Posted By David Kinnison
A quick and simple method is to employ Draeger tubes. Basically an air sample is drawn over the tube at a given flow rate and watch the indicator change colour (degree of change relates to the concentration of SO2). Most laboratory suppliers will have Draeger equipment (pump and tubes) of try Draeger Safety (on the web I believe).

For continuous monitoring a dedicated detector would be appropriate. There are several makes on the market. (Thermo Electron, Draeger, Annox).

Hope this helps

Dave