This standard describes the procedure and equipment for the determination in the airborne at the workplace, of the anions of sulfuric acid and phosphoric acid and their mixtures, through the sampling on a membrane filter and the subsequent analysis by ion chromatography. This method is applicable to the determination of the inhalable fraction of airborne particles defined in UNE-EN 481, provided that the appropriate sampler is used. The procedure of measurement described can be used to carry out measurements to determine the occupational exposure concentration, measurements for comparison with limit values (occupational) to evaluate the exposition via inhalation and periodic measurements. It may also be used to carry out screening measurements of time weighted average concentration (see UNE-EN 482, 4.2) and screening measurements of variation of concentration in space (see UNE-EN 482, 4.3). It cannot be used to measure instantaneous concentrations or fluctuations of the concentration in short periods of time.