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Vital Signs

DHMC develops a "green" yardstick for hospitals

John Leigh is the manager of waste and recycling at DHMC.

By Roger P. Smith, Ph.D.

It sounds like it must be a very good, "green" thing for a hospital to calculate its ecological footprint, but what exactly does that mean? It's a process DHMC recently went through, so John Leigh, manager of waste and recycling, is very familiar with the concept. He explains that an ecological footprint is "a measure of natural resources consumed as compared with the Earth's ability to regenerate those resources." To achieve sustainability, a population shouldn't consume more than its proportional share of those resources.

The Earth contains 28 billion productive acres, such as forests and croplands (which excludes deserts, polar areas, and some ocean areas). Dividing that acreage by the Earth's population, 6.8 billion, gives 4.1 acres for each person (which doesn't even factor in the 25 million other species on the planet).

Rise: "We now know that humans are exceeding the biocapacity of the Earth by about 24 percent," says Leigh. "We began to overshoot it in the mid-1980s, and we can reliably predict that the overshoot rate will continue to rise because the population is growing, the per-capita consumption rate is growing, and technology continues to drive our consumption ability."

The calculation of an ecological footprint is a complicated process. Leigh led the development of the spreadsheet-based tool that allowed DHMC to calculate its footprint, thanks to a grant from the Maverick Lloyd Foundation. He broke the institution's environmental impact into seven categories: products, energy, food, waste, transportation, water, and built land.

Gas: Some measurements are firmer than others. For example, experts agree on the greenhouse gas emissions associated with consuming electricity and fuel oil, and DHMC engineers have tracked energy consumption for years. It was much harder to get a handle on the impact associated with the wide variety of products that a major medical center uses-from disposable rubber gloves to massive imaging machines.

The calculation of an ecological footprint is a complicated process.

When all the best measurement models and conversion factors were settled on and applied to DHMC's calculation, the result was 13.8 acres per full-time-equivalent employee-of which there are 5,700 on the Lebanon, N.H., campus. And that doesn't even factor in the resources that all those employees consume at home.

So how does that figure compare to other hospitals? That's a good question, but it's one for which there is, as yet, no answer. DHMC is so far ahead of the curve that no other U.S. hospital has calculated its footprint. Leigh is offering the tool he developed to other hospitals, but no one has completed the process yet.

Meanwhile, Leigh has already begun to apply the results of the calculation. For example, one startling finding was that 32% of the overall impact came from transportation. That includes by patients, visitors, and staff, with staff transportation to and from work the biggest factor. The average one-way commute to work for DHMC employees is nearly 42 miles.

The Medical Center already helps underwrite the local bus system, Advance Transit; has supported the construction of nearby affordable housing; and has taken other steps to minimize commuting. But Leigh would like to see more done in this area. As the Medical Center considers its options, he can now plug data associated with different actions into the ecofootprint tool to learn each action's relative impact.

And best of all, as changes are made, it will be possible to clearly track and not just guess at their impact on the institution's ecological footprint.

Leigh believes a hospital should do all it can do reduce its ecological impact in part because it's unavoidably high. For example, infection-control procedures require the consumption of vast amounts of disposable supplies. The temperature in patient-care areas must be kept comfortably warm in winter and cool in summer. Life-safety features like automated doors and a constant oxygen supply are energy-intensive. Some of the anesthetics used in surgery are greenhouse gasses, so there is a cost to handling them. The list of special needs goes on and on.

Lots: Besides Leigh, one of the people who helped to make DHMC a pioneer in sustainability was his predecessor, Laura Brannen. She now works for a national program called Waste Management Health Care Solutions. "Successful programs," she says, "depend on people to make them happen." Lots of people, she adds. "It was certainly helpful to get buy-in from the top" when DHMC made sustainability a priority 20 years ago, Brannen says, but real success comes when every employee tosses bottles in the recycling bin instead of the trash or considers walking instead of driving to work.

Sometimes the steps toward sustainability are quite literal.

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