Contribution of the gasoline distribution cycle to volatile organic compound emissions in the metropolitan area of Mexico City

Species profiles, in-situ photochemistry and health risk of volatile organic compounds in the gasoline service station in China

Accompanying with increases in vehicle population and gasoline consumption, gasoline evaporation accounted for an enlarged portion of total volatile organic compound (VOC) emissions in China, raising increasing environmental concerns especially in megacities. In this study, an intensive sampling campaign was performed in a gasoline service station, to reveal emission characteristics, environmental and health impacts of VOCs. It was strikingly found that 24 % of air samples exceeded the national standard of 4 mg/m³ for non-methane hydrocarbons (NMHCs) on the boundary of the station, with the equipment of Stage I and II controls. VOC groups and species profiles showed that alkanes dominated total VOCs. As typical markers of evaporative loss of gasoline, C4-5 species (i-pentane, n-pentane and n-butane) as well as methyl tert-butyl ether (MTBE) accounted for 49.6 % of VOCs. Species profile and diagnostic ratios indicated the prominent contribution of gasoline evaporative losses from refueling or breathing processes, as well as the interference of vehicle exhaust in the ambient air at the site. Intensive O₃ production was reproduced by the photochemical box model, demonstrating that O₃ formation was co-limited by both VOCs (especially trans-2-butene) and NO_x. Inhalation health risk assessment proved that exposure to hazardous VOCs caused non-cancer risk (HQ = 3.08) and definitely posed cancer risks at a probability of 1.3 × 10^-4 to workers. Remarkable health risks were mainly imposed by halocarbons, aromatics and alkenes, in which 1,2-dichloropropane caused the highest non-cancer risk (HQ = 1.3) and acted as the primary carcinogen (ICR = 5.1 × 10^-5). This study elucidated the high unqualified rate in gasoline service stations after the implementation of latest standards in China, where new regulations targeted halocarbons and updates in existing vapor recovery systems were suggested for VOC mitigation.

Spatiotemporal Variations in Summertime Ground-Level Ozone around Gasoline Stations in Shenzhen between 2014 and 2020

Ground-level ozone has become the primary air pollutant in many urban areas of China. Oil vapor pollution from gasoline stations accelerates the generation of ground-level ozone, especially in densely populated urban areas with high demands for transportation. An accurate spatiotemporal distribution of ground-level ozone concentrations (GOCs) around gasoline stations is urgently needed. However, urban GOCs vary sharply over short distances, increasing the need for GOCs at a high-spatial resolution. Thus, a high-spatial resolution (i.e., 1 km) concentration retrieval model based on the GLM and BME method was developed to obtain the daily spatiotemporal characteristics of GOCs. The hourly ozone records provided by the national air quality monitoring stations and multiple geospatial datasets were used as input data. The model exhibited satisfactory performance (R2 = 0.75, RMSE = 10.86 µg/m3). The derived GOCs show that the ozone levels at gasoline stations and their adjacent areas (1~3 km away from the gasoline stations) were significantly higher than the citywide average level, and this phenomenon gradually eased with the increasing distance from the gasoline stations. The findings indicate that special attention should be given to the prevention and control of ground-level ozone exposure risks in human settlements and activity areas near gasoline stations.

Evaluation of Exposure to Toluene and Xylene in Gasoline Station Workers

The main volatile organic compounds found at gasoline stations are benzene, toluene, ethylbenzene, and xylene isomers (BTEX). They cause several harmful effects on human health. Regulatory Norm 7 (1978) provides that, in Brazil, biological monitoring of toluene and xylene is carried out by measuring the urinary metabolites hippuric acid (HA) and methylhippuric acid (MHA), respectively. The objective of this study was to assess the exposure to toluene and xylene and to identify related signs and symptoms in gasoline station workers. A cross-sectional epidemiological study was conducted with workers occupationally exposed to fuels. These gasoline station workers were divided into two groups: 94 workers exposed mainly by inhalation (convenience store workers (CSWs)) and 181 workers exposed by inhalation and dermal route (filling station attendants (FSAs)). A comparison group was formed by 119 workers not occupationally exposed to fuels (office workers (OWs)). Workers exposed to fuels had higher average levels of these exposure biomarkers (HA and MHA), which were also higher in convenience store workers than in filling station attendants. In addition, individuals exposed to the solvents present in gasoline had altered mood/depression, cramps, dizziness, drowsiness, headaches, irritability/nervousness, weakness, weight loss, and other symptoms more frequently and had higher urinary levels of HA and MHA compared to the comparison group. Gasoline station workers showed high levels of HA and MHA, reflecting high occupational exposure to the solvents toluene and xylene present in gasoline, demonstrating that changes in the current legislation and in the work environment are necessary to ensure better health protection for these workers.

Speciation of non-methane hydrocarbons (NMHCs) from anthropogenic sources in Beirut, Lebanon

The chemical composition of emissions from the different anthropogenic sources of non-methane hydrocarbons (NMHC) is essential for modeling and source apportionment studies. The speciated profiles of major NMHC sources in Lebanon, including road transport, gasoline vapor, power generation, and solvent use were established. Field sampling have been carried out by canisters in 2012. Around 67 NMHC (C2 to C9) were identified and quantified by using a gas chromatograph equipped with a flame ionization detector. Typical features of the roadway emissions included high percentages of isopentane, butane, toluene, xylenes, ethylene, and ethyne. Gasoline evaporation profiles included high percentage of the C4-C5 saturated hydrocarbons reaching 59 %. The main compounds of the power generator emissions are related to combustion. Toluene and C8-C9 aromatics were the most abundant species in emissions from paint applications. Finally, the impact of the use of region-specific source profile is tackled regarding the implication on air quality.