Formaldehyde is known to have adverse health effects, and is also found to be a product of atmospheric. photochemical reaction%. Several methods have been employed for the measurement of formaldehyde. Among them, two common methods are comparatively evaluated in this study, i.e. the chromotropic acid method and the HPLC method coupled with 2,4- dinitrophenylhydrazine (DNPH) derivatization of carbonyl compounds. Method evaluation and validation were performed with respect to repeatability, linearity, collection efficiency, and recovery efficiency. Comparison of formaldehyde concentrations measured simultaneously in the field using the two (n=20) and 35.8%, respectively. Overall, the measured levels by chromotropic acid method appeared to ice significantly higher than those by DNPH-HPLC method, indicating a positive interference due to the other aldehydes collected together with formaldehyde.