A phase 1 environmental alert activated in Mexico City Monday due to high levels of ozone pollution was lifted at 8 p.m. Wednesday.

The Environmental Commission of the Megalopolis (CAMe) said that concentrations of ozone had declined due to a reduction in the intensity of a high-pressure system over the Valley of Mexico.

That development allowed for greater ventilation and assisted in the dispersion of ozone, a contaminant that can cause and exacerbate a range of respiratory conditions.

CAMe warned that in “ozone season” – the period of warm and dry weather before the annual rainy season – “the intensity and movement of high-pressure meteorological systems continually change, which could cause new increases in the concentration of ozone.”

The commission also said that other weather conditions can encourage the accumulation of ozone, which develops as a result of nitrogen oxide and hydrocarbon emissions. It consequently called on residents of the greater Mexico City metropolitan area to avoid using their cars as much as possible.

A reduction in the number of vehicles on the road will minimize the risk of air quality deteriorating to bad or very bad on Thursday, CAMe said, noting that “adverse conditions for the dispersion of contaminants” will prevail.

It noted that a maximum temperature of 29 C was forecast for the capital on Thursday as well as “high solar radiation,” which aids the formation of ozone.

In addition to calling on Mexico City residents to reduce vehicle use, CAMe advised capitalinos to avoid the use of products that contain solvents such as aerosols and paint, to repair any gas leaks in their home and to reduce the use of gas by taking short showers and using pots with lids for cooking.

With reports from Milenio