Ozone out of control

• April 25, 2024

The concentration of ozone in the main cities of the country and in the Mexico City Metropolitan Area is worrisome. The latter has the highest pollutant emission rate per year, followed by Monterrey, Guadalajara and Ciudad Juárez. Why is it so complicated to keep such an annoying polluter under control?

A few decades ago, the air of the capital was compatible with health. However, from 1960, the development of the city accelerated the vehicular growth and the environment changed by factors such as the emission of pollutants, by the combustion of gasoline with high content of tetraethyl lead (additive that allows to increase its anti-knock quality) .

In the 1980s, the content of lead in gasolines was modified and measures were implemented to improve air quality. This allowed the gradual reduction of the toxic compound, he recalled. Humberto Bravo, from the Center for Atmospheric Sciences of the UNAM.

However, the researcher and his working group detected that the new gasolines improved with hydrocarbons (volatile organic compounds), in combination with the height and climate of the capital, originated an environmental problem that to date is a warning: the excessive concentration of ozone.

"Our air quality standard establishes that the concentration of ozone should not exceed 0.11 parts per million (ppm) in one hour a day, per year and for three consecutive years. When these levels are maintained, the air quality is good.

"In the capital, one thousand 200 hours were recorded in 1986; 20 years later it was reached 60 hours, and in 2009 about 140 days in which the norm was exceeded, "explained the specialist in environmental engineering.

Ozone control is possible, experiences in other cities show it. The city of Los Angeles, California, reached the highest levels of ozone in the 70s, therefore, modified the content of lead in gasolines. Today it remains at the permissible levels, he said.

In Mexico, he pointed out, adequate actions have been taken: we have a good air quality monitoring network, the IMECA index was established to inform the population, but road and environmental education has failed ".

The specialist stressed that the main adverse effects of high concentrations of ozone range from transient changes in lung function, impact on physical-athletic performance, increased incidence of respiratory diseases, lung diseases, allergies and eye symptoms.

Magazine The New England Journal of Medicine published in 2009 the results of a US study that evaluated the impact of ozone on respiratory health in a sample of the population for 18 years. According to the results, the risk of dying due to a respiratory disease is greater than 30% in metropolitan areas with high concentrations of ozone.

Therefore, the authorities recommend the population to limit the use of the car and refrain from outdoor activities when the levels of this and other pollutants soar, concluded Humberto Bravo.

Video Medicine: What Ozone Can and Cannot Do (April 2024).