Cooking and Indoor Air Pollution: How Your Air Quality is Affected

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Written By Jamila W.

The World Health Organization has identified cooking as one of the biggest contributors to household air pollution. Particulate and gaseous air pollutants generated by grilling, roasting, frying, broiling, and boiling is a global public health issue that claims millions of lives each year. And while open fires and inefficient stoves are not common issues in developed countries, the deterioration in air quality associated with cooking can cause health problems like stroke, COPD, and lung cancer. In this article, we explain the relationship between cooking and indoor air pollution, and the steps you can take to prevent your air quality from being affected. 

The Science of Cooking and Air Pollution

If you’ve ever pulled a smoking brisket out of the oven, scorched your toast, or carbonized your scrambled eggs, you and your smoke alarm know just how much air pollution cooking can generate. In many ways, the kitchen is more like a laboratory or industrial facility than a domestic environment, with the high cooking temperature driving the release of cooking indoor air pollution. Various cooking processes create chemical reactions with airborne pollutants as the byproduct. 

Chemical Reactions Involved in Cooking

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Air pollution in the kitchen doesn’t only come from burning food. The air pollution generated by cooking can be attributed to several key chemical reactions that take place as your food is prepared including:

The Maillard reaction, is an organic chemical reaction that takes place when you heat proteins and carbohydrates together. It generates several noxious volatile organic compounds (VOCs), including acrolein,  polycyclic aromatic hydrocarbons, and formaldehyde.

The direct combustion of fats and oils is known to generate significant quantities of particulate matter (PM), which is associated with respiratory problems like asthma.

The direct combustion of fuel in stoves and gas ovens generates carbon monoxide (CO), formaldehyde, and nitrogen dioxide, with wood stoves producing smoke. The inefficient combustion of solid fuel increases the generation of fine particles and poisonous carbon monoxide.

The ‘burn-off’ of food waste on heating filaments in electric ovens generates high levels of particulates as burned on food and fat is carbonized. The self-cleaning setting on electric ovens also generates high levels of pollutants because of this effect.  [1]

Types of Pollutants Emitted During Cooking

Cooking exposes kitchen occupants to three of the six primary outdoor pollutants monitored by the  Environmental Protection Agency national ambient air quality standards (NAAQS) mandated by the Clean Air Act. Carbon monoxide, nitrogen dioxide, and particulate matter are just as common in the kitchen as on a busy roadway at rush hour.  Nitrogen dioxide is produced when natural gas is burned on a gas stove, while CO is produced when any fuel source is burned without sufficient oxygen.

These pollutants can have serious health effects, including respiratory problems, headaches, and nausea. Long-term exposure to high levels of these pollutants can also increase the risk of heart disease and other chronic health conditions.

Other air pollutants produced by cooking include:

  • VOCs
  • Polycyclic aromatic hydrocarbons (PAHs)
  • Chloramines 
  • Brown carbon
  • High temps and humidity
  • Nitryl chloride [2]
  • Acrylamide

Factors Influencing the Level of Pollution Generated by Cooking

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As you can see, cooking can significantly affect the air quality in your home, and several factors can influence the level of pollution. Understanding these factors can help you take steps to reduce indoor air pollution and improve the air quality in your home.

Cooking Methods Massively Impact Indoor Air Quality

The cooking methods you use can have a significant impact on indoor air pollution. The cooking activities that generate the most harmful levels and types of indoor air pollution include:

Browning meat: Sadly the aromatic smells that are released by browning meat are brown carbon and VOCs and nitrogen dioxide. Browning also generates high levels of particulates because of incomplete combustion.

Grilling: Barbecue fumes from grilling generates major air pollutants like fine and ultra-fine particulates, and black and brown carbon, with studies demonstrating an association with short-term respiratory tract inflammation and irritation

Deep frying: Cooking foods in oils or fats at high temperatures in deep fryers generates dangerous levels of polycyclic aromatic hydrocarbons (PAHs) and particulate matter. Stir-frying has similar effects.

Using cleaning chemicals while cooking:  Using chemicals like bleach near a natural gas burner can induce chemical reactions that produce noxious volatiles like chloramines, which are known respiratory irritants. 

In addition, the type of food that is prepared has a significant impact on the type and quantity of pollutants released. For example, meat with a high-fat content generates the most particulate matter as it cooks, and spices have unique atmospheric chemistry and may even improve air quality if they are included in particular dishes.

Ventilation in your kitchen

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Ventilation is a critical factor for a safe indoor environment when cooking and one of the most important areas to address to improve air quality in kitchens. Having suitable mechanical and passive ventilation dilutes and reduces harmful pollutants, circulates cleaner outdoor air, and helps to improve air quality. In lesser economically developed countries, the lack of ventilation in indoor cooking spaces, and inefficient fuel and natural gas stoves, lead to a build-up of harmful pollutants that have a disproportionate effect on the health of women and children. 

The Duration and Frequency of Cooking

Air quality in kitchens and the wider home environment will deteriorate with prolonged periods of cooking or frequent episodes of frying, grilling, and broiling throughout the day. The more you cook, the greater your exposure to these common pollutants. Changing your patterns of cooking and using methods like boiling or steaming that generate fewer pollutants can help. 

Open plan living 

Exposure to pollutants from cooking is higher in homes where the kitchen is part of an open-plan living space. In these environments, pollutants simply build up in the living or dining room, especially if mechanical ventilation is limited. Not only is there the issue of humidity and breathing comfort, occupants may have to put up with persistent odors, that penetrate the interior decor of the room.

Humidity and Temperature

Other factors that affect indoor air quality related to cooking are the rises in humidity and temperature that come with preparing food. Boiling water without a lid on the pot will add large amounts of moisture to a kitchen, and affect breathing comfort. Raised temperatures and high humidity lead to air stagnancy causing air pollutants to persist in indoor air and your exposure to them to be prolonged.

The Health Effects of Poor Indoor Air Quality from Cooking

Cooking has an immediate and significant impact on the air quality inside your home. Even with competent mechanical ventilation, the smoke, fumes, and particulate matter released during cooking can cause immediate and long-term health effects on your health. The release of air pollutants from cooking, especially where solid fuel like wood, or gas stoves are used, makes it a significant contributor to household air pollution, a leading risk factor for premature death

Immediate Effects of Poor IAQ from Cooking 

Indoor air pollution levels in a kitchen start to increase from the moment you ignite your natural gas stove or switch on the oven. Cooking with a gas stove can release carbon monoxide, and solid fuels like wood release particulates that are difficult to avoid inhaling. As explained above, the chemical reactions that take place inside food as it cooks release air pollutants that affect anyone within the kitchen environment. Of course, the person preparing the food has the highest exposure. 

Symptoms caused by the smoke and fumes released during cooking include:

  • Eye irritation
  • Upper respiratory tract inflammation and irritation
  • Coughing and wheeze
  • Headaches 
  • Nausea
  • Dizziness
  • Fatigue
  • Exacerbation of existing respiratory diseases like asthma or Chronic Obstructive Pulmonary Disease

Long-Term Effects of Indoor Air Pollution from Cooking

The longer-term effects of prolonged exposure to airborne pollutants from cooking have the most pervasive health consequences. According to the World Health Organization, there are over 3.2 million deaths annually that are related to indoor air pollution. This includes more than 237,000 infant and child deaths, mainly from asthma and respiratory infections.

The morbidity and mortality from cooking-related air pollution are particularly related to the release of fine particulate matter (PM2.5) during cooking. Fine and ultra-fine particulates penetrate the deep tissues of the respiratory system where they cause ongoing irritation and inflammation. Over time they also cause immune system changes that make exposed individuals susceptible to lung disease and lung cancer. 

Other notable health consequences of cooking related-air pollution include:

  • Ischaemic Heart Disease
  • Stroke
  • Cataract
  • Lower respiratory tract infections like pneumonia and tuberculosis
  • Hypersensitivity pneumonitis 
  • Chronic obstructive pulmonary disease (COPD)
  • Nasopharyngeal and laryngeal cancers

Cooking with gas stoves also increases the risk of chronic respiratory problems. A study found that children who lived in homes with gas stoves had a higher risk of asthma and wheezing.[3] The household air pollution created by cooking has also been associated with the particular risk of pediatric health problems that include, low birth weight, and developmental delays. This is because young children spend more time indoors.

These serious health consequences make it essential to protect your household from the effects of indoor air pollution from cooking, particularly by ensuring you proper ventilation and air purification in your kitchen. 

Recommendations for Improving Cooking-Related Air Quality

The health risks of air pollution generated by cooking are difficult to escape because people cook their meals every day. Recognizing that indoor air pollution from cooking is a problem is the first step to protecting yourself, and your family from its pernicious effects. Strategies for reducing air pollution exposure from cooking include:

Use Cleaner Cooking Methods

Cleaner cooking methods enable you to prepare food without releasing copious particulates and VOCs. In many cases, avoiding frying, grilling, and roasting may be healthier too. Here are some examples of cooking methods that reduce cooking pollution:

  • Avoid using deep fryers or shallow frying food as it releases a lot of smoke and vapors that can pollute the air.
  • Use a lid on pots and pans to prevent smoke and steam from escaping and polluting the air.
  • If you want to grill, do it outside on an electric or gas outdoor grill.
  • Opt for electric or induction electric stoves instead of gas stoves as they produce fewer emissions.
  • Use non-toxic cookware made of stainless steel, cast iron, or ceramic to avoid releasing harmful chemicals into the air.

Boost Ventilation

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In developed countries, most properties have access to some form of kitchen ventilation. Modern building regulations also make it essential to install mechanical ventilation in kitchens of new-build, or renovated homes. However, enhancing any existing ventilation you have will be the best way to reduce indoor pollution caused by cooking. Here are some ways to improve ventilation in your kitchen:

  • Install a residential kitchen exhaust system that vents outside to remove smoke and cooking fumes from the air. In new building and home renovations, this is encouraged by building codes, though it is not a legal obligation. 
  • Open windows or doors to let in outdoor air and improve airflow while food is being prepared. Opening multiple windows and doors in different areas of the kitchen will improve air quality and dilute indoor pollutants with fresh air. 
  • Use a kitchen hood or range hood that is vented outdoors to remove smoke and cooking fumes from the air.
  • Prevent CO poisoning by having the venting of gas stoves and gas ovens checked by a suitably qualified HVAC professional or member of the American Gas Association to ensure that harmful exhaust gases are being removed from the kitchen. New gas stoves and other gas appliances should be properly installed by a contractor.
  • If you cook beneath range hoods, use the back burners of your stove, so that pollutants released will be more effectively captured by the hood as they ventilate the back of a stove most effectively.[4] 

Using Air Purifiers

Air purifiers are another solution for removing cooking pollutants from the air and improving kitchen air quality. These portable devices, use a range of technologies to trap, retain, or destroy the pollutants released while you cook. Air purifiers can be run for a prolonged period after cooking to strip the air of lingering particulates and odors.

Because of the frequency of cooking and heavy particle load, the specifications of the air purifier will be important:

  • Look for an air purifier with a HEPA filter. This high-efficiency mechanical filtration removes particulate air pollutants as small as 0.3 microns with 99.97% efficiency. It is the ideal solution for removing smoke, cooking fumes, and other pollutants from the air.
  • Choose an air purifier with a high CADR (Clean Air Delivery Rate). This is the volume of cleaned air in cubic feet that the air purifier releases each minute. A high CADR ensures that your choice of air purifier can clean and recirculate the air in your kitchen efficiently and effectively.
  • Opt for a portable air purifier that you can place near the cooking area to capture pollutants before they diffuse throughout your home.

In Conclusion

By adopting cleaner cooking methods, improving ventilation, and using air purifiers, you can reduce indoor pollution and improve the air quality in your home. To minimize the impact of cooking on your indoor air quality, it’s important to ensure that your kitchen is well-ventilated. This can be achieved by opening windows, using exhaust fans, or installing a range hood. Additionally, using cleaner cooking methods, such as baking or steaming instead of frying, can also help reduce the amount of pollutants produced during cooking.