Abstract: To investigate acute effects of environmental tobacco smoke on lung function different consecutive smoke concentrations from 0 to 32 ppm CO were required. Therefore a cigarette side-stream smoke generation and dilution system was developped. For a better characterization of the generated sidestream smoke particle concentrations were measured with two nephelometric aerosol monitors. With the developped sidestream smoke generation system we could produce in a short time and held stable different smoke concentrations from 0 to 32 ppm CO. The relationship between CO and particle concentrations was not linear.