Many Americans are unaware that cooking can be a significant contributor to indoor air pollution, unless they’ve experienced a mishap like burning food on the stove. However, studies indicate that contaminants released during cooking can lead to health issues such as respiratory illnesses and asthma attacks.
To delve deeper into this issue, I had the opportunity to speak with Brett Singer, PhD, a scientist at Berkeley Lab specializing in indoor air quality research. Recently, he conducted a study measuring pollutant levels emitted from gas cooking burners and ovens in several homes across the Bay Area. During our discussion, I inquired about the findings of this study and sought advice on how to minimize cooking-related pollutants.
Are harmful pollutants emitted when cooking?
A gas burner typically generates notable levels of nitrogen dioxide, a respiratory irritant. Depending on its configuration, it may also emit carbon monoxide, a pollutant regulated by the Environmental Protection Agency (EPA). However, advancements in design have reduced carbon monoxide emissions in newer cooktop burners. Additionally, gas burners produce ultrafine particles, smaller than 100 nanometers, which pose health risks as they can penetrate the body more easily than larger particles.
In contrast, electric burners do not produce carbon monoxide and emit only minimal amounts of nitrogen dioxide. However, electric coil burners may release ultrafine particles, particularly upon initial use.
Regardless of the type of burner, cooking food generates fine particles and various organic chemicals such as acrolein and polynuclear aromatic hydrocarbons, which are hazardous. Cooking methods involving high temperatures, such as frying and broiling, tend to produce higher levels of pollutants.
Fortunately, effective kitchen ventilation can mitigate these pollutants, especially crucial in small living spaces.
What did your in-home study find?
We conducted measurements in moderately sized homes, including eight residences ranging from 1,400 to 2,500 square feet, as well as one small apartment. These homes featured commonly used, well-functioning equipment that had been in use for several years. During our study, we assessed pollutant concentrations in both kitchen and non-kitchen areas while boiling and steaming water on the cooktop and/or oven, with and without ventilation. Alarmingly, we identified issues in half of the homes examined. In four of these homes, the gas-cooking burners emitted sufficient nitrogen dioxide to surpass outdoor air health standards.
What are your tips to minimize these cooking pollutants?
The first tip emphasizes the importance of ventilating during cooking, with increased ventilation corresponding to the intensity of cooking. Range hoods, also known as a stove hood, stand out as the most effective method for ventilation, provided they exhaust air out of the kitchen. In cases where the range hood merely recirculates air back into the kitchen, alternative exhaust options such as bathroom fans or opening windows become necessary.
Consistent usage of hoods or exhaust fans is also crucial. Surveys have revealed that many individuals only sporadically utilize them. Reasons for underutilization include noise, forgetfulness, or the perception that ventilation is only necessary for removing smoke, odors, and moisture, such as when frying pungent foods. However, since pollutants are often imperceptible, ventilation may be needed even when there are no noticeable signs.
When purchasing a new range hood, prioritize selecting a quiet model that suits your preferences. While higher efficiency is desirable, prioritizing user satisfaction and regular usage is key. Additionally, opt for range hoods with higher flow rates that cover the front burners for improved effectiveness.
Furthermore, positioning the range hood over the back burners enhances its performance. Running it at a low speed while cooking on a single back burner can typically capture 50 to 70 percent of pollutants emitted during cooking.
What is the ultimate goal of your research?
Our aim in researching kitchen ventilation is to enable individuals to freely enjoy cooking, whether with gas or electric appliances, without risking exposure to harmful air pollutants. This endeavor aligns with our broader mission of promoting high-performance homes that prioritize energy efficiency and offer healthier living environments for occupants. By offering scientific insights, we aim to educate builders, retrofit contractors, and the public on the importance of proper ventilation in homes.
