Consumer Reports Study Adds to Long Line of Flawed Indoor Air Quality Studies

Recently a Consumer Reports study was published on natural gas stoves’ impacts on indoor air quality,  perpetuating false claims against residential natural gas use. This study isn’t the first time the safety of residential natural gas has been called into question by activists masquerading behind biased research. Activists and their funders started this campaign at the well-head and have quietly moved down the value chain to the household appliances in our kitchens.

As expected from a study of this kind, none of the researchers’ testing revealed dangerous levels of carbon monoxide or particulate matter, nor did oxygen drop to unsafe levels, despite headlines implying otherwise. Researchers ran multiple experiments with and without ventilation, before acknowledging that ventilation did reduce impacts on air quality. While several tests recorded elevated levels of carbon dioxide and nitrogen dioxide, “particularly when the ranges were used without ventilation and a burner set on high,” Consumer Reports draws the overly broad conclusion that residential gas ranges in homes pose health risks.

More of the Same

Consumer Reports’ study is not the first to bury the lede behind an eye-catching headline, only to admit later that the topline doesn’t match up to the findings in the article text. Energy In Depth has unpacked a number of these studies, and despite their headline-grabbing nature, most don’t stand up to inquiry.

In May, researchers with Physicians, Scientists and Engineers for Healthy Energy (PSEHE) published an air quality study and generated coverage in the New York Times, E&E News, and Vox, only to admit in a follow-up webinar the study couldn’t definitively say what the health impacts are because researchers didn’t study exposure.

Consumer Reports’ study – like PSEHE’s – is once again using flawed research to support a campaign interested in banning natural gas appliances.

Indoor air quality commentary and studies have consistently found that emissions from the cooking process — regardless of whether electric or gas appliances are used — represent the chief source of emissions in the home. In an interview with Stanford’s health and medicine blog, the leader of the Lawrence Berkeley National Laboratory’s Indoor Environment Group, Brett Singer, PhD, states:

“Cooking food on either type of burner also produces fine particles and some organic chemicals, including acrolein and polynuclear aromatic hydrocarbons that are known to be hazardous. Frying, broiling and other cooking at high temperatures generally produces more pollutants.

“However, these pollutants can be easily addressed with good kitchen ventilation, which is especially important if you live in a small home.”

Misattributing indoor air pollutants to a certain cooking method rather than a lack of ventilation is a common flaw in indoor air quality studies, particularly those that are conducted with the intent of discouraging natural gas use. One UCLA study commissioned by the  Sierra Club was found to “mischaracterize emissions from gas stoves,” while understating the role of proper ventilation in a cooking environment regardless of the fuel source:

“There are indoor air quality issues associated with the use of gas cooking appliances that will remain despite the implementation of electrification, and we do not account for this. Some PM emissions are associated with cooking oils and foods, and there are no mitigation methods for this, other than the use of ventilation devices such as range hoods. We do not claim that the transition to electric appliances would make a substantial difference in terms of emissions from cooking oils and food.” (emphasis added)

Cooking-related pollutants will be present regardless of what heat method is used and addressing them through proper ventilation in any kitchen environment is crucial. The Consumer Reports study points to guidelines for indoor air quality set by Health Canada, but fails to state that Canada explicitly notes that a range hood exhaust fan can reduce levels of cooking-related pollutants such as PM, NO2, CO and water vapor by 80 percent:

“Running a range hood exhaust on high (300 cubic feet/minute) during cooking can reduce exposure to cooking-related pollutants by more than 80 percent when compared to slower speeds.”

“It is recommended that any range hood exhaust fan fully extend over the stove burners to ensure maximum effectiveness.”

The nod to Health Canada is also seen in RMI’s analysis of gas stoves in its Health and Air Quality Impact and Solutions report. EID scrutinized RMI’s study partially because it fails to distinguish modern gas stoves with electric ignition from gas stoves with a continuous pilot light. The simple truth was that electric ignition stoves emit less NO2, which was confirmed in the Baltimore study cited in RMI’s analysis, in which the scientists documented that homes with a continuous pilot light had higher baseline concentrations of nitrogen dioxide.

The role of proper ventilation is also downplayed by Massachusetts Public Interest Research Group  (MASSPIRG), an affiliate of environmental advocacy network Environment America, in their supporting argument for electrification. However, the study cited by MASSPIRG acknowledged that “use of a vented range hood can dramatically reduce concentrations of pollutants from cooking burners,” with an estimated 55 percent reduction on air toxins.

Activist Backed Studies

The Consumer Reports study is one of a long line of activist activist-backed studies that make dubious claims to crowd out the media space with biased reports. The study was funded by the Climate Imperative Foundation (CIF), a funding organization created by prominent climate movement veterans with a mission to steer big, near-term policy decisions in nations with large carbon emissions.

Thanks to relationships and prior work experience among its executive leadership, CIF has deep connections to other nonprofits that have commissioned or published similar indoor air quality studies, including RMI, Sierra Club, and Environment America. CIF has given numerous grants towards organizations interested in building electrification, including the American Lung Association, Building Decarbonization Coalition, and WE ACT for Environmental Justice. CIF is firmly situated in the “electrify everything” camp and, to that end, pushes claims about how residential natural gas use increases the likelihood of illness or air quality contamination.

Bottom Line: Indoor air quality is an important topic, but it’s important for researchers to disclose the full context of their studies which many of these activist-backed studies fail to do.

Correction: The previous version mistakenly listed Brett Singer’s affiliation as a Stanford University Professor.

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