Biological contaminants such as bacteria, fungi, viruses, animal hair, parasites, mites, pollinators Areas with food debris and moisture such as kitchens and bathrooms; dust; pets; insects and other domestic pests Ventilate moist air; remove leaking pipes and foundations; remove shoes from doors; keep your home clean and pest free. What can contaminate your air – and what can you do about it Count potential sources as a way to reduce exposure Carbon monoxide, a colorless and odorless gas produced during combustion Heating systems, gas stoves, cars in connected garages, fireplaces Ventilation sources directly outside; check the units for proper operation; Heating systems, gas stoves, cars in connected garages, fireplaces Ventilation sources directly outside; Check appliances; fences between garage and house Start with a better understanding of how to balance the movement of air in and out of a house, and the mechanical systems that bring in fresh air and expel old air without compromising energy efficiency – or comfort – in all seasons. Lead, a natural element that may have been present in soils and paints before 1978 Old paint and the dust it generates when it decomposes; contaminated soils Check for lead paint before renewing; never sand, scrape or use a heat gun to remove lead paint With kitchen and bathroom fans, ensure consistent indoor air quality without compromising energy efficiency. While a balanced mechanical ventilation system is the most effective way to improve indoor air quality, here are a few additional steps you can take. But this means that now is a good time to pay as much attention to indoor air quality (IAQ) as to energy efficiency. In most existing homes, mechanical ventilation is limited to bathroom fans and extractor hoods that extract steam or smells from the kitchen. 6 > CLOSED CHILDREN A closed insert regulates both indoor air pollution and energy loss by passing the combustion gases through the chimney and not into the bedroom. But sealing a house to prevent energy loss prevents the healthy air exchange that can be achieved with natural ventilation. Radon, a natural radioactive gas found in rocks, soil and water Cracks in cellars and foundations can enter the house, as well as water pipes that are tested when entering a house and after any renovation that disturbs the surrounding soil. 4 > VENTILATOR BATH The moist and smelly air that can cause mould and mildew to form is ventilated directly to the outside to prevent recirculation into the house’s HVAC system.