The main causes of air pollution can be broken down into two distinct categories: natural and human. Natural causes typically include events such as volcano eruptions, dust storms, and forest fires. However, these events occur sporadically. On the other hand, human-caused pollution tends to happen on an ongoing scale. It is largely made up of pollutants emitted from fuel-burning vehicles, factories, waste incineration, smoking, and more.
Recycling used materials uses less energy than making new ones.