Every morning, when millions of Americans turn on the gas stove to boil water or prepare something to eat, they are not only spreading a pleasant smell around the house: the blue flame also emits harmful pollutants such as nitrogen dioxide, in addition to harmful gases to the planet.
For this reason, a team of scientists from Stanford University recently began a marathon of tests across several apartments in New York, with the aim of better understanding the extent of this type of pollution and how it spreads between rooms. The initiative is part of a study in ten cities that already shows how contaminating agents can quickly reach the living room and bedrooms, sometimes going far beyond the appliance that generated them.
Concern about the effects on health and the climate has already led some US cities and states to consider phasing out natural gas distribution facilities from buildings, and the federal government also wants to enforce stove efficiency standards, but the issue is controversial. Last week in Washington, Republicans convened a House of Representatives Oversight and Accountability Committee hearing to “review the Biden administration’s regulatory assault on the nation’s gas stoves.”
On a clear Sunday morning, the Stanford scientists made their first stop at a housing project in Morningside Heights, in Upper Manhattan. The first challenge: carrying more than 135 kilos of equipment to the 18th floor. “I just hope there’s an elevator,” muttered fearfully Rob Jackson, a professor at the Doerr College of Sustainability and team leader. (He had.)
The three-bedroom apartment they were going to visit — where Tina Johnson lives, with three grown children — overlooks an elevated railway and has a kitchen with a table, perfumed with the aromas of the herbs and spices she uses to prepare her favorite recipe, a braised in the French ratatouille style. In fact, she had just cooked fried eggs and potatoes for breakfast.
“I’m glad you came. They just installed the new stove, but I can’t stand the smell of gas. Both my children and I have asthma and other health problems. I’m curious to know what it does to the air we breathe,” she said. the resident, who volunteered to participate in the study through a local climate advocacy group.
Assessing the losses
The researchers started the work by activating the analyzers and installing tubes at nose height to take air samples. After reading the environment, it was time to turn on the gas, turning on one of the small burners on high heat.
It didn’t take long for the machine to detect the change: an increase in the concentration of nitrogen dioxide (NOtwo), which, among other harmful effects, can irritate the respiratory system, aggravate the symptoms of respiratory diseases and contribute to the development of asthma. The volume rose to 500 parts per billion, five times higher than the safe limit for one hour of exposure set by the Environmental Protection Agency (EPA, in English). The concentration of benzene, a human carcinogen also present in cigarettes and car emissions, has tripled.
This was with the door and window closed; and the kitchen does not have a hood, which would help with ventilation. By opening both, as Johnson says he does every time he cooks, the NO leveltwo it dropped to 200 parts per billion, but with that the fumes spread to the rest of the apartment. In one quarter it reached 70 parts per billion, below the EPA limit but far above the World Health Organization recommended standard for continuous exposure.
There is a growing body of scientific evidence of the health hazards caused by gas stoves. An article published late last year concluded that the appliance may be linked to nearly 13 percent of childhood asthma cases in the US. Previous research reveals that it also leads to worsening symptoms of the disease.
On the other hand, it is possible to take some simple measures to reduce the danger, such as opening the windows and buying an air purifier.
The next day, the team resumed measurements at another location, this time at an Airbnb in central Harlem. According to Yannai Kashtan, a doctoral candidate in Earth system science and a member of the group, the intention was to recreate the atmosphere of a large family or a party.
To limit their own exposure, the members clustered on the balcony overlooking Upper Manhattan, holding their breath and rushing inside to check the levels. In a period of 40 minutes, the level of nitrogen dioxide hit 200 parts per billion in the living room, 300 parts per billion in the bedroom and 400 parts per billion in the kitchen, that is, double, triple and quadruple, respectively, limits established by the EPA for exposure up to one hour. The benzene concentration also tripled after the stove was turned on.
This time, there was a hood. “But that’s all it feels. It’s not making much difference,” Kashtan said, his hand in the hot air stream blown out of the rig’s outlet instead of out.
In total, the team ran tests — lasting a whole day — on eight homes in New York, including a house in Brooklyn where the researchers were stunned to find a detail peculiar to the city: windows sealed with plastic. According to Nina Domingo, who lives on the ground floor with two other people, the measure reinforces the insulation – but also means poor ventilation, which is dangerous, as the kitchen also does not have a hood to take the gases out. In the area closest to the room, the concentration of NOtwo it didn’t take long to reach a value two and a half times higher than the EPA recommended.
The results are preliminary, but are in line with scientific research linking stove emissions to pollution that affects both climate change and public health. Previous studies have also shown that the gases continue to spread even with the device turned off, because natural gas, usually methane, which is a strong greenhouse element, can leak.
But changes may be close: more than 60% of US homes already use electricity to prepare meals, and the Biden administration has proposed an expansion of gas stove efficiency rules, which would represent an estimated energy savings of US $100 million plus climate and health benefits. Several cities, mostly in states governed by Democrats, have banned or are considering banning gas installations in new buildings, thereby requiring the use of electricity in cooking and heating, although Republican states are already moving to reject the measure.