MEXICO CITY -- At the prestigious American School here, teachers and students have braced themselves for a tough winter.
It is not violent snowstorms they fear. It's the smog.
In the last two years, indoor play spaces have been built for kindergarten and elementary students. And a few months ago, a new middle school opened. It is like a school in a bubble: completely sealed, air-conditioned and air-filtered.
Students there are breathing a lot easier.
"Last year, everybody was having headaches. People were missing school a lot," said eighth-grader Mike Eskenazi, who moved here three years ago from San Diego. "And now with this building, there isn't as much of that."
Air pollution is a year-round problem in this city of 20 million people, 4 million cars and 30,000 industries. Often the sky is shrouded by a brown haze that is a combination of ozone, lead, sulphur dioxide and dried fecal matter.
In the winter, when the summer rains end and heat forms an invisible cap sealing in the pollution, breathing becomes a crisis. Yesterday and most of last week, factories in the city were ordered to cut activities by 30 percent, people were advised to stay indoors during the afternoon and motorists were asked to leave their cars at home when air pollution reached danger levels.
Even the fittest felt tired after a short walk outside. Many suffered burning, watery eyes, nausea and headaches.
"Although officials at the Department of Health continue to affirm that no one is going to fall dead in the street from pollution, our bodies are in danger," said Homero Aridjis, president of the Group of 100, an environmental advocacy group. "We are very alarmed here."
Ozone levels in the city topped 200 for eight of nine recent days, with levels nearing 300 several afternoons between 1 p.m. and 3 p.m.
Mexico City measures ozone on a 500-point scale. Levels above 100, which occur almost daily in the city, are considered "unsatisfactory." Levels above 200 are considered "bad" and levels above 300 are dangerous.
In the United States, ozone is considered hazardous if its level in the air rises above .12 parts per million. Last year in Baltimore, there were 14 days where the ozone level was higher.
The levels are higher almost every day in Mexico City.
"This will mean a lot of illnesses in Mexico this winter," Mr. Aridjis said. "The problem is getting worse and worse."
Mexico City officials say there has been some relief. Over the last four years, they say, levels of lead, carbon monoxide and sulfur dioxide are below internationally accepted norms. Environmentalists charge that hose reports are false.
The Mexican government and the city have spent $2.8 billion combating the problem over the last three years.
Ecological police, known as "green patrols," roam the city, ticketing drivers of smoke-belching vehicles. Others are stationed at 11 checkpoints on highways leading into the city to screen for polluting cars.
The Electricity Commission has ordered a 25 percent cut in the activity of two thermoelectric generators in the metropolitan area. Petroleos Mexicanos, the state-owned fuel company, has created gasolines with fewer hydrocarbons.
A city program called "Day Without A Car" requires all drivers to keep their cars at home one day each week.
The office of the attorney general for the environment has stepped up helicopter flights to check for polluting factories, and on bad pollution days, some 30 inspection teams travel the city to make sure companies comply with the required cut in activity.
Still, the smog problem lingers. And the most nagging problem, city officials say, is ozone. Ozone, created when sunlight hits car exhausts and other emissions, can harm humans' respiratory systems.
Fernando Menendez, technical director of the Metropolitan Commission for the Prevention and Control of Contamination, said combating ozone is difficult because, each day, Mexico City residents burn 43 million liters of fuel for transportation, heat, and cooking. Geography makes the fight even tougher.
The city sits in a valley 7,000 feet above sea level. Fumes from the cars, industries and homes clog the thin air, and the surrounding mountains keep it trapped over the city.
"If we want radical solutions, we would stop selling fuels," Mr. Menendez quipped. "We can't live without fuel and industries, yet we want clean air."
It was two years ago that administrators at the American School decided to take drastic measures to protect their students from this constant menace.
"We held scientific hearings and learned that simply by sealing rooms and play areas, you immediately cut 70 percent of the problem," said David Ehrenreich, development director of the school. "You cut 70 percent of the ozone, 70 percent of the lead, 70 percent of the particulates."
Administrators are most proud of their new middle school. The structure, which cost $4.4 million, looks like a three-story shopping mall, with glass ceilings and classrooms placed where stores would be.
Instead of clearing the trees that were on the land, builders laid the floors around them.
"On a highly polluted day, you go from inside this building to the outside and you can feel the difference," said Mr. Ehrenreich.
"The kids are doing better scholastically for two reasons: They feel better physically, and they are proud of the facility.
"We have fewer discipline problems," he added. "There are not ** as many absences. They're just better kids."
A multipurpose room, where the air is cleaned by five filters, was built for kindergarten students. Operation of the filters costs some $25,000 a year, Mr. Ehrenreich said.
Mr. Ehrenreich also said that some 70 percent of the money and materials needed for the construction project was donated by parents, many of whom are corporate executives and foreign diplomats.
Without that kind of support, students at the American School would be left to suffer like millions of other public school students in the metropolitan area.
"Other schools are screwed," Mr. Ehrenreich said. "They don't have
the facilities we have, so their kids have to stay in class and they do not get exercise."
At a public school just north of Mexico City a few weeks ago, 28 students began to vomit and lose consciousness because of noxious fumes.
City officials have not determined the source of the fumes. The school is situated near several small factories and a Petroleos Mexicanos distribution facility.
"First they said it was a gas cloud, then they said it was fertilizers," said a maintenance man working at the school. "But in the end, they said they didn't know where it came from."
City officials told reporters that none of the students were seriously ill. A secretary in the school office, however, said 28 students were treated by the Red Cross. In an interview, she said only six of the students returned to school that afternoon. And five were hospitalized for three days.
"Their parents came and complained because their children were so sick," she said.
Ecologists throughout Mexico City complain that government measures to combat smog are too weak and say they suspect that official air quality reports are false.
"They should shut down the two thermoelectric plants and use electricity from 12 plants outside the valley," said Alfonso Cipres Villareal, president of the Mexican Ecological Movement. "And the 'Today I Don't Drive' program should be increased to two days.
"Thirdly," he added, "the government needs to provide portable toilets for the 7 million city residents who have no toilets and defecate outdoors."