Mexico City's Air Pollution: Why It's Getting Worse

Mexico City's air pollution problem is caused by a combination of factors, including population growth, increasing motorization and industrial activities, geographical location, and insufficient environmental policies. The city's basin-like topography, surrounded by mountains, creates a bowl effect that traps pollutants and prevents their natural dispersion. While there have been improvements since the 1980s and 1990s, when air pollution was at its peak, Mexico City still faces challenges in reducing emissions and improving air quality. Wildfires, climate change, and the lack of a concrete decarbonization plan by the Mexican federal government also contribute to the persistence of air pollution in the city.

Population growth, increasing motorization, industrialization, and urbanization

Mexico City's air pollution has been a concern for decades, and it is the eighth leading cause of death in the country. Population growth, increasing motorization, industrialization, and urbanization have all contributed to this issue.

Population Growth

From 1950 to 2015, the population of Mexico City increased from three million to twenty million. This population boom was largely due to migrants seeking better opportunities. This rapid growth has led to a higher demand for housing, infrastructure, and resources, which has put pressure on the environment and contributed to the air pollution problem.

Increasing Motorization

The proliferation of vehicles in Mexico City is a significant contributor to air pollution. In 1980, there were 124 cars and light-duty trucks per 1000 residents, and by 2010, this number had increased to 267. The burning of fossil fuels in vehicles releases carbon monoxide, a harmful gas, into the atmosphere. In addition, the lengthening of automobile trips due to urban sprawl further increases emissions and air pollution.

Industrialization

Industrial growth has led to the emission of over 11,000 tons of waste material into the atmosphere daily. Industrial activities emit primary pollutants such as carbon monoxide and sulfur dioxide, as well as secondary pollutants like ozone and sulfate, which are formed through chemical reactions. In addition, carbon-based fuels used in industries do not combust completely, further contributing to air pollution.

Urbanization

The urbanization of Mexico City has led to a lack of green areas, which contributes to the impoverishment of the urban environment and quality of life. It also leads to the proliferation of heat islands and the resuspension of particles, worsening air quality.

Geography and topography

Mexico City's geography and topography play a significant role in exacerbating its air pollution problem. The city is situated in a basin surrounded by mountains, creating a bowl-like effect that traps pollutants and hinders their natural dispersion. This unique geographical feature has historically contributed to the city's reputation for thick smog and hazy skylines.

The topography of Mexico City, with its high altitude and enclosed basin, makes it particularly susceptible to the accumulation of pollutants. The mountains surrounding the city act as a natural barrier, trapping harmful particles and preventing their dispersal. This phenomenon is further intensified by the city's elevation, which, combined with the basin-like shape of the surrounding land, creates a container-like effect.

Wildfires, which have been increasingly influenced by climate change, also play a significant role in degrading air quality in Mexico City. The smoke and particles generated by these fires, combined with other environmental conditions such as above-average temperatures, low rainfall, and prolonged drought, worsen the situation. The topographical location of the city, with its bowl-shaped basin, traps these pollutants, making it challenging for them to dissipate.

Additionally, the intense solar radiation in Mexico City further contributes to the air pollution problem. The interaction of solar radiation with other factors, such as volatile organic compounds (VOCs) and nitrogen oxides (NOx), accelerates the formation of ground-level ozone, a significant air pollutant in the city. The unique geographical characteristics of the city, including its mountainous surroundings and basin-like shape, further trap the ozone and other pollutants, exacerbating the issue.

To address the air pollution crisis in Mexico City, it is crucial to consider both short-term and long-term solutions that take into account the city's unique geographical and topographical features. While the "Hoy No Circula" policy, which restricts vehicle circulation on certain days, has been implemented to reduce vehicle emissions, more comprehensive strategies may be required to mitigate the impact of the city's geography and topography on air quality.

Lack of aggressive policies and concrete decarbonization plans

Mexico City's air pollution problem is exacerbated by a lack of aggressive policies and concrete decarbonization plans. While the city has made significant progress since the 1980s and 1990s, when air pollution was at its worst, more needs to be done to address the root causes of the problem.

One of the main issues is the lack of a net zero target and a concrete decarbonization plan at the federal level. Despite ratifying the Paris Agreement, Mexico has yet to set a net zero goal. The Climate Action Tracker (CAT) has criticized the country's lack of ambition in combating climate change, citing the absence of a concrete plan to reduce carbon emissions. This lack of federal leadership trickles down to the local level, where environmental policies often lack the necessary financial and political support from the central government.

The Mexican government's approach to GHG-related policies reflects its attitude towards air pollution. While not directly linked, both issues share the same sources. The government's lack of urgency in addressing GHG emissions suggests a similar lack of urgency in tackling air pollution.

Additionally, Mexico City's unique geography contributes to the air pollution problem, and more aggressive policies are needed to mitigate this issue. The city's location in a basin surrounded by mountains creates a "bowl" effect that traps pollutants, preventing their natural dispersion. While this is a natural challenge, more could be done to address it through policies and urban planning. For example, the city could prioritize the expansion of green areas, the modernization of forest fire prevention programs, and the implementation of a metropolitan environmental sustainability agenda that incorporates an ecosystem-based vision.

Furthermore, the city's vehicular emissions are a significant contributor to air pollution. The ever-increasing number of cars, especially older models with outdated emissions systems, releases harmful pollutants into the atmosphere. Inefficient public transport systems further compound this issue. While there have been some policies implemented, such as emissions testing for vehicles, more aggressive measures are needed to reduce the number of vehicles on the road and promote sustainable alternatives.

Lastly, the lack of aggressive policies to reduce emissions from industrial areas surrounding and within Mexico City contributes to the problem. Chemicals from manufacturing plants and emissions from power stations continue to be released unchecked, posing severe environmental and health hazards. While regulations exist, compliance and modernization remain challenges. More stringent policies and enforcement mechanisms are needed to address this issue effectively.

Wildfires and climate change

Mexico City has historically struggled with air pollution. In the 1980s and 1990s, the air quality in Mexico City was so poor that birds were found dead due to the toxicity of the air. While the air quality has improved since then, the city still faces significant pollution problems.

One of the factors contributing to the air pollution problem in Mexico City is wildfires. In 2019, the Ministry of Environment and Natural Resources reported at least 66 fires in the capital and 130 in the State of Mexico, which borders Mexico City. The smoke and particles from these fires, combined with other environmental conditions such as above-average temperatures, low rainfall, prolonged drought, high solar radiation, and the city's topographical location in a basin surrounded by mountains, contributed to the worsening air quality.

Climate change has exacerbated the frequency, scale, and intensity of wildfires in Mexico, making them more challenging to control. The country has experienced longer and more intense wildfire seasons, with fires occurring in places where they previously did not. Climate change has also contributed to drought conditions, reducing water in the vegetation and creating highly fire-prone landscapes.

In addition to wildfires, other factors contributing to the air pollution problem in Mexico City include population growth, increasing motorization and industrial activities, and a lack of green spaces. The city's constrained basin and intense solar radiation further contribute to the concentration of pollutants.

To address the air pollution problem, the Mexican government has implemented various programs to reduce emissions, such as removing lead from gasoline, promoting the use of catalytic converters, and reducing the sulphur content in diesel fuel. However, Mexico has yet to set a net-zero target, and its current environmental policies lack sufficient financial and political backing from the federal government.

The impact of climate change and wildfires on Mexico City's air quality highlights the urgent need for comprehensive and well-supported environmental policies to mitigate the effects of these challenges.

Vehicular emissions and inefficient public transport

Mexico City has long struggled with air pollution, which reached its peak in the 1980s and 1990s. The city's high altitude and mountainous surroundings are natural factors that exacerbate the problem. The proliferation of vehicles and the burning of fossil fuels in power plants and vehicles are significant contributors to air pollution.

Vehicle emissions are a major source of air pollution in Mexico City. In the 1980s, there were about 124 cars per 1,000 residents, and while this may not seem high, these cars were of poor quality and used highly toxic fuel. The doubling of the vehicle fleet from 1992 to 2012 significantly impacted air quality. Today, vehicle exhaust is the source of 75% of emissions in the city.

The Mexican government has implemented various policies and programs to reduce vehicular emissions, including emissions testing for all vehicles, which are then assigned a verification label. Underperforming vehicles are prohibited from being driven on certain weekdays and Saturdays. However, the effectiveness of such policies has been questioned, as people often choose to buy another car to drive on restricted days instead of using public transportation.

Mexico City's public transportation system has been described as inefficient, and there is a lack of aggressive policies to combat the root causes of air pollution. The city has expanded its public transportation network, but there is a need to improve the overall efficiency of the system and increase the energy efficiency of motor vehicles. The use of fuel ethers and the implementation of low-sulphur standards have helped reduce carbon monoxide, ozone, and particulate matter levels.

The promotion of non-polluting means of transport, such as electric public transportation, cycling, and walking, is essential to reducing emissions. The government has also implemented programs to regulate fuel consumption and promote cleaner and more efficient energy sources. However, the lack of financial and political backing from the federal government for local environmental policies remains a challenge.

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