A new study by a team at Florida State University estimates that sugar cane fires in South Florida emit harmful particulates in quantities comparable to motor vehicles and are a factor in death rates across the region.
Their work is published in Environmental Health Perspectives, a peer-reviewed journal published by the National Institute of Environmental Health Sciences, an institute of the National Institutes of Health.
“Over the years, there have been numerous complaints from citizens living in and near these camps about frequent ash falls, poor air quality and negative health consequences of smoking,” said Holly Nowell. FSU postdoctoral researcher and lead author of the study. “Although previous studies have shown that fires have a negative impact on air quality, no one has quantified the impacts on mortality.”
Researchers estimate that in all of South Florida, 2.5 people die each year from exposure to sugarcane smoke.
Across the state of Florida, more than 2 million acres are burned each year through prescribed burns. Most of this serves to mitigate the risk of fires and maintain habitats for some species. However, around 400,000 acres of sugarcane fields are also burned before harvest to remove unsweetened vegetation on the sugarcane stalk.
Most of Florida’s burning sugarcane is concentrated around the southern shore of Lake Okeechobee in the towns of Belle Glade, Clewiston, and Pahokee. Sugar cultivation is a major economic engine for the area, employing more than 14,000 people and generating approximately $ 800 million in revenue annually.
Burning this vegetation produces smoke with harmful particles that are less than 2.5 microns in diameter and can be inhaled deep into the lungs. Previous studies have shown that these particles are associated with health problems such as asthma, lung cancer, cardiovascular problems, and even early death.
The team found that mortality rates from this exposure are nearly 10 times higher for residents living near the fields than outside the surrounding area.
The research team used measurements from multiple sources, including satellite sensors and ground monitoring, to estimate burn-related exposures. They also created estimates of daily sugarcane fire emissions based on combustion permits issued by the state of Florida and examined data on demographic and health impact to examine the causes of mortality.
They found that sugar cane fires produced 5,100 tons of these small 2.5-micron particles per year. By comparison, Florida’s on-road motor vehicles emit approximately 6,100 tons of these particles.
The researchers pointed out that while these numbers are troubling, air quality in the region complies with current U.S. air quality standards, as do particle pollution totals.
“We started this work because we wanted to better understand the public issues and controversies surrounding the Florida sugarcane fires and smoke,” said Associate Professor Christopher Holmes. “On the one hand, some residents in the sugar cane region around Lake Okeechobee are concerned about asthma and respiratory health caused by sugar cane smoke. On the other hand, the sugar cane industry and its supporters have pointed to measurements showing that average airborne particle pollution falls within federal guidelines. “
Holmes and Nowell said this research was a stepping stone to a broader conversation about the health and air quality impacts of burning sugarcane and that they hope their work will simply be used as environmental agencies and lawmakers continue to review the practice and create guidelines for burning.
“Whether or not burning sugarcane should continue is a hot topic with people on both sides,” Nowell said. “We need more studies evaluating the air quality and health impacts of this practice.”
Other researchers in this study are former FSU graduate student Charles Wirks, FSU Associate Professor of Public Health Chris Uejio, Maria Val Martin of the University of Sheffield, and Aaron van Donkelaar and Randall Martin of Washington University in St. Louis.
The study was supported by NASA’s atmospheric composition modeling and analysis program.