Sulfuic acid is widely used in many industries, which is associated with the exposure of a large group of employees to this harmful substance. In 2012, a new value of occupational exposure limit for sulfuric acid as the thoracic fraction was introduced in Poland. Due to this change, the method enabling determination of sulfuric acid in the thoracic fraction has been established in accordance with the requirements of the Standard No. EN 481. The practical use of this method indicated the necessity of modificating the procedure for sulfuric acid extraction from methylcellulose filters. The aim of this study was to modify the extraction method of sulfuric acid(VI) and to validate the ion chromatography method. The determination of sulfuric acid(VI) with ion chromatography with conductivity detection was applied in this study. The study used an analytical column IonPac® Dionex AS22 (4 × 250 mm) with a precolumn Dionex IonPac AG22 (4 × 50mm) and a mixture of carbonate and bicarbonate, as a carrier phase of an isocratic flow rate 1.2 ml/min. The proposed conditions for the chromatographic separation of ions enabled the determination of sulfuric acid (VI) in the presence of fluoride ions, acetate, chloride, bromide, nitrate, nitrite and phosphate. Parallel Particle Impactors (PPI) with mixed cellulose filter dedicated for thoracic fraction was used for sampling. The determination method was achieved at 2.125 μg/m3 for 480 m3 of air and extraction of MCE filter with water (10 ml). The detection limit calculated on the basis of the signal-to-noise ratio was 1.9 ng, and the limit of quantification was 5.7 ng. The uncertainty of the overall method is 11% and 23% of expanded uncertainty. PPI sampler dedicated to collect thoracic fractions has been tested in real conditions in factories producing and processing sulfuric acid. The method of vacuum filtration for sulfates extraction from filters MCE, which was published in The Principles and “Methods of Assessing the Working Environment” (PiMOŚP), was modified. The use of a mechanical shaking MCE filter with ultrapure water Milli-Q for 30 min enabled to receive approximately 100% recovery of sulfuric acid from the filter analyzed while avoiding the leaching of interferents. The results confirmed the presence of sulfuric acid(VI) in the thoracic fraction of aerosol tested at concentrations ranging from 0.03 to 1.47 MAC value.