Mexico's Air Pollution: Understanding The Root Causes

Mexico City has historically been known as one of the most polluted cities in the world. The air pollution in Mexico is caused by a combination of factors, including industrial growth, a sharp increase in population, vehicular emissions, wildfires, and the topography of the city. The city's high altitude and unique geography trap pollutants, leading to poor air quality. While there have been improvements in recent years, air pollution remains a significant issue, impacting the health and well-being of Mexicans and causing thousands of deaths annually.

Population growth and industrialisation

Mexico's population has grown significantly over the last few decades, with the population of Mexico City alone increasing from 3 million in 1950 to 20 million in 2015. This rapid population growth has been driven by industrialisation, which has brought thousands of migrants from all over the world in search of better opportunities. As a result of this industrial growth, Mexico City has emitted over 11,000 tons of waste material into the atmosphere every day. The economy has also boomed, leading to a proliferation of vehicles. The number of cars and light-duty trucks per 1000 residents in Mexico City increased from 124 in 1980 to 267 in 2010.

The combination of population growth and industrialisation has resulted in severely poor air quality in Mexico City. The city is located in a basin surrounded by mountains, which creates a "'bowl' effect" that traps pollutants and prevents their natural dispersion. This geographic characteristic, along with the city's high altitude, makes Mexico City particularly prone to poor air quality. The increase in population and economic activities has also led to a rise in the number of vehicles on the road, contributing to the air pollution problem.

In addition to the direct impact of industrial activities and vehicle emissions, population growth has also indirectly contributed to air pollution through deforestation and land use changes. Mexico lost 262,000 hectares of natural forest in 2018, with deforestation driven by the boom in crops such as soybeans, African palm, and avocado. While deforestation has various causes, it is estimated that around 90% of land use changes in Mexico are made illegally. The loss of forests and woodland contributes to air pollution and exacerbates the problem further.

To tackle the air pollution crisis in Mexico City, it is essential to address the root causes of population growth and industrialisation. This includes implementing policies to regulate industrial activities and vehicle emissions, promoting sustainable practices, and enforcing environmental protection regulations. Additionally, strengthening inspection and surveillance systems to prevent illegal land use changes and deforestation can help mitigate the impact of population growth on air quality.

Overall, the interplay between population growth and industrialisation has had a significant impact on air pollution in Mexico. Addressing this complex issue requires a comprehensive approach that considers both the direct and indirect contributors to air pollution and involves collaboration between various sectors and stakeholders.

Vehicle emissions

The topography of Mexico City also contributes to the issue of vehicle emissions. The city is located in a basin, which means that air pollutants tend to be trapped, and the "bowl" effect hinders the natural dispersion of pollutants. This results in pollutants lingering for longer than they would in a more open area.

The types of vehicles on the road are also a factor. In the 1980s, the cars were of poor quality and ran on very toxic fuel. Today, there are still a large number of older models with outdated emissions systems on the roads, and the inefficient public transport system further compounds the issue.

The Mexican government has implemented policies to address vehicle emissions, such as the "Hoy No Circula" policy, which was introduced in 1989 and requires all vehicles in Mexico City and the state of Mexico to undergo emissions testing every six months. However, the issue of vehicle emissions in Mexico is ongoing and remains a significant contributor to air pollution in the country.

Wildfires

The impact of wildfires on air quality and human health is significant. Wildfire smoke contains fine particulate matter (PM2.5) and ozone (O3), which can have detrimental effects on human health. PM2.5 refers to particles smaller than 2.5 thousandths of a millimetre, which can penetrate deep into the lungs and cause respiratory issues. In the case of the 2022 wildfires in New Mexico, it was estimated that the average daily wildfire smoke PM2.5 was 0.3 μg/m3, but with 1-hour maximums exceeding 120 μg/m3 in certain locations. These high concentrations of PM2.5 can lead to asthma and other respiratory problems, especially for individuals with pre-existing conditions.

Mexico's air pollution problem is exacerbated by a combination of factors, including industrial growth, a sharp increase in population, and the proliferation of vehicles. The country has experienced a significant population boom, with Mexico City's population growing from three million in 1950 to twenty million by 2015. This rapid urbanisation has resulted in increased industrial activities and a higher number of vehicles on the road, contributing to the overall air pollution levels.

To combat the air pollution crisis, the Mexican government has implemented various measures. They have introduced restrictions on less efficient cars, limiting their time on the road, and imposed vehicular restrictions when air quality deteriorates. Additionally, they are taking steps to increase green areas and improve bicycle accessibility. These efforts are aimed at reducing emission levels and improving the overall air quality in the country.

While wildfires are a significant contributor to air pollution in Mexico, it is important to recognise that the issue is complex and influenced by a range of factors. By addressing these various factors and implementing effective strategies, Mexico can work towards improving air quality and reducing the health risks associated with air pollution.

Deforestation

The primary cause of deforestation in Mexico is the change in land use for agriculture, livestock, and urban development. The expansion of crops such as soybeans, African palm, and avocado has led to the clearing of forests. Additionally, the increasing population requires more land for housing, buildings, and livestock grazing areas. It is estimated that Mexico lost 262,000 hectares of natural forest in 2018 due to these factors.

The consequences of deforestation in Mexico are far-reaching. Deforestation disrupts natural ecosystems and contributes to climate change by increasing carbon dioxide emissions. It also affects the livelihood of local communities, particularly those who depend on the forests for their traditional way of life. Deforestation can also lead to soil erosion, loss of biodiversity, and a decrease in water quality.

To address the issue of deforestation, Mexico has set a goal of achieving zero deforestation by 2030. This will require strengthening inspection and surveillance systems to prevent illegal land use changes, which currently account for around 90% of registered land use alterations. Additionally, promoting sustainable agricultural practices, such as crop rotation and agroforestry, can help reduce the need for deforestation.

Furthermore, initiatives such as reforestation projects, sustainable land management practices, and community education can play a vital role in mitigating the impacts of deforestation. By involving local communities in conservation efforts and providing alternative sources of income, Mexico can work towards preserving its remaining forests and restoring degraded areas.

Poorly ventilated households

The impact of these organic fuels is exacerbated by limited ventilation in many homes, a common issue in developing countries. As a result, household members, especially women and young children who spend most of their time indoors, are exposed to toxic pollutants at levels far exceeding World Health Organization (WHO) guidelines and national standards. The health consequences are severe, with high levels of indoor air pollution contributing to a significant number of annual deaths in Mexico and other developing countries.

The problem of indoor air pollution in Mexico is further compounded by the country's deforestation practices. In 2018, Mexico lost 262,000 hectares of natural forest, partly due to the expansion of crops such as soybeans, African palm, and avocado. While the government has set a goal of achieving zero deforestation by 2030, the current rate of deforestation continues to contribute to the indoor air pollution crisis by reducing the amount of natural ventilation and increasing the concentration of pollutants in the air.

To address this issue, there have been suggestions to transition households to Liquefied Petroleum Gas (LPG) as the primary fuel source. While this option is more expensive, it has the potential to significantly reduce indoor air pollution levels and save thousands of lives each year. Additionally, improved cookstoves with chimneys, such as the Eco-Stove, can reduce exposure to toxic pollutants by half while also reducing fuel costs. These solutions offer a more immediate and cost-effective approach to mitigating the impact of poorly ventilated households on Mexico's air quality.

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