The Environmental Commission of the Megalopolis (CAMe) activated on March 18, 2025, Phase 1 of Environmental Contingency for Ozone in the Metropolitan Area of the Valley of Mexico (ZMVM). This is due to a maximum ozone concentration of 155 parts per billion (ppb) recorded at the Gustavo A. Madero station in Mexico City. Furthermore, the wind has been weak throughout the day, contributing to the sustained high levels of ozone, and it is expected that weather conditions will remain unfavorable for the dispersion of pollutants, which could worsen air quality in the region.
After 2:00 PM, the atmospheric stability of the Valley of Mexico significantly increased, preventing the dispersion of the pollutants that generate ozone. This scenario was favored by the intense solar radiation prevailing throughout the day, promoting the formation of ozone from the accumulated pollutants in the atmosphere.
The measure was taken based on the Programs for Preventing and Responding to Atmospheric Environmental Contingencies of the Governments of Mexico City and the State of Mexico, aiming to reduce the population's exposure to air pollution and mitigate the risk of health impacts, especially in vulnerable individuals such as children, the elderly, pregnant women, and those with respiratory or cardiovascular diseases.
Given this situation, CAMe recommends that the population take measures to avoid exposure to high levels of ozone, especially between 1:00 PM and 7:00 PM, when pollution peaks are most intense. It is advised to avoid outdoor activities during these hours, suspend public or private events that gather people outdoors, postpone outdoor sports or cultural activities during the critical hours, and refrain from smoking, particularly in enclosed places.
CAMe also urges citizens to stay informed about air quality through the "Aire" application, the website www.aire.cdmx.gob.mx, the X account @Aire_CDMX, or by calling the phone number 5552789931 ext.1.
