London - Homeowners should open the window whenever they cook and never dry clothes indoors, according to official guidance on air pollution.
And pregnant women and parents of young children should avoid lighting candles or using cleaning products.
British health watchdog NICE issued the recommendations in an attempt to cut indoor air pollution, an "invisible killer" that is linked to lung and heart disease.
They warned that air-drying clothes inside the house can trigger asthma and urged people to keep the window open when having a bath or shower.
But critics accused health officials of scaremongering. They said public health efforts to tackle air pollution should focus on major issues such as diesel emissions – not "trivial" advice about lighting candles.