Mexico City - Mexico's environment secretary estimated that a new procedure for verifying vehicle emissions would be in place "in two months or less," part of an effort to battle high air pollution levels in the capital's metropolitan area.

The goal is to ensure that the vehicles being driven every day in the Valley of Mexico have catalytic converters in good condition and thus emit fewer contaminating gases, Rafael Pacchiano told Radio Formula.

The idea is to incorporate into the verification process a machine "that connects to the vehicle's computer" and establishes whether it has a catalytic converter and "if it's in optimal condition." Automobiles of any model that are in compliance may be on the roads every day. Otherwise, they must have their catalytic converter repaired at a workshop and undergo the verification process again.

Those vehicles without a catalytic converter must undergo tests using a dynamometer, the technology currently used to measure contaminating emissions under simulated driving conditions. Based on the results, a determination will be made as to how many days per month that vehicle must be kept off the roads, the minister said.

The most important aspect of the new technology is that it cannot be manipulated, according to Pacchiano, who said that at present many non-compliant vehicles are wrongly verified due to corruption at emission verification centers.

The new procedure will be applied in the Megalopolis region, which includes Mexico City and metropolitan areas of the states of Mexico, Puebla, Tlaxcala, Morelos and Hidalgo, as well as in nine other states where the vehicle verification program already exists.

An estimated 40% of the roughly 6 million vehicles in the Valley of Mexico (Mexico City and the eastern half of the state of Mexico) lack a catalytic converter in good condition.

Automobiles in the Valley of Mexico account for more than 87% of nitrogen oxide emissions and 32 percent of volatile organic compounds, both of which are ozone precursors, authorities say.

Last Monday, the Environmental Commission for the Megalopolis, made up of the federal government and the federative entities in the region, activated an environmental emergency in the Valley of Mexico after "extremely poor" air quality was detected in some areas. That emergency measure, which included keeping cars with license plates ending in certain numbers off the roads and providing free public transportation in Mexico City, had not been imposed since 2002.

The measure was suspended Thursday after the air quality improved.