Second Hand Smoke
Cigarette smoke is a potent cocktail of over 7,000 different substances and chemicals in both particulate and gas molecule forms, around 70 of these are known to cause cancer. It is also bad for the heart and lungs and is a potent trigger of asthma attacks. Cigarette smoke is a difficult contaminant to filter out of the air. However, you can significantly reduce your exposure to it by using an air purifier with the right filtration technology.