A new environmental scorecard says Canada's biggest cities have lower scores than most small and medium-sized municipalities, but a closer look at the data reveals some surprises. The study, published Tuesday in the journal Environment International, rates 30 of the country's largest cities and towns on nine indicators related to health, including air quality, heat and cold waves, ultraviolet radiation, and access to green spaces. The results are compiled in the new Canadian Environmental Quality Index, produced by Dalhousie University in Halifax.