Cleaning the house is as bad for women's lungs as smoking a pack of cigarettes a day, a new study finds, but the same products had no effect on men. Researchers assessed the lungs of 6,235 women and men, then checked on them again over the course of 20 years. They were asked if they cleaned their own house, or worked as professional cleaners, and how often they used liquid cleaning products and sprays. Women who cleaned – either around the house as little as once a week or as professional cleaners - had an 'accelerated' decline in lung capacity comparable to smoking a pack a day for 10-20 years. The effect was not observed in men, which is in line with previous research that has found male lungs are more resistant to damage from various irritants, including smoke and wood dust.