Now you can calculate your organisation's 'nitrogen footprint'

Australian, US and Chinese researchers have collaborated on what is claimed to be the first tool to calculate the ‘nitrogen footprint’ of an organisation — using the University of Melbourne as a guinea pig.

Nitrogen has human and environmental health costs in the hundreds of billions of dollars and is a significant challenge to the sustainability of our society. For example, nitrogen run-off from agriculture in Queensland has resulted in damage to the Great Barrier Reef. Yet according to the researchers, nitrogen pollution is often disguised as other global change issues, such as climate change, which nitrous oxides and nitrogen oxides contribute to, or harmful particulate matter 2.5, which ammonia gas contributes to.

“Our earlier research showed that Australia has a large nitrogen footprint,” said Professor Deli Chen from the University of Melbourne. “At 47 kg of nitrogen per person each year, Australia is far ahead of the US (28 kg of nitrogen per person per year), the second on the leader board of per capita reactive nitrogen emissions driven largely by a diet rich in animal protein and high level of coal use for energy.

“To understand more about Australia’s footprint, we delved into the figures to measure institutional nitrogen footprint.”

Together with Zhejiang University, the University of New Hampshire and the University of Virginia, the University of Melbourne developed a tool that calculates reactive nitrogen — the forms of nitrogen released to the environment from our daily activities. Working on an institutional scale, it takes the sum of individual activities as well as institutional activities, such as powering laboratories and lecture theatres in the case of a university.

According to the new tool, the University of Melbourne has a nitrogen footprint of 139 tonnes of nitrogen, with three factors playing dominant roles: food (37%), energy use (32%) and transport (28%). These results were published in the Journal of Cleaner Production.

“At the University of Melbourne, food plays a dominant role through the meat and dairy consumed,” said University of Melbourne PhD candidate Xia Liang. “Nitrogen emissions from food occurs mainly during the production of food, whereas emissions from energy use is mainly from coal-powered electricity use and emissions from fuel used during business flights.”

The study found that 96% of the nitrogen emissions occurred outside the university’s boundaries. It also found that the detrimental effects are invisible to the person on the ground, with the burden of the pollution often borne far away.

“We also modelled the steps that the university could take to reduce its nitrogen footprint. We found that it could be reduced by 60% by taking action to cut emissions from the three main contributing factors,” said Liang.

“The good news is that if the university implements all the changes detailed in its Sustainability Plan — which includes strategies for reducing carbon emissions, such as transition to clean energy (solar and wind), optimising energy use and buying carbon credits — this would also reduce nitrogen pollution by as much as 29%,” added Professor Chen.

Image credit: ©stock.adobe.com/au/Creativemarc