Tobacco smoke and wood smoke are similar in many ways. Suspected carcinogens in cigarette smoke, such as benzo(a)pyrene and formaldehyde, are also present in wood smoke. Assuming than an average smoker smokes around 40 cigarettes a day, the exposure of a person cooking with biofuels can be compared to both active and passive (second-hand) smokers. Active smokers inhale pollutants with every "puff', but a filter absorbs some of the toxins present. But both passive smokers and people who cook with biofuels are exposed with every breath.

Chronic bronchitis one of the diseases prevalent among smokers. It predominantly affects men in the developed world. However, in the developing countries, despite the fact that men smoke much more heavily than women, both groups are equally affected by chronic bronchitis. Exposure to biomass fuels at home for several hours every day and over several years is responsible for the disease in women. This leads to pulmonary hypertension and cardiac enlargement, resulting in cor pulmonale (enlargement of the right side of the heart).