Evaporative volatile organic compounds from the actual vehicle refueling emissions: Characteristics, secondary transformation, and health effects in winter and summer seasons

Abstract

Volatile organic compounds (VOCs) emissions from the vehicle refueling process is an increasingly significant issue. However, the gasoline formulation showed seasonal variation, potentially leading to the alterations of VOC components during the refueling process. Refueling VOCs of different gasoline and diesel were collected at some typical gas stations during both summer and winter to analyze their seasonal emissions characteristics, environmental impacts, and associated health risks. The refueling VOC profiles in summer consisted of a notably higher proportion of small oxygenated VOCs (C3) and a significantly lower content of halocarbons compared to those in winter, which indicated that the refueling VOC profiles in just a single season failed to capture characteristics of the entire year. The OFP values of gasoline vapor in two test seasons were consistent (around 2.9 g O₃/g VOCs), with the dominant species of acrolein (15.7 ± 2.5%) in summer and i-pentane (23.2 ± 2.1%) in winter. Aromatics contributed the most to secondary organic aerosol formation potential (SOAP), with toluene (65.4%, summer; 48.5%, winter) being the overwhelmingly dominant species. The assessment of inhalation health risks indicated that exposure to adverse VOCs resulted in definite non-cancer risk (HQ = 5.9) and cancer risk (ICR = 4.6 × 10⁻⁴) to the gas station attendant, which exceeded the acceptable level, with 1,3-butadiene exhibiting the highest toxicity and a dual toxicity risk. The impact of VOCs on health was more severe during winter compared to summer. It is recommended that seasonal influences should be considered when controlling VOC pollution at gas stations.