Spatiotemporal Variations in the Air Concentrations of 1,3-Butadiene in Intra-Urban Environments: a Case Study in Southern Mexico City

The high ozone formation potential and proven toxicity of the 1,3-butadiene (1,3-BD) make it a target compound for monitoring and regulating its emissions. However, the Mexico City Metropolitan area (MCMA) has no routine measurements or regulations for this pollutant. Three sampling campaigns were conducted to measure 1,3-BD in two locations of the MCMA. The sampling sites differ in the amount and type of activities they hold: a university campus and a gas station located on a principal road. Sampling and analysis followed the United States Environmental Protection Agency method for Toxic Organics TO-14A. The results showed that concentrations in the gas station (3.09 ppb) were significantly higher than those in the university area (0.71 ppb), suggesting that exhaust emissions are the primary 1,3-BD source within urban environments. The seasonal comparison disclosed that emissions of 1,3-butadiene are higher during the warm season (April–May), which coincides with the high ozone season in the city. The weekdays and weekend concentrations did not show any significant difference. Due to its high potential for ozone formation and harmful health effects, it is essential to continuously measure the concentrations of 1,3-butadiene and regulate its emissions to improve the air quality of the MCMA.