Environmental health comprises the parts of human health, disease and injuries that are determined or influenced by environmental factors. Environmental factors include chemical, physical, biological and social agents (housing, urban development, land use, transportation. Not only environment effects health, genes can play a role as well. Environmental factors that effect human health include air, water, soil and manmade environment (created by society) Atmosphere: carbon dioxide increased 30% since the beginning of the industrial. Geosphere: 1/3 to the land surface has been transformed by human action. Declining health of other organisms is the clearest indicator of environmental threats to human health. Factors effecting human health include increased uv, traces of toxic chemicals, infections (fungi and bacteria), predators. Environmental factors are responsible for 25% of all preventable diseases. Diarrhea and respiratory infections are the main effects of environmental factors difficult to assess - difficult to prove that air pollution or environment cause diseases.