Ecologists Alarmed as Mexico City’s Smog Season Could Be Worst Yet : Environment: High levels of contaminants are saturating the air in the 7,000-foot-high capital.

A quivering red sun rose over the world’s largest city Monday, but rather than inspiring joy, dawn brought to mind a hangover-ridden morning-after as muted sunlight forced its way through a cloud of gaseous haze.

The so-called “smog season” has hit Mexico City with a particular vengeance this year, and ecologists are warning that dangerously high levels of contaminants are saturating the oxygen-thin air over this 7,000-foot-high capital.

Windless, colder-than-usual weather is producing daily thermal inversions that prevent the gray veil from dispersing. The ecologists warn that this may be Mexico’s worst winter if the government does not take stronger action soon to control emissions from automobiles and industry.

“This is alarming. It is very serious,” said Luis Manuel Guerra, head of the Autonomous Institute of Ecological Research. “If this were Los Angeles or Denver, we would be in an alarm situation with the concentrations of pollutants that we have now.”

While publicly downplaying the problem, government officials did invoke the first stage of an emergency Environmental Contingency Plan over the weekend to reduce operations by 30% at dozens of industrial plants. Officials also restricted operations at the 18 de Marzo oil refinery in the heart of Mexico City’s urban sprawl, saying that a mechanical failure had caused it to spew toxic sulfur dioxide.

The plant resumed full operations on Monday after the problem was fixed, according to Sergio Reyes Lujan, assistant secretary of ecology and urban development. He said the state-owned Petroleos Mexicanos oil company, known as Pemex, would be heavily fined for the mess.

Guerra said that his air samples show levels of lead, carbon monoxide and ozone two and three times higher than the maximum acceptable under Mexico’s air quality standards.

“For example, the maximum ozone level is 0.11 parts per million for one hour once a year. We have surpassed that 1,000 hours this year . . . over 300 days,” Guerra said. Last Thursday, he said, the ozone measured .30 parts per million--nearly three times the maximum.

Last year, the government initiated a program called “Today, Don’t Drive,” requiring motorists to leave their cars home one day a week. Although the program initially produced results, ecologists say its effect has been neutralized by the estimated 275,000 automobiles newly registered in Mexico City during 1990.

The government also began requiring semiannual exhaust tests on the estimated 3 million cars in the capital. But critics say that corruption has diluted that program, too.

“You can show up with the oldest, dirtiest car, but if you pay (a bribe), you pass,” said Homero Aridjis, president of Mexico’s Group of 100, an organization of leading intellectuals and environmentalists.

Aridjis and Guerra, the most outspoken activists on the smog issue, say the government should adopt a more flexible contingency plan that goes into effect before pollution reaches such extreme levels. Industries should be forced to clean up their emissions, and much of the public transportation should be converted to butane and propane gas.

“In the medium and long term, industries should leave the city. The only thing that can salvage the city is industrial and economic decentralization,” Aridjis said.

He noted that the government announced a 21-step plan to fight pollution in 1987 and a program of 100 actions to improve air quality in the capital in 1988, neither of which were completed.

The environmentalists are urging the government to repeat a measure taken in 1989 prolonging Christmas vacation in public schools until February, when the weather warms a bit and winds pick up.

Doctors contacted Monday said they are seeing a dramatic increase in respiratory ailments, particularly among children, but lack the data to determine whether it is due to a virus, the cold weather or pollutants.

Dr. Carlos Javier Arnaiz Toldeo, past president of the Mexican Pediatrics Assn., said 75% of the patients he sees now are suffering respiratory problems. That is about 10% above last winter.

“Definitely, during this period of cold temperatures when the layer of contamination is (closer to the ground) for longer periods of time, respiratory problems increase, and especially in children,” Arnaiz said.

Many residents of Mexico City are complaining of chronic itching eyes, headaches, irritability and fatigue. El Universal newspaper reported that the Health Ministry registered 140,000 cases of respiratory illnesses in the first weeks of December.

Reyes Lujan of the Ministry of Ecology and Urban Development said such ailments are “normal illnesses in the winter season.” He admitted that ozone is still a serious problem in the capital, but insisted that lead and sulfur dioxide in the air are down sharply.

Reyes Lujan said the emergency plan was put into effect over the weekend because the oil refinery was emitting sulfur dioxide, but Aridjis said the government’s own measurements showed unacceptable levels of ozone and carbon monoxide as well for Friday through Sunday. It was the fourth time the plan has ever been implemented.

“All of the contaminants reached extremely dangerous levels, some two and three times above the acceptable level,” Aridjis said.

“This winter is very bad,” added Guerra. “If it continues, it could become the worst winter yet.”