Photo by: Courtesy of PSE Healthy Energy

Home is Where the Pipeline Ends

06/28/2022 | Environmental Science & Technology

Every day, millions of Americans rely on natural gas to power appliances such as kitchen stoves, furnaces, and water heaters, but until now very little data existed on the chemical makeup of the gas once it reaches consumers.

A study led by Visiting Scientist, Drew Michanowicz, at Harvard T.H. Chan School of Public Health found that gas used in homes throughout the greater Boston area contains at least 21 different hazardous air pollutants that may impact air quality and health, wherever natural gas is leaked. The research, published in Environmental Science & Technology, is the first to test for health-damaging air pollutants in unburned natural gas when it is used in our homes.

Researchers collected over 200 unburned natural gas samples from 69 unique kitchen stoves and building pipelines across Greater Boston between December 2019 and May 2021. The research team included PSE Healthy Energy, Atmospheric and Environmental Research AER, Gas Safety Inc., Boston University, and Home Energy Efficiency Team (HEET).

Key Takeaways

  • Consumer-grade natural gas supplied to Massachusetts contains varying levels of at least 21 different hazardous air pollutants, as defined by the U.S. EPA, including benzene, toluene, ethylbenzene, xylene, and hexane.
  • Concentrations of hazardous air pollutants in natural gas varied depending on location and time of year, with the highest concentrations found in the winter.
  • Based on odorant concentrations, small leaks can be undetectable by smell – leaks up to 10 times naturally occurring levels may be undetectable, equating to a methane concentration of about 20 parts per million.

Actions that policymakers and individuals can take to mitigate health risks posed by natural gas used in homes:

Policy Actions

  • Gas pipeline companies could be required to measure and report more detailed information on the composition of natural gas, specifically differentiating non-methane volatile organic compounds such as benzene and toluene.
  • Gas utility providers could be required to routinely measure and report natural gas odorant content to customers similar to informational postings often produced by interstate gas pipeline companies.
  • State regulations could require direct measurement of leaked, unburned natural gas in ambient air to be included in emissions inventories and to better determine public health risks.
  • The Consumer Product Safety Commission has the authority to set performance standards for gas stoves and ventilation hoods to limit air pollutant emissions.
  • Home inspectors and contractors could be required to perform natural gas-appliance leak detection surveys or to measure for ppm-range methane, similar to radon tests done prior to the completion of a real estate transaction.
  • Given the importance of odorants in detecting gas leaks, federal natural gas odorization regulations could be updated so that natural gas is odorized to meet much lower detection levels than the current 1/5th the lower explosion limit (detectable at ~1% methane).

Individual Actions

  • Because small leaks may evade our sense of smell, getting an in-home natural gas leak detection survey performed by a licensed plumber or heating, ventilation, and air conditioning (HVAC) contractor can verify that no small leaks are present.
  • Increasing ventilation is one of the most accessible and important actions to reduce sources of indoor pollution. Opening windows and turning on a vent that exhausts to the outside when cooking are simple steps that can lower the risk of indoor exposure.
  • If you smell gas, exit the building and then immediately call your gas company to assess whether there is a leak in or nearby your home.

Read the study

Read the press release

Authors

“Home is Where the Pipeline Ends: Characterization of Volatile Organic Compounds Present in Natural Gas at the Point of the Residential End User” by Drew R. Michanowicz, Archana Dayalu, Curtis L. Nordgaard, Jonathan J. Buonocore, Molly W. Fairchild, Robert Ackley, Jessica E. Schiff, Abbie Liu, Nathan G. Phillips, Audrey Schulman, Zeyneb Magavi, and John D. Spengler, https://doi.org/10.1021/acs.est.1c08298

Home is Where the Pipeline Ends

Our study is the first to test for health-damaging air pollutants in unburned natural gas where it is used: in our homes.

Read Now

New tool helps businesses, schools, evaluate indoor ventilation

The Healthy Buildings Program at Harvard T.H. Chan School of Public Health released a new online calculator to help people who are using carbon dioxide (CO2) monitors understand ventilation rates in indoor spaces and determine a maximum safe level.

Read Now

Rethinking building design for the health of people and the planet

Adele Houghton, DrPH ’23, is creating new tools to help real estate teams become more responsive to the health needs of their buildings’ occupants and the surrounding communities.

Read Now

2021 Lancet Countdown on Health and Climate Change: U.S. Policy Report

Our response to climate change must prioritize and optimize health and equity. We can improve health through climate actions that reduce our use of fossil fuels.

Read Now

Methane Reductions in the Oil and Gas Sector can Protect Public Health

A literature review examines the last ten years of research on methane and health-damaging air pollutant emissions from the oil and gas industry.

Read Now

An 80x30 Clean Electricity Standard: Carbon, Costs, and Health Benefits

The energy, economic, environmental, and health outcomes of an illustrative clean energy standard design that reaches 80% clean electricity by 2030.

Read Now

Negative impacts of burning natural gas and biomass have surpassed coal generation in many states

A new inventory of air pollution impacts from stationary sources over the past decade shows this trend may continue.

Read Now

Pennsylvania setback regulations for fracking do not prevent setback incidents

The first study to look at the effectiveness of PA's statewide setback regulations and identify the potential risks and exposures for people living near fracking or UNG wells.

Read Now

Companies are promising to remove carbon — what about frontline communities?

In an op-ed, our researcher Jonathan Buonocore argues why companies' climate pledges must include emissions reduction strategies to protect frontline communities.

Read Now

Pollution from fossil fuel combustion deadlier than previously thought

Fine particulate pollution from fossil fuel combustion was responsible for one in five early deaths worldwide in 2018, with vulnerable groups at greatest risk.

Read Now

What the Supreme Court's Stunning Rulings Mean for Your Health

Our Director weighs in on the health impacts of the Supreme Court decision to limit the power of EPA.

Read Now

Gas Piped Into Homes Contains Benzene and Other Risky Chemicals, Study Finds

Our study analyzed 234 samples of unburned natural gas in homes throughout the Greater Boston Area.

Read Now

Scientists tested the natural gas used in kitchen stoves around Boston. They found dangerous chemicals.

Our scientists found 21 chemicals designated as hazardous by EPA.

Read Now

Natural Gas Used in Homes Contains Hazardous Air Pollutants

Our study finds that natural gas used in homes throughout the Greater Boston area contains varying levels of hazardous air pollutants.

Read Now

Fossil fuel extraction is harming Indigenous communities, say experts

Fossil fuel production causes environmental health effects in Indigenous communities, and leadership from frontline Indigenous activists has been critical in fighting these environmental injustices, according to experts who spoke at a Harvard Chan School event.

Read Now

Health consequences of using biomass for energy

Burning biomass has significant public health and environmental justice consequences, according to a recent opinion piece co-authored by Harvard Chan School’s Jonathan Buonocore.

Read Now

Biomass is not health neutral

Our Research Scientist Jonathan Buonocore writes that even as Congress declares biomass carbon neutral in the latest spending bill, burning it puts thousands of lives at risk.

Read Now

Rethinking building design for the health of people and the planet

Adele Houghton, DrPH ’23, is creating new tools to help real estate teams become more responsive to the health needs of their buildings’ occupants and the surrounding communities.

Read Now

Eighty percent clean electricity generates large benefits

Transitioning to 80% clean electricity would have large benefits on curbing climate change, but also on improving local air quality and health.

Read Now

Biden climate policy would have $1T in heath benefits, save thousands of lives

A clean energy standard would improve air quality and save many lives. Pennsylvania would have the third most health benefits of any state.

Read Now