An exploratory study of volatile and semi-volatile organic compounds in PM_2.5 atmospheric particles from an outdoor environment in Brazil

The development of methods for determining volatile and semi-volatile organic compounds in public spaces has become necessary to identify potential health and environmental risks. This study presents a practical methodology for sampling, extracting, detecting, and identifying these compounds in a vehicular traffic region in Belo Horizonte, Brazil. The methodology uses direct-immersion solid phase microextraction (DI-SPME) and static headspace (SHS) to extract SVOCs/VOCs. Comprehensive time-of-flight gas chromatography mass spectrometry (GC×GC/Q-TOFMS) and gas chromatography coupled to mass spectrometry (GC/MS) were used to detect and identify compounds. The analysed samples, collected with a high-volume sampler (Hi-Vol) with quartz filters and in which particulate matter (PM_2.5) was retained, showed the presence of more than 200 compounds, both biogenic (natural origin) and anthropogenic (human origin). Regarding the distribution of chemical classes, aromatic compounds were predominantly found at 29.2%, followed by esters at 20.8%, non-aromatic hydrocarbons at 5.6%, and carboxylic acids at 9.4%. Static headspace gas chromatography (HS-GC) enabled the identification and quantification of 21 volatile compounds, including BETX, dichloromethane, chloroform, and naphthalene, which are currently regulated by the US Environmental Protection Agency (EPA).