Hesperian Health Guides
Cooking Fires and Smoke
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Most women spend many hours a day preparing food. This puts them at risk for health problems caused by cooking fires and smoke.
Kerosene and other liquid and gas fuels can cause explosions, fires, and burns. To use these fuels more safely:
- do not let the fuel touch your skin or drip anywhere. If it does, wash it off right away.
- keep anything that can burn away from the stove. This will prevent fires from spreading and causing great damage. Store extra fuel in a safe place away from where you cook (and do not use matches or cigarettes nearby).
- put the stove where air can move freely around it.
- always be careful when lighting the stove.
Small children who spend much of their day playing near a smoking cookstove are at greater risk for colds, coughs, pneumonia, and lung infections.
Women are at greater risk for these health problems than men, because women spend more time breathing smoky air.
Women who cook with fuels that produce a lot of smoke — such as wood, coal, animal dung, or crop remains — often have health problems. These fuels cause more problems when they are burned indoors where the smoke does not move out quickly. And if the fuel has chemicals in it — such as pesticides or fertilizers in the crop remains — the smoke is even more harmful.
Breathing smoke from cooking fires can cause chronic coughs, colds, pneumonia, bronchitis, lung infections, and lung disease. Breathing coal smoke can also cause cancer in the lungs, mouth, and throat.
Pregnant women who breathe cooking smoke can suffer from dizziness, weakness, nausea, and headaches. And because a woman’s body is less able to fight infection when she is pregnant, she is even more likely to get the lung problems mentioned above. Smoke can also make her baby grow more slowly, weigh less at birth, or be born too early.
Preventing health problems from smoke
To reduce the amount of smoky air you breathe:
Cook where air can move freely. If you cannot cook outdoors, then make sure there are at least 2 openings for air in the room. This creates a draft, so the smoke will leave the room.
Cook in turns with other women. This way each woman will breathe less smoke.
Find ways to prepare food that require less cooking time (but still cook foods completely). This way you will breathe in less smoke, and you will also use less fuel. Food cooks more quickly and completely if you:
of rock, clay, or iron sheets can
help keep heat around the pot.
overnight before cooking.
wood from rain.
Smoke is a sign that fuel is being wasted, since it is caused by fuel that does not burn completely. Finding ways to cook with less smoke can save money as well.
Use stoves that produce less smoke. This is the best way to prevent health problems caused by cooking smoke. Stoves that burn less fuel and produce very little smoke may be available in your area, but they can also be made easily with local materials. See below for instructions.
Stoves burn less fuel and produce less smoke when they have:
- protective lining (insulation) between the fire and the outside of the stove. Materials that trap a lot of air — like ash, pumice rock, dead coral, or aluminum foil — keep heat inside, instead of escaping out of the sides of the stove. This keeps the fuel burning hotly, which reduces smoke. Avoid using clay, heavy rock, sand, cement, and brick to prevent heat escaping from your stove because they do not trap enough air.
- chimneys inside the stove (see below) that help the air move around the fire. A longer chimney outside can also help cut down the smoke in the cooking area.
- 'skirts' (material around the cooking pot) to reflect the heat coming out of the chimney and direct it back to the pot. The pot then absorbs heat from all sides.
- a small burning chamber (see below) that allows you to burn one end of a piece of fuel in the chamber while the rest of the fuel stays outside. As the part inside burns, you can push the fuel further in.
How to make a stove and cooker that reduce smoke
The rocket stove
This is one example of a stove that is easy to make. You may need to adapt it for the fuel you use and the materials available in your area.
You will need:
- a large (5 gallon) can, such as a cooking oil can, soy sauce can, large paint can (well-cleaned), or a can that medical supplies were packed in. This will be the body of the stove. Cinderblocks or bricks may also be used, but a large can is better because it is thin and does not absorb as much heat.
- a 4-inch wide metal stove pipe with a 90-degree bend (elbow) in it. The pipe on one side of the elbow should be longer than the pipe on the other side. You will also need a straight stove pipe to attach to the short end of the elbow.These pipes will be used to create the burning chamber and chimney for your stove. (4 or 5 tin cans with their tops and bottoms cut out can be used instead of stove pipes.)
- insulation such as wood ash, pumice rock, vermiculite, dead coral, or aluminum foil.
- tin snips and a can opener for cutting the metal.
- extra metal for creating a ‘skirt’ around the pot.
- grating or thick fencing for the top of the stove, where the pot rests for cooking.
How to make the stove:
- Use the can opener or tin snips to take the lid off the big can. Cut a 4-inch round hole in the middle of the lid for the chimney. Cut another 4-inch round hole in the lower front side of the can, about 1 inch up from the bottom of the can, for the burning chamber. The holes you cut should fit around your stove pipe or tin cans.
Place the stove pipe with the elbow inside the can so that one end sticks out of the front of the can. Make 2 parallel cuts ½ inch apart at the long end of the pipe and bend the section back to create a lip. This way the pipe will not slip back into the can. The long section of this pipe will be the burning chamber (where the fuel burns). Attach a straight section of pipe to the short end of the elbow to make a chimney that ends 1 inch below the top of the can. Make a lip on this pipe, too, so the top of the pipe will not fall into the can.
Note: A chimney made from tin cans will only last 1 to 3 months, and then you will need to replace it. To prevent this, try making a fired clay chimney with a mixture of 3 parts sand and 2 parts clay. Put this clay around the chimney of tin cans. When the cans burn through, you will have a clay chimney supported by all the insulation packed around it.
- Fill the body of the stove, around the chimney, with insulation such as wood ash.
- Replace the can lid over the insulation and around the chimney.
- Use a tin can to make a shelf inside the burning chamber. Remove the ends of the can and flatten it. Then cut it into a T shape that will fit inside the pipe. The top of the T will stick out and keep the shelf from slipping inside. Place a brick or rock under the outside part of the shelf to support the twigs while they are burning.
- Use your grating or fencing for resting the pot on the top of the stove.
- Make a skirt with extra metal. It should surround the pot, leaving a ¼ inch gap between the skirt and the pot at its base. For an even better skirt, make a double skirt and put insulation between the 2 sheets of metal.
|If you need to cook inside, place the stove near a wall with an opening in it. The smoke can climb along the wall and leave the building.|
The haybox cooker
|Keep the hay cooker away|
from an open flame.
To save even more fuel, use a haybox cooker to keep food warm or to simmer it after it has come to a boil on your stove. This cooker can cut fuel use by more than half when cooking beans, meat, rice, or grains. Rice and grains will use ⅓ less water, because not as much water will evaporate.
Make a haybox by lining a cardboard box with 4 inches of hay (or use straw, sawdust, old clothing, feathers, chaff, cotton, wool, styrofoam, or corrugated cardboard). Leave space inside the box for your cooking pot and for more insulation on top of the pot. The lid of the box should fit tightly.
When using the haybox cooker, remember:
- food cooked in the haybox takes 1½ to 3 times longer to cook than over a fire.
- beans and meat should be simmered on your stove for 15 to 30 minutes before going into the haybox. The foods may need to be reheated after 2 to 4 hours.
- keep the pot closed and boil meat dishes again before eating. This prevents bacteria from infecting your food.
For more information on stove and oven designs, including easy-to-build solar stoves, contact Aprovecho Research Center.