A recent study has found that if the U.S. healthcare system were its own country, it would rank 13th in the world for greenhouse gas emissions.

Expectedly, the most expensive healthcare system in the world uses the most amount of energy. The study, published June 9 in the scientific journal PLOS ONE, found the U.S. healthcare system is responsible for 8 percent of the nation's greenhouse gas emissions, from heating, electricity and energy-intensive goods and services. But this information has yet to be analyzed for their impact on public health.

Yale's Jodi Sherman, MD, and first author Matthew Eckelman of Northeastern University calculated the total emissions of different pollutants produced by the healthcare sector over a decade using national health expenditure data. Analyzing direct emissions from hospitals and clinician's offices, along with emissions generated by suppliers of energy, goods and services, the study linked healthcare-related emissions to global warming, ozone depletion, respiratory disease from air pollutants and cancer.

Greenhouse gas emissions from the healthcare field grew 30 percent in 10 years, accounting for 9.8 percent of the national total in 2013. The study estimated that health damages from the pollutants at 470,000 "disability adjusted life years" (DALYs) which is comparable to deaths each year related to preventable medical errors.

"While some pollution is currently inevitable in our efforts to safely care for patients, there is a tremendous amount of waste in our healthcare system," said Sherman. "People are trying to reduce waste from a cost perspective. But there is a public health perspective as well that is important. Protecting public health is also an issue of patient safety."