For decades, scientists and environmentalists have focused on the dangers posed by air pollutants such as carbon monoxide, nitrogen dioxide and particulate matter—tiny particles suspended in the atmosphere.
State and federal regulators have made great strides in reducing levels of such pollutants, at least outdoors. However, researchers from Lawrence Berkeley National Laboratory (LBNL) and elsewhere have been investigating how a common activity—cooking, particularly on gas stoves—exposes millions of Americans to these pollutants indoors, with hard-to-quantify risks.
Earlier this year, a team of researchers from LBNL estimated that, during a standard winter week, 12 million Californians are exposed to indoor nitrogen dioxide levels that surpass state and national air quality standards; for carbon monoxide, the figure is 1.7 million.
The situation is worse in winter, say the researchers, because people keep windows closed, which minimizes ventilation and keeps the pollutants indoors. Ironically, efforts to improve residential energy efficiency in recent decades have worsened the problem, since making homes more airtight also increases the chances that pollutants produced indoors will stay indoors.
The California figures “ballpark-apply across the country,” according to Brett Singer, Ph.D., a staff scientist at LBNL. “Literally, millions to many millions of people are routinely being exposed to air pollutants at levels that we don’t allow outdoors,” he told the journal Environmental Health Perspectives for an article published this month. “The Environmental Protection Agency (EPA) would say we don’t have a carbon monoxide or nitrogen dioxide problem in this country…We absolutely do have that problem. It’s just happening indoors.”
The eye-opening Environmental Health Perspectives article provides an excellent overview of the problem of indoor air pollution and the ongoing efforts to address it. The article reviews the current state of the science of indoor air pollution, with research suggesting that high levels could exacerbate respiratory problems and contribute to loss of lung function.
Part of the difficulty in assessing the scope of the danger is that the amount of pollution created varies tremendously depending on the type of stove, the method of cooking, the temperature, location of the burners and other factors.
The key, say the LBNL scientists, is to design stove range hoods that are far more effective than those currently in use. Most range hoods used now are generally inefficient at capturing the pollutants and transporting them outside, and can generate enough noise to make it difficult to hold a normal conversation.
The researchers say that changes in policy—such as mandating more efficiently designed and quieter range hoods—are the only effective way to address the problem. Consumers can also take certain steps to try to minimize their exposures, including making sure the range hood is turned on, switching it to higher fan settings and using the back burners, since many range hoods don’t actually cover the front ones. The researchers have refrained from advising people not to cook at home—so far, at least.