Which of the following is a common indoor air pollution source in developing countries?

• A. Gasoline vehicle exhaust indoors
• B. Cooking with solid fuels such as wood or coal
• C. Industrial solvent leaks
• D. Factory chimneys

Answer: (B)

The main idea here is that indoor air pollution in many developing countries comes from how people cook and heat their homes. When solid fuels like wood or coal are burned inside kitchens or living spaces, especially in poorly ventilated stoves or open fires, the burning releases a lot of smoke and pollutants. Particulate matter (PM), carbon monoxide, and other toxic gases accumulate indoors, leading to high exposure for everyone in the home and serious health risks over time.

Gasoline vehicle exhaust indoors, industrial solvent leaks, or emissions from factory chimneys are typically outdoor or workplace sources or require specific conditions (like being in an enclosed garage or industrial setting). They aren’t the common, everyday indoor pollution source in the context described, where the household uses solid fuels for cooking. Cleaner stove technologies, better ventilation, or switching to electricity or cleaner fuels are ways to reduce this exposure.