Forest fires

Volcanic eruptions

Wind erosion

Gases released from body processes

Natural radioactivity

Burning of fossil fuels

Waste incinerators

Manufactoring activities

Mining activities

Petroleum refining

Emissions from transportations

Insecticides, fertilizers and pesticides

The using of syntetic materials

Reducing ventilation

Heating

Cooking

Smoking

Cleaning products

Aereosol

Paints

Sprays