Air Pollution Emergency Days: Mexico City's Struggle

Mexico City has long struggled with air pollution, and in 2019, wildfires and high temperatures exacerbated the issue, leading to an environmental emergency declaration. While the Mexican government has implemented measures to improve air quality, the city's topography and rapid industrialization have contributed to persistent pollution issues. With pollution levels impacting the health of residents and the economy, finding effective solutions remains a critical challenge.

Mexico City's air pollution history

Mexico City has made significant strides in improving its air quality and reducing air pollution, dropping from being ranked as the world's most polluted city in 1992 to the 917th most polluted city in 2021. This transformation is especially remarkable given the city's history of severe air pollution.

During the 20th century, Mexico City underwent rapid industrialization and urbanization, attracting thousands of migrants and causing its population to skyrocket. The metropolitan area, known as Greater Mexico City, grew from 3.1 million in the 1950s to 14 million in the 1980s, and by 2015, the population had reached 20 million. This unprecedented population boom fueled the industrialization process, leading to the proliferation of vehicles and the establishment of factories, power plants, and oil refineries.

The combination of industrial activities, vehicle emissions, and the city's topography contributed to the dire air quality. Mexico City is located in a basin, which naturally traps air pollutants. The incomplete combustion of carbon-based fuels due to the city's high altitude further exacerbated the problem. As a result, ground-level ozone, carbon monoxide, sulphur dioxide, nitrogen dioxide, and airborne particles reached record levels in the 1980s and 1990s. The toxicity of the air was so severe that birds fell from the sky, dead.

Recognizing the urgency of the situation, the Mexican government implemented various measures to combat air pollution. They mandated the reformulation of gasoline, closed or relocated polluting factories, and introduced vehicular restrictions, such as the ""Hoy No Circula" program, which prohibits certain vehicles from being driven on designated days. The government also invested in sustainable mobility options, including cycling infrastructure and electric buses, and joined the global Breathe Cities initiative to access additional resources for tackling air pollution.

These efforts yielded notable results. By 2012, ozone and other air pollutant levels in Mexico City had dropped to those comparable to Los Angeles. While Mexico City still faces challenges, such as the need to increase green areas and comply with certain emission standards, its progress in improving air quality is undeniable. The city's successful strategies serve as a model for other urban centers grappling with air pollution, demonstrating that even historically polluted cities can make substantial improvements with targeted policies and interventions.

The impact of air pollution on citizens

Mexico City has long struggled with air pollution, which has been a concern for the city's population and health officials for decades. In 1992, the United Nations named Mexico City "the most polluted city on the planet". The city's high altitude, rapid industrialization, population growth, and proliferation of vehicles have all contributed to this issue. While the air quality has improved significantly since then, dropping to the 917th most polluted city in the world in 2021, the concentration of airborne particles still exceeds the World Health Organization's guidelines.

The impact of air pollution on the citizens of Mexico City has been significant. It is estimated that air pollution causes about 5.9% of all deaths in the country. Those with heart disease, coronary artery disease, or congestive heart failure are particularly at risk, along with pregnant women, children under 14, senior citizens, and those who work outdoors. The health effects of air pollution include respiratory problems, such as lung disease, allergies, rhinitis, and conjunctivitis, as well as eye irritation and a runny nose.

The Mexican government has implemented various measures to reduce emission levels, including vehicular restrictions, the expansion of public transportation, and the promotion of active transport such as cycling and walking. However, the effectiveness of some of these policies has been questioned, as people have often chosen to buy additional cars to drive on restricted days rather than use public transportation.

To further improve air quality and protect citizens' health, it is essential to tackle the problem at its source. This includes modifying mobility systems to prioritize electric public transport and active transport, as well as updating and expanding environmental health standards to align with the World Health Organization's guidelines. Additionally, there should be a focus on reducing energy consumption, promoting cleaner and more efficient energy sources, and increasing environmental education and citizen participation in sustainability initiatives.

While Mexico City has made remarkable progress in reducing air pollution, there is still work to be done to ensure the health and well-being of its citizens. By addressing the root causes of the problem and encouraging citizen engagement, the city can continue to improve its air quality and create a healthier environment for its residents.

Governmental responses to air pollution

Mexico City has long struggled with air pollution, and the Mexican government has implemented various measures to address this issue.

In 1989, the Mexican government introduced "No-Drive Days", or "Hoy No Circula", prohibiting drivers from using their vehicles one day per week. This policy was later expanded to include Saturdays in 2008. While this initiative aimed to reduce vehicle emissions, its effectiveness has been questioned as some residents opted to purchase additional cars to drive on restricted days.

The Mexican government has also focused on regulating fuel standards and industrial emissions. They mandated the reformulation of gasoline and the relocation or closure of polluting factories. These measures, along with the expansion of public transportation and the implementation of low-sulphur fuel standards, contributed to significant reductions in carbon monoxide, ozone, and particulate matter levels between 1992 and 2012.

In 2016, the Mexican Atmospheric Environmental Contingency Plan (AECP) was reactivated to address seasonal spikes in air pollution. This plan included further restrictions on vehicle usage, limiting driving to two days a week, and reducing greenhouse gas emissions from factories by up to 40%.

Additionally, the city's government launched ProAire in 1995, a comprehensive program aimed at improving air quality in the metropolitan area. This program was developed in collaboration with the Metropolitan Environmental Commission (MEC) to address the city's severe pollution levels.

Despite these efforts, air pollution remains a concern in Mexico City, and the government continues to face challenges in enforcing effective policies. The city's high altitude, rapid industrialization, and proliferation of vehicles contribute to persistent air quality issues.

The effectiveness of vehicle restrictions

Mexico City was once dubbed the world's most polluted city by the United Nations in 1992. The city's high altitude, which causes its oxygen levels to be 25% lower, the proliferation of vehicles, rapid industrial growth, and a population boom are all contributing factors.

To tackle this issue, the Mexican government implemented several measures, including requiring gasoline to be reformulated, closing or relocating polluting factories, and prohibiting drivers from using their cars one day per week. The ""Hoy No Circula" program was introduced in 1989, restricting vehicles from being driven one weekday per week based on the last digit of the vehicle's license plate. Under this program, vehicles are issued a hologram sticker based on the results of their emissions test, with cars that meet the requirements being exempted from the restrictions.

In addition to the "Hoy No Circula" program, Mexico City has implemented further restrictions on vehicle use, such as the Mexican Atmospheric Environmental Contingency Plan (AECP), which was reactivated in 2016 and restricted driving to two days a week instead of one. The city has also expanded its public transportation system and increased bicycle accessibility.

While the effectiveness of vehicle restrictions may vary depending on various factors, they have played a role in improving Mexico City's air quality, and the city continues to implement and adjust these measures to combat air pollution.

The role of topography in air pollution

Mexico City has long struggled with air pollution, which reached its peak in the 1980s and 1990s. In 1992, the United Nations declared it the world's most polluted city. The city's topography, high altitude, and rapid population growth have all contributed to this issue.

Located in a basin, Mexico City's topography has played a significant role in its air pollution problem. The city sits in a valley, 7382 feet above sea level, causing its oxygen levels to be 25% lower. This high altitude, coupled with the basin-like topography, creates a perfect storm for trapping air pollutants. The basin-like shape of the surrounding land traps the polluted air, preventing its dispersion, and the thin air at high altitudes exacerbates the issue.

The topography of Mexico City did not favour its rapid industrialization and urbanization during the 20th century. As the population grew from 3.1 million in the 1950s to 14 million in the 1980s, the increase in human activities severely impacted the air quality. The proliferation of vehicles, rapid industrial growth, and the use of carbon-based fuels all contributed to the air pollution crisis. The basin-like topography, combined with these human activities, created a situation where air pollutants were concentrated and trapped, leading to the record-high levels of ground-level ozone, carbon monoxide, sulphur dioxide, nitrogen dioxide, and airborne particles in the 1980s and 1990s.

To combat air pollution, the Mexican government has implemented various measures, including the ""Hoy No Circula" policy, which restricts vehicles from circulating based on their emissions performance. While this has had some impact, evidence suggests that people often circumvent this policy by purchasing additional cars to drive on restricted days. Other measures, such as requiring gasoline reformulation, closing or relocating polluting factories, expanding public transportation, and increasing green areas and bicycle accessibility, have also contributed to significant improvements in air quality.

As a result of these efforts, Mexico City has dropped to the 917th most polluted city in the world in 2021, according to IQAir. However, the city still faces challenges, particularly with ground-level ozone, which remains a significant concern. In the spring of 2016, ozone levels were almost 1.9 times the acceptable limit, and in May 2019, the government declared an extraordinary atmospheric environmental contingency due to high levels of harmful particles in the air. While Mexico City has made remarkable progress in improving its air quality, continued efforts and aggressive policies are necessary to address the remaining issues and protect the health and well-being of its citizens.

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