Two power plants and a number of other industries in the metropolitan area have switched to the less-polluting natural gas. All cars produced in Mexico since 1991 have catalytic converters. Because many Mexicans can't afford new cars, however, only about 40 percent of vehicles are equipped with the pollution-reducing devices. Five years ago, officials decided to double the program whenever pollution levels skyrocket as they did earlier this year, pulling about 40 percent of old cars off the road during emergencies. Ozone peaked and remained for several hours at levels considered well above the healthy norm almost every day last year, Fernandez said.
Ozone irritates noses, throats and eyes.
People with colds, the flu or chronic respiratory problems suffer diminished lung capacity that leaves them gasping for air. When ozone is strong, illnesses are prolonged and doctors report a higher number of patients. I've had a cold at least two times a month recently and every day my eyes feel irritated. Headaches at this time of year are also more common. The other contaminant that still plagues Mexico City's air at dangerously high levels are suspended particles, the product of vehicle and industrial fuel emissions, dog droppings and soil erosion from barren open space that's devoid of trees or grass.