The Comisión Ambiental de la Megalópolis (CAMe) announced on February 27, 2025, at 6:00 PM, the suspension of the Phase I environmental contingency due to high ozone levels affecting the Metropolitan Area of Mexico City. This decision marks the end of the restrictions aimed at reducing pollution levels, which were initially enacted after ozone concentrations exceeded the threshold.
On February 26, the levels of ozone reached 157 parts per billion (ppb) at the Tlalnepantla monitoring station, thereby triggering the environmental contingency. This figure significantly surpassed the national limit of 90 ppb established by Mexican regulations and was more than triple the World Health Organization's recommended limit of 51 ppb.
According to the CAMe, the recent monitoring data indicated hourly concentrations of ozone had fallen below the established limits necessary for ending the contingency program. The decision to suspend the contingency was reinforced by forecasts predicting increased humidity levels entering the Valley of Mexico on February 28, resulting in mostly clear skies and improved ventilation conditions. This uptick in humidity is expected to aid significantly in dispersing the atmospheric contaminants.
"Las concentraciones horarias de ozono fueron menores a las establecidas en el Programa para dar por concluida la contingencia," stated CAMe, reflecting the improved air quality.
Officials from the CAMe, along with the Secretaría de Medio Ambiente y Recursos Naturales, emphasized their commitment to continuously monitor air quality and weather conditions closely. They expressed gratitude to the public for adhering to health recommendations during the period of contingency and instruction on pollution mitigation measures.
Environmental authorities noted the light winds and intense solar radiation earlier this week contributed to the accumulation of precursors of ozone, which led to the heightened pollution levels prompting the contingency. Given the significant health impacts of such air pollution, where groups like children, the elderly, and individuals with pre-existing respiratory conditions are particularly vulnerable, these measures were deemed necessary at the time.
During the active contingency, residents were encouraged to remain indoors during peak pollution hours, particularly from 1:00 PM to 7:00 PM. They were also advised against engaging in outdoor activities and smoking within enclosed spaces, aimed at reducing exposure to the contaminated air.
The suspension of the contingency allows for the resumption of normal activities, including commuting vehicles across the Zone Metropolitana del Valle de México (ZMVM). This news is welcome relief for residents who faced restrictions under the "Hoy No Circula" program, which limits vehicle circulation based on license plate numbers to curtail emissions and reduce air pollution during high ozone days.
Transport is now returning to normal, with individuals able to move freely without the previous restrictions impacting their mobility or outdoor activities. The announcement signifies both improvement and continuity as authorities will continue to monitor health risks associated with air quality.
Moving forward, CAMe has reiterated the importance for the public to stay informed about air quality updates, particularly through their AIRE program. Residents can check real-time air quality readings and health recommendations through the Mexico City air quality website and related applications available on major platforms.
Officials advocate for collective responsibility toward maintaining the air quality and protecting public health. New measures are expected and welcomed, as public engagement is key to effectively responding to atmospheric contingencies now and moving forward.
With recent weather changes favoring air dispersion, the general public is advised to keep abreast of air quality information, especially as conditions fluctuate. The longstanding partnerships among various environmental departments aim to mitigate harmful impacts on health and promote awareness surrounding sustainable practices.
This cautious optimism follows years of public instruction on how to react during such atmospheric adversities, reinforcing the principles of environmental stewardship as the residents of Mexico City and surrounding areas navigate through future challenges.
Experts continue to urge communities to collaborate on initiatives aimed at improving urban air quality. Overall, the engagement of the populace remains pivotal for comprehensive solutions to combat pollution.
Proactive participation by all sectors strengthens both environmental policy and community health. Monitoring, reviewing, and acting on air quality will remain priorities for authorities dedicated to ensuring a safer, healthier future for Mexico City.