The Environmental Commission of the Megalopolis (CAMe) has declared the activation of Phase 1 of Environmental Contingency for ozone in the Metropolitan Area of Valle de Mexico starting at 5:00 PM on February 26, 2025. This measure was taken after maximum ozone concentrations of 157 parts per billion (ppb) were recorded at the Tlalnepantla station, located in Tlalnepantla de Baz, State of Mexico.
These high ozone concentrations have been attributed to a high-pressure system over the eastern part of the Valley of Mexico, which has generated light winds with variable direction, combined with intense solar radiation. These conditions have facilitated the accumulation of ozone precursors in the atmosphere, favoring the formation of the pollutant.
In this context, a series of recommendations have been issued for the population in order to reduce exposure to high levels of pollution. Citizens are advised to stay informed about air quality and follow health guidelines, especially during the critical hours from 1:00 PM to 7:00 PM. They are urged to avoid outdoor activities during this period, as well as engage in physical exercise. Additionally, it is recommended to postpone planned mass outdoor events during this time frame and it is suggested not to smoke in enclosed spaces.
CAMe also recommends specific measures for reducing emissions, such as promoting remote work and conducting online transactions to decrease commuting, avoiding the use of products that contain solvents, refueling at specific times, and repairing leaks in domestic gas installations. These measures aim to contribute to the improvement of air quality and reduce pollution levels in the region.
