Volatile organic compounds (VOCs) in urban public transportation: Seasonal influences and variations

The present work aims to analyze the information related to the organic pollutants present inside the public transport units of León Guanajuato, Mexico, along winter, spring and fall seasons. Through the application of different selection criteria, a database was generated that allowed the analysis of the different selected pollutants and determine their behavior throughout the spring, autumn and winter seasons. These analyzes were carried out using different statistical tools like ANOVA, PCA, and correlation network maps. At least 23 compounds were selected as common pollutants along all the seasons, including aromatics, aliphatic, halogenated, polycyclic, and compounds with heteroatoms species. Results showed that the concentrations of Volatile Organic Compounds s such as hexane (1.5–3.0 µg/m³), dichlorobenzene (2.0–4.5 µg m −3 ), and toluene (5.0–12.0 µg m −3 ) varied significantly across the seasons, with higher levels observed in winter. The study highlights the influence of external environmental factors on indoor air quality within public transport units proven through statistical analysis. The results allowed to mention that the concentrations of Volatile Organic Compounds can vary significantly in different season along the year, as well as that the main pollutants vary according to the season, of which there are compounds that are only present during these periods. • At least 23 compounds were identified as persistent pollutants inside bus cabins. • Xylene is the VOC that best represent the general contamination inside the units. • The formation of groups and clusters allowed identify emission sources. • Groups and clusters were formed especially due the presence/absence phenomena. • Each season differs significantly from each other in terms of VOC type and levels.