Tracking and Measuring Greenhouse Gas Emissions

Greenhouse Gases 101

Gases that trap heat in the atmosphere are often called greenhouse gases.  Some greenhouse gases such as carbon dioxide occur naturally and are emitted to the atmosphere through natural processes and human activities (i.e. volcano eruptions). Other greenhouse gases are created and emitted solely through human activities. The six categories of greenhouse gases typically referred to by most inventories include carbon dioxide, methane, nitrous oxide and the fluorinated gases: sulfur hexafluoride, hydroflurocarbons (HFCs) and perfluorocarbons (PFCs).

A brief description of the kinds of activities that drive production of these greenhouse gases:

Carbon Dioxide (CO2): Carbon dioxide enters the atmosphere through the burning of fossil fuels, incineration and landfill disposal of solid waste, trees, wood products, and also as a result of other chemical reactions (for example the, manufacturing of cement). Carbon dioxide is also removed from the atmosphere (or “sequestered”) when it is absorbed by plants as part of the biological carbon cycle.

Methane (CH4): Methane is emitted during the production and transport of coal, natural gas, and oil. Methane emissions also result from the decay of organic waste, and is a major byproduct of municipal landfills. Agriculture is also a major source of methane generated as a waste product by livestock.  

Nitrous Oxide (N2O): Nitrous oxide is emitted during agricultural and industrial activities, as well as during combustion of fossil fuels and solid waste. Nitrous oxide is also used as a component of anesthesia medications.

Fluorinated Gases: Hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride are synthetic, powerful greenhouse gases that are emitted from a variety of industrial processes. Fluorinated gases are sometimes used as substitutes for ozone-depleting substances (i.e., CFCs, HCFCs, and halons). These gases are typically emitted in smaller quantities, but because they are potent greenhouse gases, they are sometimes referred to as High Global Warming Potential gases (“High GWP gases”). Fluorinated ethers including the common anesthesia gases sevoflurane, desflurane and isoflurane are derivatives of hydrofluorocarbons and have significant global warming potential (GWP).

The unregulated direct release of volatile anesthetic gases—known in healthcare as waste anesthetic gases or WAGs—are an emission unique to healthcare.  The most widely used potent inhaled agents (sevoflurane, desflurane and isoflurane, and nitrous oxide,) undergo very little in vivo metabolism in clinical use.  They are exhaled and then scavenged by anesthesia machines with little or no additional degradation, and are typically vented directly into the atmosphere along with medical gases. The human body metabolizes less than 5% of the anesthesia gas during a procedure, with the remaining 95% exhausted to the outdoor environment.  These emissions fall under a hospitals’ Scope I emissions.[i]

Tracking GHG Emissions

Because the public health and environmental impacts of climate change are becoming more clear daily, there is a growing call to measure and track—and eventually reduce — organizations’ greenhouse gas emissions. Before an organization can move forward with tracking its release of GHGs, it is important to understand the terminology used when tracking emissions. Greenhouse gas emissions are typically categorized into three subsets: Scope I, Scope II and Scope III emissions.

Scope I

Emissions are direct GHG emissions from sources that are owned or controlled by the hospital. Scope I can include emissions from fossil fuels burned on site, emissions from hospital-owned or hospital-leased vehicles, and other direct sources.

Scope II

Emissions are indirect GHG emissions resulting from the generation of electricity, heating and cooling, or steam generated off site but purchased by the hospital, and the transmission and distribution (T&D) losses associated with some purchased utilities (e.g., chilled water, steam, and high temperature hot water).[ii]

Scope III

Emissions include indirect GHG emissions from sources not owned or directly controlled by the hospital but related to the hospitals’ activities such as vendor supply chains, delivery services, outsourced activities, employee travel and commuting, T&D losses associated with purchased electricity, and site remediation activities.[iii]

Image from Federal Facilities Environmental Stewardship and Compliance Assistance Center: http://www.fedcenter.gov/Photos/index.cfm?id=16810

Tools for Tracking GHG Emissions

There are a variety of tools available to the healthcare sector for tracking and measuring GHG emissions. These tools range from calculators designed for general industry to site-specific GHG audits performed by consultants. Practice Greenhealth will highlight several of the most common tools used by its healthcare members to track and measure GHG emissions:

EnergyStar’s Portfolio Manager
Portfolio Manager calculates your building's greenhouse gas emissions (including carbon dioxide, methane, and nitrous oxide) from on-site fuel combustion and purchased electricity and district heating and cooling. Portfolio Manager also enables tracking of avoided emissions from any Renewable Energy Certificates. While the emissions calculations are based on the amount of energy your building consumes, they have no bearing on its energy performance rating. The methodology for calculating greenhouse gas emissions in Portfolio Manager was designed to be consistent with the Greenhouse Gas Protocol developed by the World Resources Institute and World Business Council for Sustainable Development, and is compatible with the accounting, inventory and reporting requirements of EPA's Climate Leaders program, as well as other state and NGO registry and reporting programs. For more detailed information on emissions calculations, refer to the Technical Description of Greenhouse Gas Emission Calculations ( 141KB ).[iv]

EPA Climate Leaders
Climate Leaders is an EPA industry-government partnership that works with companies to develop comprehensive climate change strategies. Participating companies commit to reduce their impact on the global environment by completing a corporate-wide inventory of their greenhouse gas emissions based on a quality management system, setting aggressive reduction goals, and annually reporting their progress to EPA. Through program participation, companies create a credible record of their accomplishments and receive EPA recognition as corporate environmental leaders.[v]

GHG Reporting Protocol Initiative
GHG Reporting Protocol is the most widely used international accounting tool for government and business leaders to understand, quantify, and manage greenhouse gas emissions. The GHG Protocol, a decade-long partnership between the World Resources Institute and the World Business Council for Sustainable Development, is working with businesses, governments, and environmental groups around the world to build a new generation of credible and effective programs for tackling climate change.[vi]

Climate Registry Information System (CRIS)
The Climate Registry Information System (CRIS) is The Registry’s online greenhouse gas (GHG) calculation, reporting, and verification tool. CRIS also provides public access to The Registry’s verified emission reports.[vii]

Greenhouse Gas Management Institute
The Greenhouse Gas Management Institute aims to address climate change by building and supporting a global community of experts with the highest standards of professional practice in measuring, accounting, auditing and managing greenhouse gas emissions[viii]. The organization provides education and training to individuals on how to develop and reduce an organization’s carbon footprint.