The pollution sources produce noxious emissions, harmful to the environment and the public health. District 4 of the city of Bucharest is considered to be very polluted due to factors such as industry, heavy traffic, building sites,thermoelectric power plants, sources of diffusive combustion, and also the reduction of green spaces. These sources produce both noxious emissions and noise pollution. The air contamination, the water and soil pollution contribute to the deterioration of public health. Keeping a record of all the pollution sources, being aware of all their characteristics and the emissions they produce, as well as keeping them under strict control can be considered the necessary premises for maintaining a satisfying quality of the environment.