There is increasing evidence of a causal link between airborne particles and ill health and thisstudy examined the exposure to both airborne particles and the gas phase contaminants ofenvironmental tobacco smoke (ETS) in a bar. The work reported here utilized concurrent andcontinuous monitoring using real-time optical scattering personal samplers to recordparticulate (PM10) concentrations at two internal locations. Very high episodes were observedin seating areas compared with the bar area. A photo-acoustic multi-gas analyser was used torecord the gas phases (CO and CO2) at eight different locations throughout the bar andshowed little spatial variation. This gave a clear indication of the problems associated withachieving acceptable Indoor Air Quality in a public space and identified a fundamentalproblem with the simplistic design approach taken to ventilate the space. Both gaseous andparticulate concentrations within the bar were below maximum recommended levels althoughthe time-series analysis illustrated the highly episodic nature of this exposure.