Aldehyde emissions from two types of sources were measured by three measurement method approaches. The two sources were a municipal incinerator and a phenolic resin manufacturing process. The three measurement methods were: collection of the aldehydes in a basic peroxide solution with subsequent detection by Ion Chromatography, collection of the aldehydes in a bisulfite solution with subsequent determination of total carbonyl with a titrimetric procedure, and collection of the aldehydes in a dinitrophenylhydrazine solution followed by detection of the respective derivatives by high performance liquid chromatography. The results indicate several limitations to the peroxide approach and potential collection efficiency problems with the derivative method. The need to develop further measurement methodology for such sampling and detection exists.