at: https://doi.org/www.epa.gov/aging/press/profiles/ 2004_05_dallas.htm (Accessed February 8, 2006).Google Scholar
  2. 2.
    U.S. Department of Health and Human Services: Centers for Disease Control and Prevention. CDC Program in Brief. Extreme Heat. 2004. Available online at: https://doi.org/www.cdc.gov/programs/ environ10.htm (Accessed February 8, 2006).Google Scholar
  3. 3.
    Jones PD, Moberg A. Hemispheric and largescale surface air temperature variations: An extensive revision and an update to 2001. J Climate 2003;16:206–23.CrossRefGoogle Scholar
  4. 4.
    Hansen J, Ruedy R, Sato M, Lo K. Global Temperature Trends: 2005 Summation: NASA Goddard Institute for Space Studies and Columbia University Earth Institute, New York, NY. Available online at: https://doi.org/data.giss.nasa.gov/ gistemp/2005 (Accessed February 10, 2006).Google Scholar
  5. 5.
    Masterton JM, Richardson, FA. A Method of Quantifying Human Discomfort Due to Excessive Heat and Humidity. CLI 1-79: AES, Environment Canada, Downsview, Ontario, 1979.Google Scholar
  6. 6.
    Sheridan SC, Kalkstein, LS. Progress in heat watch–warning system technology. Bull Amer Meteorolog Soc 2004;85(12):1931–41.Google Scholar
  7. 7.
    Toronto Public Health. Influence of Weather and Air Pollution on Mortality in Toronto. Summary Report of Differential and Combined Impacts of Winter and Summer Weather and Air Pollution due to Global Warming on Human Mortality in South-Central Canada: Toronto Public Health, 2005. Available online at: https://doi.org/www.toronto.ca/health/hphe/pdf/weather_air_ pollution_summary_june_2005.pdf (Accessed August 22, 2007).Google Scholar
  8. 8.
    Cheng CS, Campbell M, Li Q, Li G, Auld H, Day N, et al. Differential and Combined Impacts of Winter and Summer Weather and Air Pollution due to Global Warming on Human Mortality in South-Central Canada. Technical Report: Health Canada, Environment Canada and Toronto Public Health, Toronto, 2005. Available online at: https://doi.org/www.toronto.ca/ health/hphe/weather_air_pollution_research.htm (Accessed August 22, 2007).Google Scholar
  9. 9.
    Cheng CS, Campbell M, Li Q, Li G, Auld H, Day N, et al. Differential and combined impacts of extreme temperatures and air pollution on human mortality in south-central Canada. Part I: historical analysis. Water, Air, & Soil Pollution 2007;182:131–48.CrossRefGoogle Scholar
  10. 10.
    Kalkstein LS, Jamason PF, Greene JS, Libby J, Robinson L. The Philadelphia hot weather-health watch/warning system: Development and application, summer 1995. Bull Amer Meteorolog Soc 1996;77:1519–28.CrossRefGoogle Scholar
  11. 11.
    Kalkstein LS, Barthel CD, Ye H, Smoyer K, Cheng S, Greene JS, et al. The impacts of weather and pollution on human mortality. Publications in Climatology 1997;L(1):58 pp.Google Scholar
  12. 12.
    Kalkstein LS, Davis, RE. Weather and human mortality: An evaluation of demographic and interregional responses in the United States. Ann Assoc Am Geographers 1989;79(1):44–64.CrossRefGoogle Scholar
  13. 13.
    Davis RE, Knappenberger PC, Novicoff WM, Michaels, PJ. Decadal changes in summer mortality in U. S. cities. Int J Biometeorol 2003;47:166–75.PubMedGoogle Scholar

Copyright information

© The Canadian Public Health Association 2007

Authors and Affiliations

  • L. David Pengelly
    • 1
  • Monica E. Campbell
    • 2
    Email author
  • Chad S. Cheng
    • 3
  • Chao Fu
  • Sarah E. Gingrich
  • Ronald Macfarlane
  1. 1.Department of MedicineMcMaster UniversityHamiltonCanada
  2. 2.Toronto Public HealthTorontoCanada
  3. 3.Meteorological Service of Canada — Ontario RegionEnvironment CanadaCanada

Personalised recommendations