The Metropolitan Autonomous University of Mexico (UAM) is studying the quantities and composition of the particulates measuring around 2.5 micrometers that circulate in the atmosphere of the Mexican capital. Because of their size, the tiny particles can penetrate the depths of the human lung, contributing to emphysema and cancer, say medical experts.

The poor air quality in Mexico City and its surroundings, home to 20 million people, leads to some 35,000 deaths each year, according to studies by the municipal government.

The principal threats are the emissions produced by transport and industry, as well as other sources, which reach 2.5 million tons of particulate matter annually.

But the current study does not involve the even finer particles, which can contain aluminum, lead, cadmium and silica.

The investigation “will contribute towards defining future standards for regulating emissions,” says Violeta Mugica, researcher at the UAM's Department of Basic Sciences.