Nitrogen Calculator

Scientists at Lancaster, Virginia and Oxford universities have produced a web-based tool that allows anyone living in the UK to see their own ‘nitrogen footprint’.

The tool, known as the N-Calculator, asks users to put in information so that it can calculate the likely effect that the food that they eat or the transport they take has on the environment in terms of nitrogen pollution. It is hoped that the tool will lead to more people choosing sustainable ways of living.

Scientists have warned that reactive nitrogen pollution is already a major environmental problem that is causing significant damage to air and water quality across the UK. Nitrogen runoff from farms and man-made effluents are largely responsible for algal blooms that affect river systems, whilst atmospheric nitrogen pollution is leading to significant losses of biodiversity. Most of the nitrogen pollution arises out of agricultural processes used in the growing of crops or grazing of animals, they warn. In addition, a significant proportion of the average UK nitrogen footprint comes from vehicle emissions.

‘Nitrogen is essential for growing crops for food or high quality grass for cattle, as any farmer knows,’ said Paul Whitehead, Professor of Water Science at the School of Geography and the Environment, and Director of the NERC-funded Macronutrients Cycles Programme. ‘However, the widespread use of nitrogen fertilizer to boost crop production has resulted in a runoff of excess nitrogen from farms into our rivers, lakes and groundwaters.’

The researchers used publicly available data such as national atmospheric data, national land use and farm statistics, to make the calculations. The N-Calculator website also makes recommendations for how to lessen your ‘nitrogen footprint’. Lifestyle choices affect your nitrogen footprint: reducing your nitrogen footprint means cutting back on road and air travel, choosing renewable energy and, most importantly, altering the balance of the foods contained in your diet.

‘Unlike your carbon footprint, what you eat is the most important factor determining your nitrogen footprint,’ said Dr Carly Stevens of Lancaster University. ‘By altering the amount and type of food that you eat, you can make a big difference to your impact on the environment.’

The tool, first developed in the US, has been updated and adapted for UK users by researchers from Lancaster University under a project funded by the NERC Macronutrient Cycles programme at Oxford. The device was originally created by award-winning scientist James N Galloway and his research colleagues, Allison Leach, at the University of Virginia, Albert Bleeker of ECN and Jan Willem Erisman of the Louis Bolk Institute, both of The Netherlands.