Atmospheric aldehydes in indoor and outdoor environments impacted by combustion emissions of diesel/biodiesel mixtures

The temporal evolution of air pollutants concentrations inside a semi-closed bus station has been investigated since 2002 until 2023 to understand the impact of direct combustion emissions from buses using diesel/biodiesel fuel blends (B3-B12). Carbonyl compounds concentrations were evaluated, which predominance of acetaldehyde and formaldehyde. It is known that acrolein emission increases with the addition of biodiesel to diesel. However, the determination of acrolein by the official method is compromised due to coelution with acetone on liquid chromatographic separation. In this work, with adaptation of the mobile phase, acrolein was separated adequately and could be determinate in samples obtained in the same bus station while the vehicles had been using B12 fuel blends. Concomitantly, samples were collected outside the station to compare indoor and outdoor air quality. Formaldehyde, acetaldehyde and acrolein were detected in both environments. Aldehydes concentration was higher indoor than outdoors. There are indications that acrolein levels may increase with higher proportions of biodiesel in diesel blends. This study valuable information for future studies on air quality and vehicular emissions.