Air quality during the winter in Québec day-care centers.

Over 90% of 91 day care centers in greater Montréal, Québec exceeded 1000 ppm of CO2 during January through April 1989. Four variables were independent positive predictors of CO2 levels: the density of children in the center; presence of electric heating; absence of a ventilation system; and building age. High levels of CO2 are associated with respiratory tract and other symptoms. Clear standards and inspection policies should be established for day care center air quality.