Introduction: Air pollution is one of the most important health and environmental topics today. Most people, that means 99% of the global population, breathe air that exceeds WHO guideline limits. Benzene, toluene, and xylene belong to an important group of outdoor pollutants. Transport is one of their main sources. Exposure to benzene, toluene, and xylene can be deleterious to human health. Therefore, methods to prevent and reduce them in outdoor air are very important. Purpose: The purpose of the master's thesis was the development of a method for adsorption of benzene, toluene, and xylene from air on alternative low-cost biochar and determination of its effectiveness. We wanted to find out how two different granulations of biochar (<0.25 mm and 0.25–0.5 mm) affect different levels of adsorption. We were also interested in how the mass of biochar affects the amount of adsorbed benzene, toluene, and xylene. Methods: We used two different granulation filters (<0.25 mm and 0.25–0.5 mm) to test the adsorption. In the first part of the experiment, we determined the sensitivity of the method on the model compound, which was toluene in our case. We were looking for a measurable concentration of toluene and a proper mass of the filter, which could retain toluene. An occupational exposure limit value (192 µg/L) was used as a measure of toluene adsorption effectiveness. The adsorption of toluene on biochar was measured applying solid phase microextraction followed by gas chromatography-mass spectrometry. In the second part of the experiment, the applicability and repeatability of the method were upgraded by measuring benzene and xylene. Three replicates of the adsorption were performed for all three pollutants. Results: We determined measurable toluene concentrations: 174 μg/L and 87 μg/L, which represents a range low enough for occupational exposure measurements. The results showed that both granulation filters (<0.25 mm and 0.25–0.5 mm) also adsorbed benzene and xylene well. Discussion and conclusion: We found out that smaller filter granulation and larger filter mass provide more effective adsorption. The large active surface area allows a large amount of adsorption. We also found out that the method is repeatable for all tested compounds and both filters. Both filters showed the potential for reducing benzene, toluene, and xylene from outdoor air. The result of our research may be the starting point for further research, for example using biochar in practice for reducing benzene, toluene, and xylene from outdoor air and investigating adsorption of other pollutants from the air.
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