Cooking worsens air inside
Burning gas stovetop in darkened room. Photo courtesy of D Coetzee/Flickr

Cooking worsens air inside

by Jack Haworth | SDSU student

Key points:
1. Gas and electric stoves give off harmful particulates
2. Without proper ventilation, the pollutants given off from cooking can be harmful
3. Reporter’s experiment shows pollutant levels remain high following cooking experiment

When asked about poor air quality, people often talk about traffic, factories and wildfires, but their own homes could contain some of the worst air.

Scientists at the Lawrence Berkeley National Laboratory in Berkeley, Calif. found the cumulative total of indoor air pollutants is shown to cause serious health concerns.

Gas and electric stoves are big contributors to indoor air problems.

“Gas is a source of nitrogen dioxide which has been shown to be at higher levels in homes with gas stoves,” said Dr. Jenny Quintana, a professor of environmental health at San Diego State. “It can lead to asthmatic symptoms in kids.”

The Berkeley lab reported gas stoves give off nitrogen dioxide, as well as carbon monoxide and formaldehyde, all of which can have health consequences.

The researchers estimate that because of indoor air contaminants, each week 1.7 million Californians are exposed to excessive carbon monoxide levels, 12 million to excessive nitrogen dioxide and 10 million to formaldehyde that exceeded federal standards.

The team at the Berkeley lab also found that while electric stoves do not give off the same harmful gases, they are able to volatize dust and send it into the air as harmful ultrafine particles.

Effects of Cooking on Indoor Air Quality

While stoves themselves can be a major source of poor indoor air quality, cooking on them multiplies the negative effects.

Berkeley lab researchers found that cooking can generate air pollutants including fine particles. These particles, called PM 2.5, can be harmful because they are only 2.5 micrometers in diameter or smaller and can enter the lungs and even the bloodstream.

Tips for using air vents when cooking: Without the use of an air vent, you can be exposed to harmful pollutants. Here are some tips to cut down on air pollution from cooking.

  • 1. Turn on the vents before you start cooking
  • 2. Use the fan on the highest setting
  • 3. Don’t cook with excessive oils and fats that cause heavy smoke when heated
  • 4. Cook food on back burners because the vent will pick up more of the pollutants there
  • 5. If there is no vent, open the windows to improve ventilation.
  • 6. Clean vents regularly

Not only did researchers find that cooking produces PM 2.5, but they also discovered cooking meats and oils produces a  dangerous pollutant called acrolein. It is a chemical that has the ability to damage genetic information within cells, which can lead to mutations and cancer.

“If you are cooking oils at high heats, you get all sorts of weird chemicals formed by combustion,” SDSU’s Quintana said.

Breathing heavy amounts of smoke over time can be especially problematic for chefs who make a living cooking.

“If I’m at work and am subjected to heavy smoke for a long period of time, I’ll often go home with a cough,” said Christine Torres, a professional chef at the Rive Gauche Café in Sherman Oaks. “Sometimes that can last until the next morning when your lungs finally recover.”

Torres explained that usually restaurants have large vents that help get rid of most of the smoke in the kitchen. Unfortunately, most households do not have such effective vents and residents may not even turn them on when cooking.

At-home research

Based on observations from an air quality sensor that this reporter built, the air quality changed while cooking at home. For reference, healthy levels are considered no more than 2,000 PM 2.5. While cooking chicken pasta, the particulate matter was over 8,000 PM 2.5 and stayed elevated for about a half hour after cooking.

Here are some photographs that demonstrate the change in air quality from the beginning to the end of cooking. Keep in mind, when the reporter was not cooking, air quality measurements were approximately 500 PM 2.5.

Cooking Jack Haworth

Photo by Jack Haworth

The pan is warming up. It shows the sensor reading is color teal, which means the measurement is slightly elevated at 1,000-2,000 PM 2.5. 

 

 

Photo by Jack Haworth

Photo by Jack Haworth

 

 

 

 

Two minutes into the cooking. Clearly the sensor reading is displaying a light orange color, which indicates the measurement has risen to 2,000-3,000 PM 2.5.

Photo by Jack Haworth

Photo by Jack Haworth

 

 

 

 

Ten minutes into the cooking process. The sensor reading changed to the color purple, which means the reading has risen significantly to above 7,000 PM 2.5.

Photo by Jack Haworth

Photo by Jack Haworth

 

 

 

Approximately 20 minutes after the cooking had finished. The sensor reading was a dark orange color which meant the reading was still elevated to 4,000-5,000 PM 2.5.

 

 

 

Numbers in this story represent the raw mass concentration of particulate matter in the air at the 2.5 level or smaller at the time of observation and may not be completely representative of PM2.5 values without the conversion calculation that is required.

This test demonstrated that at least some cooking spikes air pollutants. Worth noting is that the levels stayed elevated for approximately 30 minutes after cooking.

Kevin Robinson, lecturer at  SDSU’s Department of Geological Sciences, explained reasons the air particles stay suspended in the air.

“The particles would stay in the air longer if they are super lightweight or if there is any convection or heat keeping them up in the air,” Robinson said.

As long as the temperature of the kitchen is elevated from cooking, the particles stay suspended in for extended periods of time.

“Sometimes I’ll be cooking and forget to turn the (vent) fan on, then before I know it, the whole house will get smoky,” said SDSU student Connor Wilcox.

This is a problem many college students face while living with roommates.

“I live in a loft above the kitchen and when my roommates are cooking, the smoke goes up into my room and sometimes it is so bad it gives me a headache,” said UCSD student Haley Asturias.

“Ventilation is one of the biggest factors to improving air quality while cooking,” said Robinson.

Click here for more from “What’s in the Air”

Jack Haworth was enrolled in San Diego State’s “What’s in the Air” sensor journalism class in Spring 2015.

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