Natural pollution from dust coming from the deserts, the ashes that spread after a volcanic eruption, or the burning of large extensions of fields affect air quality, which is added to the anthropogenic pollution produced by transportation, agriculture, and industries, says José Agustín García Reynoso, a researcher at UNAM's Institute of Atmospheric Sciences and Climate Change (ICAyCC).
According to the United Nations (UN), air pollution is the greatest environmental risk to human health and one of the leading preventable causes of death and disease in the world, responsible, as of 2016, for approximately 6.5 million premature deaths attributed to this phenomenon indoors and outdoors.
On its website, it stresses that in developing countries it disproportionately affects women, children, and the elderly, and in particular low-income populations who are often exposed to high levels of indoor and outdoor air pollution resulting from cooking and heating methods that use wood and kerosene.
The international agency considers air pollution to be a global problem that has far-reaching implications due to its vast spread and warns that, without aggressive intervention, the number of deaths caused by outdoor air pollution could increase by more than 50 percent by 2050.
The condition of the air has changed from the Earth's origin. "Before natural air had a lot of sulfur, then with the emergence of plants in the sea, they changed the chemical composition of the atmosphere from reducing to oxidizing, and a series of activities occurred when there was oxygen. This is also natural air, but during the growth of plants and animals there have been degradation processes of living organisms that have made the composition of the air not unique", explains García Reynoso.
The quality may not be acceptable for human health, even when the variations are of natural origin. The dust that reaches the atmosphere from the Sahara or the Altar Desert in Sonora has serious effects, and is of natural origin, but also cooperates in affecting the air.
On the occasion of the International Day of Clean Air for a Blue Sky, which is commemorated on September 7, García Reynoso affirms: "in Mexico City, in a range of 0 to 10, we are at level five of pollution. Although most of the time we are polluted, emissions vary due to the activities and this means that we do not have clean air".
The air quality in the capital of the Mexican Republic is not healthy, nor is it in most of the cities of the country and the world "because there are fresh emissions from vehicular activities, homes, businesses, and industries, depending on the type of city in question".
In the agricultural areas of Mexico, although there are no measurements, it is known that it is bad due to the burning of pastures and weeds; in the industrial areas due to emissions from factories and in the metropolis mainly due to transportation.
The World Health Organization (WHO) issues recommendations on suspended particles of the so-called "criteria pollutants", which are generated by various sources, which are: ozone, nitrogen dioxide, sulfur dioxide, carbon monoxide, and lead. "With them, the air quality is evaluated."
However, other types of substances are atmospheric toxins, which in the long term and at low concentrations also affect air quality. These include benzene, chromium, and formaldehyde.
Areas surrounding the capital city, such as Ecatepec, Tlalnepantla, and the Toluca Valley (all in the State of Mexico), can be considered high risk because they have additional sources of pollutants to the so-called "criteria" pollutants.
Some substances can be emitted only for a short period and cause immediate symptoms, such as eye and throat irritation, but the greatest risk is in the long term, as there are pollutants that cause cancer or, according to a study of their own about ten years ago, can reduce life expectancy by up to 60 days.
"The most important thing is that people are aware that the air is not clean. And not only in cities but also in agricultural and industrial areas," he stresses. García Reynoso considers that programs such as the "Today we don't circulate" are useful because of the use of catalytic converters and, above all, because the vehicle fleet is modernized.
Celebration of the UN
The UN determined that the 2022 theme for this ephemeris is "The Air We Share," which focuses on the transboundary nature of air pollution and underscores the need to take collective responsibility and action. It also highlights the need for immediate and strategic international and regional cooperation for more effective implementation of policies and mitigation measures to address air pollution.
We all breathe the same air, we have a common atmosphere that protects and sustains us. Pollution is a global problem against which we must act together, says the agency on its website.