Reactive nitrogen emissions contribute to greenhouse gases, as well as air and water pollution. For the first time, researchers from McGill University have calculated Canada’s nitrogen footprint (akin to a carbon footprint) – at both national and provincial levels. They looked at the three primary sectors that contribute nitrogen to the environment to calculate the annual average nitrogen footprint: food production and consumption, wastewater treatment, and fossil fuel use. There were some surprises when they analyzed their results.