A new study finds that even people with an average sense of smell could be living with a natural gas leak without knowing it. This research highlights the impact of small gas leaks on indoor air quality, introducing various hazardous air pollutants, including benzene, a carcinogen found in 97% of natural gas samples across North America .
Small gas leaks, although not sufficient to cause explosions, are common and difficult to detect.
“The fact that they are so small makes them difficult to identify and repair, which can lead to a persistent Source of benzene and methane inside,» explains Sebastian Rowland, lead author and scientist at PSE Healthy Energy.
This study is the first to evaluate whether gas leaks contain enough of the odorant to protect against high levels of benzene exposure. Researchers collected and analyzed 587 natural gas samples from 481 residences in 17 North American cities. The samples were tested for methane, hazardous air pollutants and sulfur-based odorants.
Alarming results
The results confirm the presence of benzene and other hazardous air pollutants in almost all natural gas supplied to homes, buildings and businesses in North America.
“Our nose is the first and only line of defense against domestic gas leaks,» emphasizes Drew Michanowicz, principal scientist at PSE. “Given the variation in odorant levels and the enormous disparity in the ability to smell among the general public, our results call into question the exclusive reliance on smell to protect people from gas leaks..”
On average, gas delivered to homes in Vancouver, Los Angeles, Calgary and Denver contained levels of benzene twice as high as in other cities, with levels in Vancouver almost fifty times higher than those in Boston, the city with the lower concentration. Odorant levels in Houston’s gas were about five times higher than those in Toronto, while neighboring New York and Washington, D.C., appeared to use different odorants, indicating a lack of standardization.
Recommendations for better security
The researchers suggest that regulators and consumers would benefit from greater transparency about the composition of natural gas, such as open access to natural gas composition data and regular sampling.
Improving leak detection through stricter odorization standards or increased use of leak detection devices, or reducing gas use, could improve indoor air quality and public health.
Illustration caption: PSE Healthy Energy researchers take samples of unburned natural gas on a stove. Credit: Alessandro Citterio
Article: “Downstream natural gas composition across US and Canada: implications for indoor methane leaks and hazardous air pollutant exposures” – DOI: 10.1088/1748-9326/ad416c
