The document discusses various sources of nanoparticle exposure and their potential health effects. It addresses nanoparticles from diesel exhaust, indoor air pollution from activities like cooking, cigarette smoke, demolition sites, and engineered nanoparticles used in consumer products. Some key points include: - Diesel exhaust nanoparticles can increase cardiovascular risk and lung cancer risk. - Indoor activities are a major source of indoor air pollution and nanoparticle exposure. - Cigarette smoke contains nanoparticles that increase cancer and respiratory disease risk. - Demolition sites release asbestos and other toxic nanoparticles that can cause respiratory symptoms. - Engineered nanoparticles are used in cosmetics, clothing, and other products but their health effects after exposure are still being studied.