La Mexico City and its metropolitan area They live constantly monitoring the state of the atmosphere. In a matter of hours, the air can go from acceptable to bad, with direct implications for the health, mobility, and daily activities of millions of people.
In recent days, official reports have shown how the air quality in Mexico City It varies between "Good", "Acceptable" and "Bad" levels, with worrying peaks on key dates such as Christmas, when the use of fireworks significantly increases the polluting particles in suspension.
Christmas with poor air quality: the impact of fireworks
During the early morning and morning of December 25, the Mexican capital It dawned with poor air quality mainly due to the intensive use of fireworks and other pyrotechnic devices during the Christmas festivities.
According to the monitoring of the General Directorate of Air Quality in the Valley of MexicoHigh concentrations of PM10 and PM2.5 particles were recorded, classified as posing a high health risk. These fine particles, produced by the combustion of materials, remain suspended in the air and can penetrate deep into the respiratory system.
The Environmental Commission of the Megalopolis (CAMe) He insisted in several statements on the need to avoid the burning of fireworks and the making of bonfires, reminding that, in the winter season, low temperatures and frequent thermal inversions prevent pollutants from dispersing normally.
These types of environmental conditions result in repeated episodes of poor air quality during the December holidays, affecting mainly children, pregnant women, the elderly and those suffering from respiratory or cardiac diseases.
Municipalities and boroughs most affected in the Valley of Mexico
The data of the Atmospheric Monitoring System They show that pollution is not distributed evenly. During periods of poor air quality, various areas of Mexico City and the State of Mexico consistently rank among the most affected.
On days with high levels of PM10 and PM2.5, the following have been identified municipalities such as Azcapotzalco, Gustavo A. Madero, Cuauhtémoc, Venustiano Carranza and Álvaro Obregón, along with other districts in the south and east of the city, such as Iztapalapa, Tlalpan, Xochimilco, Milpa Alta, Coyoacán or Magdalena Contreras, with unhealthy levels.
Worrying conditions are also reported in the metropolitan area of the State of Mexico. Municipalities such as Coacalco, Nezahualcóyotl, Tlalnepantla and Tultitlán They often appear repeatedly in lists of poor air quality, especially when pollutants accumulate due to lack of wind and low temperatures.
These records are used to determine whether it is necessary to activate stricter measures, such as Environmental Contingency or the application of the Double No Driving Today program, whose main objective is to reduce vehicular traffic and thus emissions of particles and gases.
How is air quality measured and what do the indices mean?
The monitoring of the air quality in Mexico City and the State of Mexico This is done through an extensive network of automatic stations. The Atmospheric Monitoring Directorate has 16 stations distributed across different boroughs of the capital and 13 additional stations in the State of Mexico.
The equipment continuously measures different pollutants and compares the values obtained with the maximum permissible limits collected in the Official Mexican Standards, as established by National Air Quality Information System (SINAICA)From this data, the Metropolitan Air Quality Index (Imeca) or the Air and Health index used by the city government.
In the Metropolitan Area of the Valley of Mexico, a scale is used with five levels of qualitywhich translate into different degrees of risk for the population:
- GoodThe health risk is considered minimal. The general population and sensitive groups can engage in outdoor activities without special restrictions.
- Acceptable (or “Regular” in some classifications): the risk is considered moderate. People with asthma or other respiratory or heart conditions may experience mild symptoms and are advised that reduce strenuous outdoor exercise.
- MaloThe situation becomes more worrying, especially for those in vulnerable groups. The likelihood of respiratory crises, worsening of lung and heart conditions, and decreased tolerance for physical exertion increases.
- Very bad: are observed more frequently severe respiratory symptoms Cardiovascular problems are also reported in vulnerable populations, including people with pre-existing heart conditions. The risk of premature death is higher in individuals with pre-existing conditions.
- Extremely badThis is the highest level, associated with a significant increase in severe symptoms in the general population. very serious effects In people with respiratory or cardiac diseases, there is a notable increase in the probability of premature death.
This classification guides both the authorities and the public to adjust your daily behavior to the pollution conditions existing at any given time.
Schedule reports, contingencies and Double No Driving Day
La Mexico City Atmospheric Monitoring Directorate It publishes hourly reports detailing pollution levels and ultraviolet radiation intensity in the Mexico City Metropolitan Area. These reports serve both to inform the public and to support decision-making regarding environmental policy.
In several recent outages—such as those at 05:00 a.m. and 15:00 p.m. on different days in December—it has been indicated that the Air quality ranged between “Acceptable” and “Poor”On days with acceptable levels, the risk is considered moderate and outdoor activities are permitted, although caution is advised for those belonging to sensitive groups. When the air quality is classified as poor, the risk becomes high and the recommendations are stricter.
In these situations, the authorities consider implementing measures such as Environmental Contingency or Double No Circulation TodayThe activation of these protocols usually depends on the concentration of pollutants such as ozone (O3) or PM2.5 and PM10 particles, as well as the persistence of high values for several hours.
There are days when, despite registering "Acceptable" levels with moderate risk, the application of the Double No Driving Day program is ruled out because the pollutants do not exceed the thresholds set by the regulations; on other days, when the levels remain in the "Bad" range and the risk is high, the application of additional restrictions on movement and industrial activity to try to reduce the pollutant load in the air.
Ultraviolet radiation and outdoor activity
The hourly reports not only detail the state of the pollution, they also report on the ultraviolet (UV) radiation indexThis is relevant information for those who spend time outdoors. On different days in December, levels ranging from 0 to 4 have been observed, indicating very different conditions for sun exposure.
With UV indices of 0 or 2, authorities indicate that, in general, no special protection is necessary When exposed to the sun, although the basic recommendation to protect the skin remains for very sensitive individuals, when the index reaches values close to 4, it is recommended to wear a hat, sunglasses with UV protection, and sunscreen with a factor of 30 or higher, especially during the midday hours.
The combination of a air categorized as “Bad” A high UV index requires extra precautions: limiting time spent outdoors, avoiding strenuous physical activity, and protecting both the respiratory system and skin. Conversely, on days with "Good" or "Acceptable" air quality and low radiation, outdoor activities can be carried out with relative peace of mind, especially for those who are not part of vulnerable groups.
The situation of Mexico City in the national and international context
Local data from Mexico City fit into a much broader national and regional picture. Several reports, including the IQAir World Air Quality Report 2024They emphasize that Mexico is among the Latin American countries with the highest levels of air pollution.
This study indicates that the average annual concentration of particles PM2.5 In Mexico it was approximately 3,5 times higher to the reference value recommended by the World Health Organization (WHO). These particles, made up of organic compounds, dust, soot, and metals from vehicles, industries, and waste burning, are especially dangerous because they can reach the bloodstream.
The Mexican capital It slightly surpasses cities like Santiago de Chile in fine particulate matter concentration, reflecting the magnitude of the challenge facing one of the largest and most densely populated metropolitan areas in the region. Other Mexican cities, such as Monterrey, also show high PM2.5 levels, confirming that air pollution is not a problem exclusive to the Valley of Mexico.
This context reinforces the need to public policies sustained over time, combining traffic restrictions, modernization of public transport, stricter industrial regulations and waste management measures, in addition to ongoing public information campaigns.
Recommendations for the public in the event of episodes of poor air quality
Faced with days of high pollution levels, environmental and health authorities are emphasizing a series of measures practical recommendations to reduce exposure and minimize health risks, especially for vulnerable people.
At “Bad” levels or higher, it is advisable Avoid strenuous outdoor physical activityActivities such as running, playing sports, or heavy outdoor work should be avoided. Children, the elderly, pregnant women, and those with respiratory or heart conditions should stay indoors as much as possible and avoid areas with heavy traffic.
If symptoms such as difficulty breathing, persistent cough, eye or chest irritation, or a feeling of tightnessIt is recommended to stop any exertion and seek medical attention. In some cases, it may be advisable to use masks designed to filter fine particles, although their effectiveness depends on the type of filter and how well they fit the face.
It is also suggested ventilate the house During times of the day when pollution is lower, avoid burning trash or materials at home and reduce the use of private cars when pollution levels are high, opting for public transport or carpooling whenever possible.
The role of monitoring stations and citizen information
Real-time tracking of air quality in the Metropolitan Area of the Valley of Mexico This is made possible by a network of stations distributed across different municipalities and boroughs. Each station continuously measures the concentration of pollutants, and its data is integrated into specialized computer systems that model the chemistry and dynamics of the atmosphere.
Official reports detail that municipalities such as Tlalpan, Benito Juárez, Azcapotzalco, Coyoacán, Cuajimalpa, Gustavo A. Madero, Cuauhtémoc, Venustiano Carranza, Miguel Hidalgo, Álvaro Obregón, Iztapalapa or Tláhuac They have one or more stations, which explains why they appear repeatedly in the lists. The same occurs in municipalities in the State of Mexico where measurement points are located, such as Atizapán, Chalco, Cuautitlán Izcalli, Naucalpan, Nezahualcóyotl, Ecatepec, Tlalnepantla, Tultitlán, or Coacalco.
The various reports from December include combinations of results ranging from "Good" and "Acceptable" to "Poor," depending on the day, time, and location. Some stations are temporarily labeled as such. “No data or under maintenance”which indicates that they are under review or are not sending valid information at that time.
For citizens, regularly checking these reports—before going to work, school, or to exercise—has become a basic tool for planning the dayThe general recommendation is to check both the air quality index and the UV level and, based on that, adjust the intensity and timing of outdoor activities.
With a scenario in which the air quality in Mexico City It can change in a few hours; the combination of constant monitoring, transparent information, and prevention measures has become essential to live with a problem that, far from being isolated, is part of the daily reality of the metropolis and demands both public policy decisions and small daily adjustments from each person.
