We do not hear much about nitrogen pollution, but it poses a serious global problem. While nitrogen is the most abundant gas in the atmosphere and extremely stable, human activities have converted nitrogen to reactive forms. The natural conversions of nitrogen occur by biological nitrogen fixation, biomass burning and lightning. Over 100 years ago, an industrial transformation of nitrogen gas was discovered (often described as one of the greatest breakthroughs of the 20th century): the reaction of nitrogen with hydrogen to produce ammonia. Ammonia is used to make nitrogen fertilizer – lots of it! While this has been critical for the growth of food crops, more than half of applied nitrogen fertilizers do NOT feed plants, but leak into air or water. In short, the massive use of fertilizers has changed the amount of reactive nitrogen in the global ecosystem.
Similar to other natural cycles, the nitrogen cycle has been disrupted by human activities. Chemical nitrogen fertilizers create gas emissions of ammonia, nitrogen oxides and nitrous oxides. Fertilizers release nitrates to natural water bodies, which leads to overgrowth of plants, algae and microorganisms. In turn, less oxygen is available for aquatic organisms, causing death and decay -polluted waters. This deterioration renders these ecosystems less able to handle consequences of climate change and also releases additional greenhouse gases. Nitrous oxide is a gas that has increased in the atmosphere over the past decades and is a consequential greenhouse gas. It has a greater global warming potential than carbon dioxide. Increases in these forms of nitrogen in the environment absolutely impact human health, in forms such as respiratory illnesses and heart disease.
A true effort to monitor the release of reactive nitrogen is moving forward in Scotland. It focuses on geographic areas that have been identified as vulnerable. Scientists working on the problem of nitrogen pollution suggest that nitrogen conversions are complex, often ignored and require a change in the perceptions that farmers and their ability to produce food are under attack. Like so many environmental problems generated by human activities, the emphasis must be the health of all people and all creation. On a personal level, if you hire a company to spray your lawn with fertilizer and pesticide, you are contributing to the nitrogen imbalance problem. This is an easy fix and something to consider for taking part in the solution.
Julie Peller Ph.D. is an environmental chemist (Professor of Chemistry at Valparaiso University ) and she leads the Environmental Ministry at Nativity of Our Savior in Portage IN. Julie has been writing a weekly column for church bulletins for the past ~6 years called the Green Junction and is helping to move the call of Laudato Si to action forward. Her Research Interests are in Advanced oxidation for aqueous solutions, water quality analyses, emerging contaminants, air quality analyses, Lake Michigan shoreline challenges (Cladophora, water, and sediment contaminants), student and citizen participation in environmental work.