Preventing Air Pollution: Mexico City's Strategies For Cleaner Air

Mexico City's air pollution has been a major concern for decades, with the UN declaring it the most polluted city in the world in 1992. The city's high altitude, rapid population growth, industrialization, and proliferation of vehicles have all contributed to this issue. While Mexico City has seen improvements in air quality in recent years, dropping to the 917th most polluted city in the world in 2021, it still exceeds the World Health Organization's guidelines for airborne particle concentration. To address this issue, the Mexican government has implemented various measures, including requiring gasoline reformulation, closing or relocating polluting factories, and restricting vehicle usage. The city has also expanded public transportation, increased green areas, and promoted bicycle accessibility. However, air pollution remains a significant health, labor, and quality-of-life issue, particularly for lower-income residents.

Reduce vehicle emissions and traffic

Mexico City's air pollution is largely caused by vehicle emissions, with around 8 million cars travelling in the city every day, producing over 7,000 tons of pollution. This has been a major issue for decades, with the number of cars per resident doubling from 124 cars per 1000 residents in 1980 to 267 in 2010.

To reduce vehicle emissions and traffic, the Mexican government has implemented several policies. One of the most notable is the "Hoy No Circula" policy, which means "today, don't circulate". This policy prohibits drivers from using their cars one day a week. This has been in place since 1989 and has helped to reduce CO emissions by 86%, as well as reducing ozone and particulate matter.

Another policy is the requirement for all vehicles in Mexico City and the State of Mexico to undergo emissions testing every six months. Vehicles are then issued with a verification, with "0" assigned to those that meet the requirements, and "1" or "2" for underperforming vehicles. This helps to identify the most polluting vehicles and ensure they are not contributing further to the city's air pollution.

The government has also created incentives for the purchase of cleaner vehicles, and invested in public transport and bicycle infrastructure. This includes expanding bicycle accessibility and building bike lanes, as well as investing in public transport to encourage people to leave their cars at home.

These policies have helped to reduce air pollution in Mexico City, with the city dropping to 917th place in the world for air pollution in 2021. However, it is still important to continue implementing and improving policies to further reduce vehicle emissions and improve air quality in the city.

Improve fuel quality and reformulate gasoline

Mexico City has been working to improve air quality since the 1980s, when the city was labelled the most polluted in the world. One of the key strategies to achieve this has been to improve fuel quality and reformulate gasoline.

In the 1980s and 1990s, Mexico City's air pollution was at its peak, with ground-level ozone, carbon monoxide, sulphur dioxide, nitrogen dioxide, and airborne particles all at record levels. The city's high altitude of 7382 feet above sea level contributes to this, as oxygen levels are 25% lower, leading to incomplete combustion of carbon-based fuels. The proliferation of vehicles, rapid industrial growth, and a population boom also played a significant role. The vehicles from this era were of poor quality and used highly toxic fuel, which further exacerbated the problem.

To address these issues, the Mexican government implemented a range of policies and programs. One notable policy was "Hoy No Circula," introduced in 1989, which requires vehicles to undergo emissions testing every six months and restricts driving on certain days based on their performance. The government also implemented air quality management programs to reduce emissions, including removing lead from gasoline, reducing sulphur content in diesel transportation fuel, and substituting fuel oil in industry and power plants with natural gas. These measures have contributed to significant reductions in air pollutants over the years.

In addition to these efforts, the Mexico City government has continued to strengthen vehicular emissions control with advanced technologies and surveillance programs, such as Green inspectors and remote sensors, to identify high-emitting and non-compliant vehicles. They have also focused on improving fuel quality for both diesel and gasoline, although specific details on the methods employed are scarce. The use of fuel ethers, for example, has contributed to an 86% decrease in carbon monoxide, a 53% decrease in ozone, and a 32% decrease in particulate matter over a 20-year period.

While Mexico City has made considerable progress in improving air quality and is no longer ranked as the most polluted city in the world, there is still room for improvement. Ground-level ozone, for example, remains a concern, and the city needs more aggressive policies to address the root causes of air pollution.

Increase green spaces and vegetation

Mexico City has long struggled with air pollution, which has posed a serious threat to public health and the local economy. The city's unique geographical location—in a basin surrounded by mountains—has contributed to the issue, as air pollutants tend to be trapped in the area. The situation was further exacerbated by the industrialization and urbanization of the 20th century, which led to a population boom and an increase in human activities, resulting in severely poor air quality.

To address this issue, the Mexican government has implemented various measures to reduce emission levels and improve air quality. One strategy has been to increase green spaces and vegetation in the city. This approach not only helps mitigate particle resuspension but also provides multiple benefits to the urban environment and quality of life.

One way to increase green spaces is through the recovery, restoration, and expansion of urban parks and gardens. This can be done by converting abandoned or underutilized land into green spaces, as well as by incorporating more vegetation into existing public spaces, such as plazas, sidewalks, and road medians. Additionally, vertical gardens or green walls can be installed on buildings to increase vegetation without taking up valuable ground space.

Tree-planting programs can also play a crucial role in greening the city. Trees not only absorb pollutants but also provide shade, reducing the urban heat island effect. Native tree species that are adapted to the local climate, such as the Mexican cypress or the Mexican fan palm, should be prioritized to ensure their survival and maximize their ecological benefits.

Community gardens and urban farms can also be established to involve residents in the greening process. These spaces not only increase vegetation but also provide educational and recreational opportunities for locals, fostering a sense of community and a deeper connection to the environment. Furthermore, promoting green roofs, which involve planting vegetation on rooftops, can help absorb rainwater, reduce stormwater runoff, and provide insulation for buildings, contributing to a more sustainable city.

Reduce industrial emissions and close polluting factories

Mexico City's air pollution has been a cause for concern for its population and health officials for decades. The city's high altitude of 7382 feet above sea level results in oxygen levels that are 25% lower than at sea level. This, coupled with the fact that carbon-based fuels do not combust completely, has contributed to the poor air quality in the city. The topographical location of Mexico City, situated in a basin surrounded by mountains, also plays a role in trapping pollution. The rapid industrialization and population boom have further exacerbated the problem, with the city emitting over 11,000 tons of waste material into the atmosphere daily during the industrialization era.

To address the issue of industrial emissions and polluting factories, several actions can be taken:

Reduce Industrial Emissions:

• Transition to Cleaner Energy Sources: Mexico can encourage industries to adopt cleaner and renewable energy sources, such as solar, wind, or hydroelectric power. This will help reduce the reliance on carbon-intensive fossil fuels, which are major contributors to air pollution.
• Improve Industrial Processes: Implement best practices and technologies to minimize emissions during industrial processes. This includes investing in modern equipment and facilities that can capture and control pollutants before they are released into the atmosphere.
• Promote Energy Efficiency: Encourage industries to optimize their energy use and reduce waste. This can be achieved through energy audits, implementing energy management systems, and adopting energy-efficient technologies.
• Regulate and Monitor Emissions: Strengthen regulations and enforcement to ensure industries comply with emission standards. Regular monitoring and inspections can help identify excessive polluters and enforce penalties for non-compliance.

Close Polluting Factories:

• Identify and Target High-Polluting Industries: Conduct comprehensive assessments to identify the most polluting factories, particularly those emitting harmful substances like particulate matter, ozone, and toxic chemicals.
• Strict Enforcement of Environmental Regulations: Strengthen and enforce environmental laws and regulations to hold factories accountable for their emissions. Implement penalties, fines, or legal consequences for non-compliance.
• Relocate or Retrofit Factories: Consider relocating factories away from densely populated areas to reduce the direct impact on residents. Alternatively, provide incentives or assistance for factories to retrofit their facilities with pollution control technologies, helping them reduce emissions without necessarily closing down.
• Community Engagement and Pressure: Encourage local communities to organize and advocate for their health and well-being. Public pressure and engagement can be a powerful tool to influence factory closures or force industries to adopt cleaner practices.
• Economic Diversification: Support the development of cleaner industries and economic sectors to reduce the country's reliance on heavily polluting industries. This can include investing in renewable energy, sustainable agriculture, or service industries.

By implementing a combination of these strategies, Mexico City can effectively reduce industrial emissions and address the issue of polluting factories, contributing to improved air quality and the health and well-being of its residents.

Improve ventilation in households

Mexico City has long struggled with air pollution, which has posed a significant threat to public health and the local economy. The city's high altitude, geographical location, and industrialization have all contributed to the problem. While the air quality has improved in recent years, it still exceeds the World Health Organization's (WHO) guidelines for airborne particles (PM 2.5).

To address this issue, the Mexican government has implemented various measures, including vehicular restrictions, incentives for cleaner vehicles, investments in public transportation, and the development of bike lanes. Additionally, the government has worked to close or relocate polluting factories and reformulate gasoline. These efforts have led to notable reductions in carbon monoxide, ozone, and particulate matter levels.

One critical aspect of air pollution in Mexico City is indoor air quality. Households with inadequate ventilation, particularly those using solid fuels for cooking and heating, can experience exposure to toxic pollutants. This issue is prevalent in many developing countries and disproportionately affects women and children, who spend more time indoors.

To improve ventilation in households, here are some direct and instructive tips:

• Increase natural ventilation: Open windows and doors when the outdoor air quality is good. Create cross-ventilation by opening multiple windows or doors on opposite sides of the house to encourage airflow.
• Use exhaust fans: Install exhaust fans in kitchens and bathrooms to remove pollutants, odors, and moisture. Ensure proper ducting to the outdoors to prevent pollutants from recirculating inside.
• Opt for natural cleaning products: Choose cleaning products with natural ingredients and minimal chemical emissions. Avoid strong chemical cleaners, air fresheners, and scented candles, as these can release additional pollutants into the air.
• Be mindful of cooking methods: When cooking with a gas stove, ensure proper ventilation by using a range hood or opening a window. Avoid burning food, as it releases smoke and harmful pollutants. Consider using electric or induction cooktops, which produce less indoor air pollution than gas stoves.
• Maintain indoor plants: Certain indoor plants, such as peace lilies, spider plants, and aloe vera, can help improve air quality by absorbing carbon dioxide and releasing oxygen. They also act as natural air filters, reducing levels of common indoor air pollutants.
• Consider an air purifier: Invest in a high-quality air purifier with HEPA filters to remove fine particles and allergens from the air. Place it in the room where you spend the most time, such as the bedroom or living room.
• Regularly clean and vacuum: Dust and allergens can accumulate indoors, so regular cleaning and vacuuming can help improve air quality. Use microfiber cloths to trap and remove dust particles instead of spreading them around.
• Ventilate stored items: Properly store items that may emit pollutants, such as paint, cleaning products, and pesticides. Ensure these items are stored in well-ventilated areas to prevent the buildup of toxic fumes.
• Monitor indoor air quality: Use indoor air quality monitors to track levels of common pollutants like PM2.5, VOCs, and carbon dioxide. This awareness can help you identify problem areas and determine the effectiveness of your ventilation improvements.
• Seal and insulate: Seal gaps around doors and windows to prevent outdoor pollutants from easily entering the home. Proper insulation can also help regulate temperature and reduce the need for excessive heating or cooling, which can contribute to indoor air pollution.

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