Atmospheric ethene concentrations in Mexico City: Indications of strong diurnal and seasonal dependences

Monitoring of atmospheric ethene was carried out in Mexico City with a 12C16O2-laser-based photoacoustic spectrometer. We assessed the variation of the ethene content in atmospheric samples simultaneously collected in stainless-steel containers at three stations of the local government's air quality monitoring network in November 1999 and March 2000. The ethene levels in November were higher than those detected in March, reaching up to 36.9 ppbV. In addition, continuous measurements of ethene were carried out in February 2001 for 1 week, with a time resolution of 1 min. It allowed recording of real-time ethene levels of up to 68 ppbV. A comparison between ethene profiles recorded on weekends and working days clearly shows a pronounced difference in concentration, which is almost three-fold higher on working days.