Smoking is the major cause of preventable death in Canada, accounting for more than 45,000 premature deaths per year and 30 per cent of all cancer deaths. Most smokers begin to smoke as teenagers, and tobacco advertising and promotion are among the main motivators for tobacco use, especially in youth. Currently, tobacco companies are spending the majority of their marketing dollars in retail stores, compared to any other advertising venue. Since most teenagers shop at convenience stores at least once a week, adolescents are routinely exposed to tobacco advertising. Little research has examined the extent and impact of these “Point of Purchase” (POP) activities in Canada. Helen Hsu is studying the links between smoking prevalence among youth and environmental influences, including POP advertising, pricing, signage and retail locations. She is using Geographic Information System technology to gather and analyze social-demographic, economic and geographic information. Her work could help explain the impact of tobacco industry activities on adolescent tobacco use across Canada, and provide insight into the effectiveness of tobacco control strategies in schools and communities. This information will be useful for setting public health policies and developing tobacco control programs.