Air quality in Toluca de Lerdo

What is the current level of air pollution in Toluca?

Toluca, officially called Toluca de Lerdo, is the state capital of the State of Mexico as well as the seat of the Municipality of Toluca. It is approximately 63 kilometres from Mexico City. According to a census conducted in 2020, Toluca had an estimated population of 910,000 people. However, the total metropolitan area had 2.3 million inhabitants which made it the fifth most populous area in Mexico.

At the beginning of June 2021, Toluca was experiencing a period of “Moderate” air quality with a US AQI reading of 85. This United States Air Quality Index number is a globally used set of metrics supported by the World Health Organisation (WHO) and is used to compare the air quality in different cities throughout the world using comparable standards. It is calculated by using the levels of the six most commonly found pollutants. If figures are not all available, the figure is calculated using what data is available. In the case of Toluca, only PM2.5 was recorded and it was 28.2 µg/m³. The figure is quoted in micrograms/microns per cubic metre. At 28.2 µg/m³, it is almost 3 times higher than the WHO suggested maximum level of 10 µg/m³.

When the air quality is deemed to be “Moderate” the given advice is to remain inside as much as possible and close doors and windows to prevent the ingress of more polluted air. Those people who are more susceptible to poor quality air should avoid venturing outside until the quality improves. The table at the top of this page should help with that choice.

Is the air quality the same throughout the year in Toluca?

Air quality can be affected by many variables and therefore changes very often depending on atmospheric conditions. Looking back at the figures released by the Swiss air monitoring company, IQAir.com for 2020 it can readily be seen that Toluca was subject to “Moderate” air quality for the full 12 months without considerable variation. The figures fell between 12.1 and 35.4 µg/m³ for all 12 months. There were no records taken before 2020 so it is that figure of 27.1 µg/m³ that is used as a benchmark. However, this figure could be artificially lower than usual because of the restrictions brought into force due to the COVID-19 pandemic when the use of private vehicles was mainly prohibited because their drivers were furloughed and not required to commute each day and many manufacturing plants were told to cease production until further notice.

What are the sources of all this polluted air in Toluca?

According to the World Bank, air pollution kills nearly 33,000 people in Mexico every year. Almost 20,000 of these deaths are attributable to outdoor air pollution, mainly in towns and cities. The remaining 13,000 are from household air pollution, caused by cooking with wood and other solid fuels. This affects mainly rural communities.

In both urban and rural areas, the cause is the same: tiny particles in smoke that are breathed in and which can lead to chronic lung disease and acute respiratory infections, lung cancer, heart disease and strokes. This does not just affect Latin America, but is a global problem causing over 6 million annual deaths worldwide.

Air pollution in Mexico causes the death of 1 in 17 people and is the eighth largest cause of all deaths in the country. Over 16 million Mexicans cook with firewood or charcoal and many households use them as secondary fuels. Pollution levels in these rural households can be 6-15 times higher than in urban areas and this can severely damage health. For the person doing the cooking, concentrations of PM2.5 in the air breathed in are 11-26 times higher than the WHO recommendations.

Can anything be done to lower pollution levels in Toluca?

The biggest improvement to air quality would be to replace the solid-fuel household stoves with cleaner LPG models. But this costs money and sometimes it is money that the householder does not have and therefore, cannot afford to change.

In the early 1990s, Mexico City was described as the most polluted place on the entire planet. A title it has been trying to shake off for years. Despite many controls introduced because of this, Mexico still has big problems with its air quality. Large industrial growth, a boom in its population and an exponential rise in the number of vehicles using its roads, many of which are over 20 years old.

How does this poor air quality in Toluca affect human health?

Researchers have recently focused on health hazards posed by the most serious pollutants: PM10 and ozone. PM10 comes from various sources, including road construction and dust, diesel trucks and buses, forest fires, and the open-air burning of refuse. Both pollutants can irritate eyes, cause or aggravate respiratory and cardiovascular ailments, and lead to premature death.

Various experimental studies, as well as epidemiological studies in humans, have clearly indicated that exposure to pollutants in ambient air is associated with a wide range of adverse effects (acute and chronic), which affect the quality of life of the general population and of vulnerable groups, mainly children, pregnant women and the elderly, especially if they suffer from pre-existing respiratory diseases.

The most harmful particles for health are those 10 micrometres in diameter or less (PM10), which can penetrate and lodge deep inside the lungs. Chronic exposure to the particles increases the risk of developing heart and lung disease, as well as lung cancer.

There is a close quantitative relationship between exposure to high concentrations of small particles (PM10 and PM2.5) and increased daily and long-term mortality or morbidity. Conversely, when the concentrations of small and fine particles are reduced, the associated mortality also decreases, assuming that other factors remain unchanged.

Ozone is formed by the reaction with sunlight (photochemical) of pollutants such as nitrogen oxides (NOx) from emissions from vehicles or industry and volatile organic compounds (VOCs) emitted by vehicles, solvents and industry. . The highest ozone levels are recorded during periods of sunny weather.

Excess ozone in the air can cause serious adverse effects on human health. It can cause breathing problems, cause asthma, reduce lung function, and lead to lung disease. It is currently one of the atmospheric pollutants of greatest concern in Europe. Various European studies have revealed that daily mortality and mortality from heart disease increase by 0.3 per cent and 0.4 per cent respectively with an increase of 10 µg/m³ in ozone concentration.