Bethany Wieman of SF Gate Home Guides notes that pollution affects humans and other living things in a number of ways, including an increased risk of asthma. This is due to the high level of carcinogens in the particles and gases that make up air pollution.
Water pollution harms humans when it enters clean water supplies. This directly affects those drinking the water and indirectly affects those who consume food grown by farmers using the contaminated water to irrigate their crops. Those who drink contaminated water may develop short- and long-term health problems. People who enjoy using lakes and rivers for recreation are also affected by industrial waste and agricultural runoff that ends up in the water.
Littering affects humans by increasing their risk of injury. Children are particularly susceptible to injury by bottles or other discarded items that do not break down easily. Litter also affects the beauty of littered areas. Certain types of litter in the ocean may cause toxic substances to accumulate, which may be ingested by fish that humans later ingest, causing further illness.
Soil contamination may affect humans that breathe in the dust of contaminated soil, and humans may ingest plants grown in contaminated soil and fall ill.