Mexico's Air Pollution: No Hay Fresco Air?

Mexico City's air pollution reached its peak in the 1980s and 1990s, with the city being named the world's most polluted city by the United Nations in 1992. The primary sources of air pollution were human activities such as the burning of fossil fuels in power plants, vehicle emissions, and industrial growth. The city's high altitude and topography, which is located in a basin surrounded by mountains, also contributed to the trapping of air pollutants. Since then, the Mexican government has implemented various policies and initiatives to combat air pollution, and by 2021, Mexico City had dropped to the 917th most polluted city in the world. However, air pollution still poses a significant threat to public health in Mexico, and the country is working towards improving air quality and reducing emissions.

Mexico City's air pollution was once the worst in the world

The Mexican government has actively combated this issue over the years, implementing plans like the "Hoy No Circula" ("Today, Don't Circulate") policy, introduced in 1989, which mandated that drivers could not use their vehicles one weekday per week. This policy has since been expanded to include Saturdays and further restrict vehicle usage to two days a week. All vehicles in Mexico City and the State of Mexico are required to undergo emissions testing every six months and are assigned a verification based on their performance.

The government also launched the Comprehensive Programme Against Air Pollution (PICCA) in 1990 and ProAire in 1995, both aimed at improving the air quality in the metropolitan area of Mexico City. Additionally, air quality management programs were implemented to reduce emissions by removing lead from gasoline, implementing catalytic converters, reducing sulphur content in diesel fuel, and substituting fuel oil with natural gas in industries and power plants.

These collective efforts have resulted in significant improvements. By 2021, Mexico City had dropped to the 917th most polluted city in the world, according to IQAir, a Swiss company that tracks global air quality. While Mexico City still exceeds the World Health Organization's guidelines for airborne particle concentration (PM 2.5), the progress made is undeniable.

However, air pollution remains a pressing issue in Mexico City. The country aims to tackle this problem by prioritizing public and active transport, such as electric transportation, cycling, and walking, to reduce emissions from vehicles, which are currently the main source of pollution within the city centre. Additionally, Mexico has set a goal of achieving zero deforestation by 2030 and is working to update and expand environmental health standards to align with the World Health Organization's guidelines.

Industrialisation, urbanisation, and lax regulations are key causes

Mexico City's air pollution reached its peak in the 1980s and 1990s, with the city being labelled the world's most polluted city by the United Nations in 1992. The primary causes of this severe air pollution were industrialisation, urbanisation, and lax regulations.

During the 20th century, Mexico City underwent rapid industrialisation and urbanisation, with the population of the metropolitan area, or Greater Mexico City, growing significantly from 3.1 million in the 1950s to 14 million in the 1980s. This rapid population growth, coupled with increased human activities, led to a substantial decline in air quality. The proliferation of vehicles, rapid industrial growth, and a population boom all contributed to the city's air pollution crisis.

Industrialisation brought thousands of migrants to Mexico City, resulting in a sharp increase in the population. This put a strain on the city's infrastructure and resources, leading to overcrowding and inadequate pollution control measures. Additionally, the city's topography, located in a basin surrounded by mountains, created a natural trap for air pollutants. The high altitude of the city, at 7382 feet above sea level, also contributed to the problem as it caused oxygen levels to be 25% lower, impacting the combustion of carbon-based fuels.

Lax and outdated regulatory frameworks have also played a significant role in Mexico's air pollution crisis. The lack of stringent regulations on factories, power plants, and oil refineries allowed highly polluting industries to operate without consequences. The government's failure to prioritise human health and generate timely information on air quality further exacerbated the situation.

The Mexican government has recognised the severity of the air pollution problem and has implemented various policies to address it. The "Hoy No Circula" policy, introduced in 1989, restricts vehicle circulation based on emissions testing results. Additionally, the government is working towards achieving zero deforestation by 2030 and promoting the use of public transport, active transport, and electric mobility systems to reduce emissions.

Air pollution is the eighth-largest cause of death in Mexico

Air pollution is a pressing issue in Mexico, causing about one in 17 (5.9%) of all deaths in the country. It is the eighth-largest cause of death, preceded by factors like diet, overweight, high blood pressure, alcohol and drug use, smoking, and lack of exercise. The air quality in Mexico City, the country's capital, has historically been extremely poor, earning it the title of the "most polluted city on the planet" by the United Nations in 1992.

The primary causes of air pollution in Mexico City are human activities such as burning fossil fuels in power plants, vehicle emissions, and industrial processes. The basin-like topography of the city, surrounded by mountains, traps air pollutants and contributes to the poor air quality. The city's high altitude, at 7382 feet above sea level, also plays a role in trapping pollutants and reducing oxygen levels by 25%.

The Mexican government has recognized the severity of the problem and implemented various policies to combat air pollution. The "Hoy No Circula" policy, introduced in 1989, requires vehicles in Mexico City and the state of Mexico to undergo emissions testing every six months. The government has also worked to close or relocate polluting factories, reformulate gasoline, and expand public transportation. These efforts have led to significant improvements in air quality, with Mexico City dropping to the 917th most polluted city in the world in 2021, according to IQAir.

Despite this progress, Mexico City's concentration of airborne particles (PM2.5) still exceeds the guidelines set by the World Health Organization (WHO). The most dangerous of these particles are those with a diameter of less than 2.5 thousandths of a millimetre (PM2.5), which can penetrate deep into the lungs. Reducing PM2.5 concentrations to the interim WHO target of 15µg/m3 could save at least 10,000 lives per year.

To further improve air quality and reduce the impact on public health, Mexico should prioritize public transportation, particularly electric transport, and active mobility options like cycling and walking. Additionally, the country should update and expand environmental health standards to align with WHO guidelines and regulate sectors like transportation and industry to reduce emissions.

The government has implemented policies to combat air pollution

One notable policy is the "Hoy No Circula" ("Today, Don't Circulate"), introduced in 1989. This policy requires all vehicles in Mexico City and the State of Mexico to undergo emissions testing every six months. Vehicles are then issued a verification, with "0" assigned to those meeting requirements, and "1" or "2" to underperforming vehicles. This policy aims to reduce vehicle emissions, which are a significant contributor to air pollution.

Another key strategy is the expansion of green areas and the promotion of active transport, such as cycling and walking. The government aims to prioritise public transport, particularly electric transport, over private vehicles to reduce transport emissions, the main cause of air pollution in the city centre. Mexico has also set a goal of achieving zero deforestation by 2030, addressing the role of industrial activities in air pollution.

To monitor air quality, Mexico uses the air-quality monitor system (IMECA), which measures the levels of six main pollutants: O3, PM10, PM2.5, CO, NO2, and SO2. IMECA provides a pollution index, indicating the level of pollution and associated health risks. This system helps authorities assess air quality and take protective actions.

While Mexico has made significant progress in reducing air pollution, dropping to the 917th most polluted city globally in 2021, airborne particles (PM 2.5) still exceed the World Health Organization's (WHO) guidelines. Reducing PM10 and ozone levels by 10% could save Mexico $760 million annually in medical and productivity losses.

To further improve air quality, Mexico should focus on transitioning households to cleaner fuels, such as LPG, and improving cookstoves, as indoor air pollution from cooking with firewood or charcoal severely impacts health in rural areas.

LPG stoves and improved cookstoves can reduce air pollution

Mexico City has long struggled with air pollution. In the 20th century, the city underwent rapid industrialization and urbanization, which led to a population boom. The UN declared Mexico City the most polluted city in the world in 1992. Air pollution in the city was described as so severe that birds were found dead from the toxicity of the air.

Today, the Mexican government has implemented various plans to reduce emission levels, including citizen participation, vehicular restrictions, and the expansion of green areas and bicycle accessibility. Air pollution is now the eighth-largest cause of death in the country, causing about 5.9% of all deaths.

One way to reduce air pollution is through the use of improved cookstoves. A study conducted in Nairobi, Kenya, found that improved stoves could reduce charcoal usage by 39%, saving households over $100 per year. Another study in India showed that LPG stoves had the lowest pollutant emission factors, with mean PM2.5 and CO emission factors over 90% lower than biomass stoves. LPG stoves can also reduce personal exposure to air pollution, as shown in a study conducted in Ghana.

LPG stoves are becoming increasingly popular, with around 50% of respondents in a study owning one, up from 20% in 2019. This increase is possibly due to government LPG subsidies. Subsidies for improved cookstoves, such as the Jikokoa, can cost-effectively reduce emissions, with a cost of only $4.9 per tCO2e.

By adopting improved cookstoves, air pollution can be reduced, leading to significant health benefits, especially for pregnant women and infants. However, to address the broader issue of air pollution, comprehensive solutions are needed, including tackling pollution from sources like traffic, waste burning, and industrial emissions.

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