Ecology is a scientific branch which studies interactions between organisms and their environment. It also studies the biodiversity of our planet. Earth is the only planet in the solar system where there is life. It is home to various kinds of plant and animal species. For centuries people lived in harmony with their environment until industrialization began. It brought human society into conflict with nature, which today has grown to a dramatic scale. Every year industrial waste pollutes surrounding atmosphere with millions of tons of dust and harmful substances. The most acute problems include shortage of natural resources, global warming, acid rains, wildlife extinction, water and air pollution. Air pollution is one of the most important and urgent problems. It is mostly caused by transport and factory fumes, which gradually destroy the ozone layer. Unfortunately, this can have dire consequences, as the ozone layer is there to protect our planet from sun radiation. Most aerosols whi