Beware of poisonous gases given out during cooking.
Posted on November 25th, 2012

Dr Hector Perera            London

Carbon monoxide (CO) is an odourless, colourless gas often formed in the process of incomplete combustion of organic substances, including fuels. CO is a gas that can build up to dangerous concentrations indoors when fuel- burning devices are not properly vented, operated, or maintained. Because it has no odour, colour or taste, CO cannot be detected by our senses such as smell. It is estimated that unintentional CO exposure accounts for an estimated 500 deaths in the United States each year. There are approximately 400 admissions to hospital with Carbon Monoxide (CO) poisoning in England each year and around 40-50 deaths. In developing countries biomass combustion is a frequently used source of domestic energy and may cause indoor air pollution. The smouldering burn of incense or cigarettes also produces carbon monoxide. Most Asians burn incense sticks or powder inside the homes, hopefully they ventilate the place afterwards to get rid of carbon monoxide gas.

In cold weather countries the most serious effects of carbon monoxide in the home occur in the winter, when homes are closed up more tightly.  Some energy saving experts advice to close doors and windows to prevent losing heat to save energy but you need to think twice when to ventilate. Who would cook in the kitchen without ventilation? Remember to ventilate the kitchen in rain or shine. In some British and American TV cooking shows, the chefs hardly talk about some scientific factors such as carbon monoxide and carbon dioxide build up inside the kitchens while cooking on gas cookers. Quite often the gas rings are on full blast while cooking or sometimes idling that is a total wastage of cooking gas. At home it is very important to ventilate the kitchen while cooking that does not mean to leave all the windows open but need to let some air come into the kitchen while cooking. Remember oxygen in the air is burnt by methane or cooking gas and produce carbon dioxide and some monoxide. If there were lack of ventilation these poisonous gases build up in the kitchen and the people in the kitchen have to inhale the poisonous gases. Just not carbon monoxide but in high temperature even the unreactive nitrogen also combines with oxygen to produce oxides of nitrogen. The oxides of nitrogen with further arial oxidation produce another oxide of nitrogen which is water soluble to form nitric and nitrous acid. Wouldn’t it possible it would dissolve in our breath to produce this acid. Normally this reaction gives acid rain. This reaction also happens in motor vehicles. Hundreds of Americans die every year from carbon monoxide poisoning caused by improperly used or malfunctioning fuel-burning appliances.

 Wok cooking

The aroma of seared meat as your pan-fried steak is prepared may set your taste buds tingling “”…” but it may also give the chef cancer, especially if they are using a gas cooker. Cooking fumes produced during high-temperature frying are already known to cause cancer. In China, high lung cancer rates among chefs have been linked to the practice of tossing food in a wok, often in a confined space, which increases the concentration of hot oil in the breathing zone of the cook. The International Agency for Research on Cancer has also classified cooking fumes as “probably carcinogenic”. Now researchers from the Norwegian University of Science and Technology in Trondheim have compared gas and electric cooking methods, and found that gas produces higher levels of the cancer-causing fumes.

Firewood stoves

In some parts of Sri Lanka some people still use firewood for cooking. In the past many people including at our homes as well, used nothing but firewood stoves now gradually changing and some of them use gas cookers and electric cookers. How would they use firewood stoves in apartment blocks? That is why the style of cooking has changed.

When we cook by firewood, we always get smoke; we cannot get smokeless flame with firewood unlike in gas cooking. Black smoke is due to incomplete combustion of organic matter such as, wood or even coal. In a typical firewood kitchen in Sri Lanka, it’s not uncommon to have a kerosene lamp as well that always gives a stream of soot or carbon black, often gives some fumes of kerosene as well due to incomplete combustion of fuels. If the firewood fails to light up, a quick dash of kerosene from the lamp is a solution but it’s quite dangerous because the whole thing might catch fire. How often this small lamp spills near the stove and catches fire?  A few similar incidents happened in England when people throw BBQ lighting sprit into the fire but our servants in Sri Lanka were experts in doing these acts.

Burning fire wood fire is a type of chemical reaction, in which wood reacts with oxygen, so that if it is burning well, there are other gaseous products other than carbon dioxide (CO2), water (H2O) and a small amount of ash, which cannot burn any further.

Suffering and cocktail of gases

In a kitchen they burn so many kinds of firewood, such as coconut leaves, husks, shells, cinnamon, cashew, rubber or any kind of dry wood and we burn or chemically we call, oxidized. Sometimes biomass fuels or fossil fuels, the main by-products are the same, heat, smoke, carbon dioxide and monoxide and oxides of nitrogen. When food is cooked inside the homes with firewood, dung, coal or with other solid fuels, it creates high level of indoor air pollution. Say for example a mixture of different firewood such as rubber, cashew or coconut leaves and shells are burned in cooking rice, curries and frying dry fish in open fires; it gives a cocktail of nasty smelling gases including smoke. They say, “No smoke without fire” but it smokes before it catches fire then, fire and smoke come out. If it didn’t catch fire, some people use some kerosene from the kerosene lamp or blow several times into the fire.  Just imagine the heat on the face, eyes and the hair. How would these kitchen servants stop inhaling these gases, while trying to light fire because they are so near the stove? Sometimes they cough several times continuously, tears and nose drooling, sneeze then need to blow out the wet and blocked nose several times to unblock the nose while sweating. I know it because I also have cooked in open fires to see the actual situation? I must say, it’s not a pleasant experience, I have a practical experience. You smell like a smoked mackerel, haddock or bacon or dry fish or “Jardi” when sweat mixed with, dust and ash on hair, face and on clothes, black soot on hands and on clothes, looks like wearing a mask, too much to describe. I am wondering how some of these servants and some people undergo this suffering every single day, many hours in the open fire kitchens? It is still happening in Sri Lanka because of the energy poverty. 

Kitchen windows always open

One thing for sure in Sri Lanka because of hot weather climatic conditions, they always cook with open windows so there wouldn’t be any build up of poisonous gases in the kitchens. On the other hand in cold weather countries it is possible most of the times a majority of people cook without due care of ventilation. Sure there is extractor fan set to work but must get outside fresh air while cooking.

 If there are small children are around in the house, you need to be careful about the gas cooker because some might turn the gas knobs on without realizing the dangers. After cooking it is always advisable to check the gas cooker and turn off the gas especially in the night. Some people forget to check the oven and leave it while still baking. Sometimes they might turn the grill on by accident either fire on or just turned it on with gas building up. If the cooker top is uncleaned, the oil and spillages would catch fire, so always keep the cooker clean. How about a junk food takeaway so no cooking problems? Any comments please [email protected]

One Response to “Beware of poisonous gases given out during cooking.”

  1. HussainFahmy Says:

    A valuable piece of advice neglected specially in the Middle East countries where the windows are kept locked due to severe weather conditions. A sensible lifestyle should be the objective to a healthier and safer living. Thank you Dr Hector Perera.

Leave a Reply

You must be logged in to post a comment.

 

 


Copyright © 2018 LankaWeb.com. All Rights Reserved. Powered by Wordpress