The bachelor`s thesis presents the procedure of measuring fire-box waste gas emission that was used at the Faculty of Geotechnical Engineering in Varaždin. After the introduction, the second part provides an explanation for the emission of fossil fuels, their combustion and their harmful impact on the environment and human health, as a result of which power supply policies are being changed and solutions to decrease smoke gas emission in the atmosphere are being searched for. The third part of this paper explains the sources of emissions, the composition of smoke gases, as well as the legislation related to air protection and monitoring of pollutant emissions into the air from stationary sources. The fourth part describes the procedure of measuring carbon monoxide, nitrogen oxides and hydrogen sulfide smoke gas emission based on the example of a fire-box. The procedure for measuring the content of CO, NOX, NO2, NO and H2S using a Testo 350 smoke gas analyzer, which was used at the Faculty of Geotechnical Engineering, is presented in detail. The results obtained by measuring CO are compared with the measurement results made by the company MIKA d.o.o. The obtained values of carbon monoxide and nitric oxide concentration are compared with the limit values for small appliances that use gas fuels in accordance with applicable legislation.