Proposition of Lags and Variables for a Cold-Health Watch and Warning System in the Province of Quebec

Abstract

Extreme cold and hot weather events have serious impacts on human life and health, and have been shown to increase daily mortality. The heat waves of recent years led many countries to establish their heat-health watch and warning systems (HHWWS) to prevent the effects of extreme heat. In spite of known impacts, there have not been many studies that concern warning systems for cold. In temperate regions, winter mortality is generally higher than the rest of the year. This is especially true for the province of Quebec, where the winter is long and usually very cold. Thus, it is of interest to establish a cold-health watch and warning system. However, cold studies are a bit different than heat studies. On the one hand, the delay between exposure to high ambient temperatures and mortality is short, whereas the effects for extremely cold temperatures is usually much longer (for example, 21 days in studies of associations between meteorological variables and cold-health outcomes). A watch and warning system concerns rather a high excess mortality caused directly by meteorological variables such as the daily minimum and maximum temperatures. However, since the direct effects of these meteorological variables decrease with time, it will be impossible to take a very long lag for a watch and warning system. On the other hand, a HHWWS usually takes into account temperature and humidity, but in order to establish a cold-health watch and warning system, we have to consider different meteorological variables. Therefore, the objectives of this study are to: 1) determine the lag for the cold-health watch and warning system (based on an approach from HHWWS), and 2) propose relevant meteorological variables for this system. To evaluate the performances of this system, it is applied to the province of Quebec. It is a good start to establish a general and elaborate cold-health watch and warning system in this province.