What are indoor “pollutants”?
With homes being built more airtight and better insulated than ever before, ventilation is receiving lots of attention these days. It’s becoming common knowledge that modern buildings need mechanical ventilation, such as exhaust fans or heat recovery ventilators (HRVs), to flush out pollutants and provide fresh air to occupants. But sometimes we skip the part where we actually define these “pollutants” so people can know what’s in their house and understand the true value of ventilation.
Pollutants can be introduced into a home in many ways – humans breathe out carbon dioxide, heating appliances can produce carbon monoxide, radon can leak in through the foundation, and dust can blow in through a door or window. Pollutants are also produced in kitchens, one reason for installing range hoods above stoves.
What pollutants are produced in kitchens?
Cooking creates both moisture and odors, both of which can be good in small doses – water vapor helps maintain higher indoor humidity during dry winters and smells can entice family members to dinner–but damaging in excess.
Gas burners release gases directly into a home, which can reach harmful levels if not exhausted. Nitrogen dioxide, which can cause respiratory problems, is one by-product of gas combustion. Carbon monoxide is another, a colorless, odorless gas that reduces oxygen delivery to organs and can be fatal to humans at high enough concentration. If you have a gas burner, it’s a good idea to have a carbon monoxide detector in your kitchen, in addition to ventilation.
Cooking appliances also produce small airborne particles like PM 2.5 that can enter lungs and cause respiratory problems. An extreme example of this (and one you can smell) is when you turn on a heating appliance that has been dormant for awhile, like a toaster you haven’t used in months. Finally, certain cooking methods and foods produce harmful pollutants like acrolein, which many recognize as the acrid smell of burnt fats like cooking oil.
What is effective kitchen ventilation?
It depends on the amount and type of cooking you do. Boiling water for pasta once in awhile will not produce as many pollutants as pan frying steaks in a busy restaurant. Of course, most homes fall between these two extremes. Consider your cooking habits when choosing a ventilation strategy.
Range hoods are your best option for kitchen ventilation and come as stand-alone systems or can be integrated into other kitchen appliances, such as microwaves. They should be turned on every time you cook. Range hoods can vary in performance, so it is important to ensure your system provides sufficient ventilation for the type of cooking you do. Also, range hoods must actually exhaust air outside a home rather than just circulate air through a grease trap. Ideally the range hood should also extend over all burners of the stove. In the summer, opening a window can also help with ventilation.
Whole house ventilation systems such as HRVs help provide adequate ventilation while cooking, as it’s common for range hoods to capture only a fraction of the pollutants released. One option is to use the HRV’s boost mode while cooking. If you do use an HRV for kitchen ventilation, be careful it’s not in recirculation mode (which circulates air through a home but does not exhaust air outside and bring in fresh air) during cooking times.