Nitrogen-Related Air Pollutants, Climate Change Need Study in Tandem with Human Health Impacts, Colorado State University Scientist Says

Note to Reporters: A photo of Jennifer Peel and a full copy of the paper are available with the news release at

Nitrogen-related air pollutants that come from sources such as cars, power plants, fertilizer and animal wastes have an impact on human health that needs to be considered together with likely impacts of global climate change, according to a new paper by a Colorado State University professor and others.

Jennifer Peel, associate professor of epidemiology and environmental health in the College of Veterinary Medicine and Biomedical Sciences at CSU and four colleagues from an NSF working group, took a broad look at nitrogen in the environment in the review article, which now appears online in the journal Biogeochemistry.

Their challenge – undertaken during a Fort Collins workshop in 2011 – was to think about human health impacts likely to result from the interaction of nitrogen-related air pollutants, such as ozone, particulate matter (PM), nitrogen oxides, and ammonia, with climate change. They reviewed evidence on the subject and evaluated where further research could be useful. The report also was submitted as part of a larger effort for the National Climate Assessment.

“The state of knowledge regarding the likely impact of the interaction of nitrogen and climate change on ambient air quality and human health contains some critical gaps,” the scientists conclude in the paper.

“We know that both climate change and nitrogen-related air pollutants have potentially serious independent impacts on human health,” Peel said. “So based on what we know, rather than think about each factor in isolation, the challenge was to evaluate how these two environmental phenomena will interact to impact human health and where more research is needed on this topic.”

Areas impacting the environment and health that need further study, according to the scientists:

Greater exposure to ozone: Climate change will likely make summers warmer and longer, increasing our exposure to ozone. Ozone is dependent on those warm days with lots of UV radiation. Nitrogen emissions from increased air conditioning also can feed into ozone formation.

Increased frequency and severity of wildfires: Drought is becoming more extreme and changing the frequency of wildfires and where they occur, thereby increasing human exposure to fire-related air pollutants. Increasing nitrogen in the environment also could promote growth of fire-prone plants.

Increased pollen emissions: Both climate change and environmental nitrogen could change the timing and the magnitude of pollen emissions from plants, possibly extending the period of the pollen season. Nitrogen-related ambient air pollutants can make pollen allergies worse.

Increased heat waves: The frequency and length of heat waves is likely to increase with global climate change. Some evidence suggests that air pollution and heat waves are even more deadly when experienced in combination with each other, particularly for vulnerable populations such as the elderly and those without access to air conditioning.

Peel’s co-authors included scientists from the U.S. Environmental Protection Agency and the Georgia Institute of Technology.