Qualité de l’air à Tlalpan

What is the current level of air pollution in Tlalpan?

Tlalpan is one of the 16 administrative boroughs of Mexico City. Tlalpan is the largest of Mexico City's sixteen boroughs, and vastly larger than the traditional village of Tlalpan. It has an area of approximately 310 km² and accounts for 20.6 per cent of Mexico City and a total population of 650,567 inhabitants.

During September 2021, Tlalpan was going through a period of air quality classed as being “Unhealthy for sensitive groups” with a US AQI reading of 122. This United States Air Quality Index number is calculated by collecting data from the six most prolific air pollutants which are usually; nitrogen dioxide, sulphur dioxide, ozone, carbon monoxide and both sizes of particulate matter, which are PM2.5 and PM10. This can then be used in comparison when studying other cities from any location. If not all six figures are available, a figure can still be calculated by using what data is available. There were five pollutants recorded for Tlalpan which were; PM2.5 - 44 µg/m³, PM10 - 76.6 µg/m³, ozone (O₃) - 0 µg/m³, nitrogen dioxide (NO₂) - 0 µg/m³ and sulphur dioxide (SO₂) - 0 µg/m³. The level of PM2.5 is over four times above the recommended target figure of 10 µg/m³ which was suggested by the World Health Organisation (WHO).

With air pollution at this level, you would be advised to stay indoors as much as possible, closing all doors and windows to prevent the ingress of more polluted air. The operation of an air purifier would be beneficial but ensure the air intake will recirculate the air and not keep sucking in the polluted air from outside. Those who are sensitive to poor air quality should try to avoid going outside unless absolutely necessary and even then limit the time of exposure and always wear a good quality mask.

Does the level of air pollution vary much throughout the year in Tlalpan?

Air quality can and is affected by many variables such as atmospheric and meteorological conditions. In 2020, for the months of January, November and March through until the end of July, Tlalpan was experiencing a period of “Moderate” air quality with figures between 12.1 and 35.4 µg/m³. The months of February and December returned “Good” quality air with a figure of 12.0 µg/m³ for each month. The best air quality was enjoyed from August until October with figures below the WHO target figure of 10 µg/m³ or less. The respective figures were 8.1, 9.2 and 8.9 µg/m³. Overall, the best quality air was had in August and the worst quality air was in May.

Historically, records regarding air pollution were first kept in 2019 when the figure was noted to be 18.4 µg/m³. The following year saw an improvement with an annual average of 12.3 µg/m³. This figure coincided with the COVID-19 pandemic when many vehicles were no longer in daily use in an attempt to stop the spread of the virus. Many factories and non-essential production units were also required to close which removed their emissions from the atmosphere and therefore, most cities revealed very good figures for air quality.

Where does the polluted air come from in Tlalpan?

According to data, an average of 5 million 400 thousand cars pass through the Mexican capital every day. The extremely high population concentration, coupled with the constant use of private vehicles, make pollution by suspended particles a constant problem. Due to human activity, the composition of the natural air in Mexico City is modified. Transportation, industry and power generation produce substances that significantly deteriorate the atmosphere, and can have negative impacts on the health of the inhabitants, particularly at the respiratory and cardiovascular level.

The main source responsible for this deterioration are the gases produced by the burning of fossil fuels for transport. This condition is intensified since the city is crowned by volcanoes, which impede the passage of wind currents that could clear the space of suspended particles, which are categorised at the state level by their size and origin.

What can be done to reduce air pollution in Tlalpan?

From 2019 to 2024, the government will seek to increase the amount of recycling from 1,900 to 3,200 tons, as well as increase the compost from 1,400 to 2,250 tons. Through the use of new technologies, it will seek to process 2,250 tons of waste. The most relevant projects are a new recycling plant in Vallejo and a composting plant in Central de Abastos.

The mobility axis will concentrate the largest amount of resources with 100,000 million pesos for:

• Increase the trolleybus network and 500 new units by 2024.
• 800 new RTP units with particle trap.
• 1,000 particle traps on existing RTP and Metrobús buses.
• A zero or low emission Metrobús line.
• Expansion of Line 12 with federal resources and 30 new trains for the network.
• Intervention of the Xochimilco-Tasqueña Light Train tracks.

In addition, it will begin the integration of the collection of public transport through a single card, including the RTP, Trolleybus and concessional transport. With the proceeds, a fund will be created for the renovation of 70% of the concessional buses.

What are the detrimental effects of air pollution in Tlalpan on our health?

Breathing dirty air affects more than just the lungs and causes more than premature death. Air pollution affects almost every organ in the body. A recent study shows that air pollution contributes to many ills, from diabetes and dementia to fertility problems and childhood leukaemia.

Dirty air contains invisible material. Inhaling soot or smoke with particulate matter, often referred to by its size in micrometres, PM10, PM2.5, and PM1, blackens the lungs, causes respiratory and heart problems, and diseases such as asthma and cancer. Some PM10s are visible as a cloud, and like PM2.5 they affect visibility by scattering and absorbing light, but it takes a microscope to see PM2.5 and an electron microscope to detect ultrafine particles. The smaller the particle, the deeper it can go into the lungs, along with the chemicals it is made of. This type of air pollution arises from the incomplete combustion of wood and plants, as well as fossil fuel, dust, and combinations of other pollutants from various sources.