Asthma Hospitalizations Dropped after Louisville Power Plants Retired Coal or Installed Better Emission Controls
After four Louisville, Kentucky, coal-fired power plants either retired coal as their energy source or installed stricter emission controls, local residents’ asthma symptoms and asthma-related hospitalizations and emergency room visits dropped dramatically, according to research published today in Nature Energy.
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The study was conducted by Columbia University Mailman School of Public Health, Propeller Health, University of California Berkeley, Harvard TH Chan School of Public Health, University of Texas Austin, Colorado State University, Louisville Metro Department of Public Health and Wellness, Louisville Metro Office of Civic Innovation and Technology, the Christina Lee Brown Envirome Institute and Family Allergy & Asthma.
Coal-fired power plants are known to emit pollutants associated with adverse health effects, including increased asthma attacks, asthma-related ED visits and hospitalizations.1-5 In 2014, coal-fired power plants accounted for 63% of economy-wide emissions of sulfur dioxide (SO2) in the U.S.6 Historically, Kentucky has ranked among the top five states in the U.S. for emissions from power generation.7
Starting with a pilot in 2012, the city of Louisville embarked on a project called AIR Louisville, which aimed to use data from Propeller Health’s digital inhaler sensors to gain insights into the impact of local air quality on the burden of respiratory disease in the community. The public-private collaboration equipped more than 1,200 Louisville residents with asthma and COPD with Propeller sensors, which attach to patients’ existing inhalers and deliver insights on medication use, symptoms and environmental factors to the Propeller app on their smartphone.
“AIR Louisville brought together local government, public and private partners and residents for a common mission: to leverage local data to make our city better and more breathable,” said Louisville Mayor Greg Fischer. “We are still seeing the results of AIR Louisville in this research, which demonstrates the public health impact of retiring coal as an energy source or further controlling coal-fired emissions.”
Between 2013 and 2016, one coal-fired power plant in the Louisville area retired coal as an energy source, and three others installed stricter emission controls to comply with regulations from the U.S. Environmental Protection Agency. Researchers took advantage of these circumstances to analyze the impact of the coal-fired power plant energy transitions on residents’ respiratory health, using data from Propeller and local hospitals to assess how asthma-related symptoms, ED visits and hospitalizations changed over time.
The study looked at the frequency of the total number of asthma-related E.R. visits and hospitalizations per ZIP code in Jefferson County, as well as the frequency of asthma rescue medication use among 207 people. Data on rescue medication use for asthma was used as a proxy for patients’ symptoms, as patients use their rescue medication for acute relief from symptoms such as coughing and shortness of breath.
“This study was unique in its ability to measure asthma morbidity based on both hospitalizations and daily symptoms, and to leverage an abrupt change in environmental exposure to more directly attribute changes in asthma exacerbation to changes in coal-fired power plant emissions,” said Joan Casey, PhD, lead author of the paper and assistant professor of environmental health sciences at Columbia University Mailman School of Public Health.
The researchers found that energy transitions in the spring of 2015 resulted in three fewer hospitalizations and ED visits per ZIP code per quarter in the following year, when comparing areas that had high coal-fired power plant emission exposure prior to the transition to those with lower levels. This translates into nearly 400 avoided hospitalizations and ED visits each year across Jefferson County.
At the individual level, the Mill Creek SO2 scrubber installed in June 2016 was associated with a 17 percent immediate reduction in rescue medication use, which was maintained thereafter. The study also found the odds of having high rescue use throughout a month (on average more than four puffs per day) was reduced by 32 percent following the June 2016 energy transition.
“This is the first study to use digital inhaler sensors to understand the health effects of reducing emissions from coal-fired power plants,” said study author Meredith Barrett, PhD, head of population health research for Propeller Health. “We hope this evidence will encourage government officials to support stricter standards when regulating coal-fired power plants and encourage us towards cleaner power options, thereby protecting the health of the people who live near these facilities.”
The main funding for the project was provided by the Robert Wood Johnson Foundation. Support was also provided by the Foundation for a Healthy Kentucky, Norton Healthcare Foundation, Owsley Brown Charitable Foundation, the American Lung Association, the National Institute of Environmental Health Sciences and the U.S. Environmental Protection Agency. The contents of the research and related materials are solely the responsibility of the grantee and do not necessarily represent the official views of the USEPA or the Robert Wood Johnson Foundation. Lead author Joan Casey, PhD, declares no financial interest in Propeller Health.
- Zheng, X.-y. et al. Association between air pollutants and asthma emergency room visits and hospital admissions in time series studies: a systematic review and meta-analysis. PLoS One 10, e0138146 (2015).
- Orellano, P., Quaranta, N., Reynoso, J., Balbi, B. & Vasquez, J. Effect of outdoor air pollution on asthma exacerbations in children and adults: Systematic review and multilevel meta-analysis. PLoS One 12, e0174050 (2017).
- Williams, A. M., Phaneuf, D. J., Barrett, M. A. & Su, J. G. Short-term impact of PM2.5 on contemporaneous asthma medication use: Behavior and the value of pollution reductions. Proc. Natl. Acad. Sci. USA 116, 5246-5253 (2019).
- U.S. Environmental Protection Agency. Integrated Science Assessment for Oxides of Nitrogen-Health Criteria, <http://ofmpub.epa.gov/eims/eimscomm.getfile?p_download_id=526855> (2016).
- U.S. Environmental Protection Agency. Integrated Review Plan for the Primary National Ambient Air Quality Standard for Sulfur Dioxide. EPA-452/R-14-007, <https://www3.epa.gov/ttn/naaqs/standards/so2/data/20141028so2reviewpla ...> (2014).
- Massetti, E. et al. Environmental Quality and the US Power Sector: Air Quality, Water Quality, Land Use and Environmental Justice. Prepared by: Oak Ridge National Laboratory for the U.S. Department of Energy, <https://www.energy.gov/sites/prod/files/2017/01/f34/Environment%20Base ...> (2017).
- U.S. Environmental Protection Agency. National Emissions Inventory, <https://www.epa.gov/air-emissions-inventories/2011-national-emissions- ...> (2011).
About Propeller Health
Propeller Health is a leading digital health company dedicated to making life better for every person with chronic respiratory disease. Propeller creates products to more effectively treat chronic respiratory disease and improve clinical outcomes for patients through connectivity, analytics, and companion digital experiences. The Propeller platform is used by patients, physicians and healthcare organizations in the United States, Europe and Asia. Propeller Health is a wholly owned subsidiary of ResMed (NYSE: RMD, ASX: RMD). For more information, visit www.propellerhealth.com.
About Columbia University Mailman School of Public Health
Founded in 1922, the Columbia University Mailman School of Public Health pursues an agenda of research, education, and service to address the critical and complex public health issues affecting New Yorkers, the nation and the world. The Columbia Mailman School is the seventh largest recipient of NIH grants among schools of public health. Its nearly 300 multi-disciplinary faculty members work in more than 100 countries around the world, addressing such issues as preventing infectious and chronic diseases, environmental health, maternal and child health, health policy, climate change and health, and public health preparedness. It is a leader in public health education with more than 1,300 graduate students from 55 nations pursuing a variety of master's and doctoral degree programs. The Columbia Mailman School is also home to numerous world-renowned research centers, including ICAP and the Center for Infection and Immunity. For more information, please visit http://www.mailman.columbia.edu.