Plume Chasers: Landfill Fire Sparks Research
On May 26, 2012, Diana Thrift was eating dinner with her family when she learned that a fire was burning at the Iowa City Landfill, just one mile away. She rushed outside and saw dramatic, incredibly bright orange-red flames. “For a long time, flames filled the horizon,” she says.
The fire at the landfill started on Memorial Day weekend and burned on for weeks, consuming shredded tires in the landfill’s liner system and creating smoke that was dangerous as well as foul-smelling. According to estimates by the city of Iowa City, the fire burned the equivalent of 1.3 million tires in the 7.5-acre fire area.
Where There’s Smoke, There’s Danger
Landfill fires are difficult to control, and often spew highly toxic emissions into the atmosphere. According to air samples taken two miles from the fire and analyzed by University of Iowa Assistant Professor of Chemistry Elizabeth Stone, the Iowa City smoke plume contained polycyclic aromatic hydrocarbons, or PAHs, at concentrations 100 times higher than normal. PAHs have been shown to cause tumors and reproductive problems in lab animals. Volatile organic compounds (VOCs), such as benzene and benzo[a]pyrene, have also been detected in the open burning of tires. According to the EPA, VOCs can cause a variety of symptoms, including headaches, loss of coordination, and nausea; damage to the liver, kidneys, and central nervous system; and eye, nose, and throat irritation.
Thrift, who suffers from allergies and sensitivity to smoke, became worried by the plume of oily black smoke that darkened the sky for weeks. “The smell was terrible,” she remembers, “And the huge black smoke plume looked and felt menacing.” Because she spends a lot of time outdoors, Thrift says the situation caused her a lot of anxiety. “It kept going on and on and on,” she says. “I knew it was toxic smoke, very polluting to the environment. It felt like we were having an environmental disaster.”
For IIHR Research Engineer Charles Stanier and his research partners Stone and Scott Spak, news of the fire was a call to action. Stanier deployed his group’s mobile atmospheric sampling unit shortly after the first reports of fire. Stone was already sampling for another project, and increased her sample coverage, and Spak began creating a smoke forecast model. They hoped to offer the Johnson County Health Department information about the smoke plume’s movements, which could help concerned residents like Thrift.
Stanier’s mobile sampling unit, which was being prepared for another research project, is equipped with instruments that make air-quality readings every 10 seconds. The instruments sample for carbon monoxide, carbon dioxide, and sulfur dioxide, and can also detect particle size. The trailer was moved four times during the fire to capture data within the smoke plume itself, while stationary sampling instruments at two additional locations also made particulate and gaseous measurements.
Forecasting the Plume
Using a weather forecasting system developed at the University of Iowa’s Center for Global and Regional Environmental Research (CGRER), the team predicted hourly smoke concentrations at 500-meter resolution throughout Iowa City and Johnson County, and generated maps showing where the smoke was expected to go the next day. Spak led this part of the effort, and the team provided these forecasts to Johnson County public health and emergency management officials, offering a timely, valuable public health response to an extreme air pollution event.
Stanier, who is also an associate professor of chemical and biochemical engineering, conducts lab experiments and field sampling of air pollution, particularly aerosol particles. He also uses computer simulations to understand atmospheric aerosol chemistry, and the health effects of airborne contaminants. He recently received the National Science Foundation’s CAREER Award for his work on ultra-fine particle generation.
Stanier says the team’s efforts during the fire made sense from a public service standpoint as well as a research perspective. “I really do want to understand the atmosphere and its effect on health and the environment,” Stanier says. “This extreme event made it possible for us to learn more about the movements and makeup of smoke from a fire like this one, while also serving a vital public health need.” He hopes that the team’s work on the fire can help provide a response template for other communities that experience a landfill or industrial fire like the Iowa City event.
Stanier says his overarching goal is to develop models that can more accurately predict the concentrations, sizes, and proportions of particles in the atmosphere. If he and his team can achieve that, Stanier says, they will have succeeded.