Fouled Air a Major Pet Peeve for Mexico City

MEXICO CITY —  The hordes of mongrels scavenging the vast open-air garbage dumps on the eastern outskirts of Mexico City are part of this polluted capital’s dirtiest secret.

So is the handsome pet German shepherd preening in the tidy Esparsa Oteo park in the city center.

Statistics here show that Mexico City’s inner Federal District alone has more than 2 million dogs, which deposit at least 353 tons of waste a day. Few owners of the 580,000 registered pets bother to scoop up after their canines, bylaws notwithstanding. And hardly anyone cleans up after the city’s estimated 1.5 million stray mutts.

In a city with a 6-month-long dry season, the waste dries into dust that is then blown aloft. It combines with particles from factories, erosion from dried lake beds and hydrocarbons from car exhausts to form a vicious brew of particulates that darkens the skies and scars the lungs.

The picture gets uglier still: Mexico City has 13,000 street-corner food stands, catering to its millions of poor and working-class residents. The dog dust and other particulates settle on the tortillas, tamales and salsa being served up to customers at the open-air stands, feeding chronic intestinal miseries.

While scientists are still studying the role of dog dust in particulate pollution, it’s a sufficiently disgusting symbol of Mexico City’s vile air to have prompted a flurry of civic action programs in recent months.

Results have been modest. The problem of the dust is just one example of how much greater is the challenge for poor, disorganized societies to attack pollution than wealthy cities such as Los Angeles--especially when weak systems encourage scofflaws, and overwhelming human needs make problems such as stray dogs seem an afterthought.

The worst atmospheric hazard to public health in Mexico City has long been and still is ozone--the invisible, throat-searing gas formed by the sun’s reaction with nitrogen oxides and hydrocarbons. But small particulates are challenging ozone’s notoriety, not only in Mexico but in many developing countries--and even, to some extent, in Los Angeles.

A World Health Organization report in December 1997 described these lung-boring particulates as “the most important pollutant worldwide.” The problem is most severe in fast-industrializing societies such as China and India, especially where coal remains a basic energy source.

The dog dust is one of the nastiest organic particulates.

“We breathe it. We eat it. We irritate our lungs. We get sick with gastroenteritis. We are all exposed to this, especially children and older people,” Laura Elena Herrejon said with a shudder. “I never eat in the streets anymore.”

Herrejon, a tall and elegant business executive, is president of the Pro-Neighbor Movement, a year-old civic association that has made clean streets one of its goals--and dog poop its particular bugbear.

The most dangerous particulate matter is less than 10 microns in diameter, and thus called PM10. (One micron is a thousandth of a millimeter.) Not only does PM10 reduce visibility, it penetrates deep into the lungs.

A Mexico City government report said that many studies directly link increases in PM10 to higher death rates. The study said more than half the city’s residents are exposed each day to PM10 concentrations above the “unhealthy” threshold.

Readings of PM10 in the capital rose above the danger point on 52% of the days in 1998, up from 44% a year earlier--and almost zero in the early 1990s. Drought-fueled forest fires were one factor last year, and greater deforestation in recent years appears to have increased erosion on the edges of the Valley of Mexico. The nation’s economic rebound has its cost too, reviving output by brick factories and other PM10 generators north of the city.

Even after last year’s fires went out, PM10 levels soared to nearly twice the “unhealthy” norm in December, provoking the first pollution emergency ever called here because of particulates. This year, periodic spring rains have kept particulates well below 1998’s record levels, but authorities are watching to see what happens in the driest months of May and June.

The particulate scare arose even as the metropolitan area’s ozone problem was stabilizing--albeit at dangerous levels. Although ozone still exceeded the “unsatisfactory” level on 337 days last year, it no longer reaches the terrifying peaks of 1991 and 1992, when it sometimes rose to nearly four times the international health norm.

Indeed, Mexican authorities are proud of the results delivered by their antipollution program over the last decade. Measures include twice-yearly emission tests for all vehicles, the banning of lead and reduction of sulfur in gasoline and emergency programs in which as many as 50% of the cars must stay off the roads.

Officials argue that the capital’s air gets such notorious press because Mexico City measures its pollution far more precisely than comparable cities worldwide.

One of Nature’s Cruel Tricks

There’s no doubt that Mexico City is punished by nature, as well as its own excesses. Sitting in a mountain-ringed bowl at an elevation of 7,300 feet, the city is subject to frequent temperature inversions that trap pollutants. Winds are often light, and the altitude makes gasoline-burning engines 25% less efficient.

But human folly and flawed planning have loomed large ever since conqueror Hernando Cortes began draining the lakes that graced the Aztec capital, Tenochtitlan, in the 1520s. Just beyond the garbage mountains on the city’s eastern border, the now-dry bed of Lake Texcoco forms a vast dust bowl that is a major source of particulates in the valley. On one recent day, wind spouts stirred up mini-cyclones of brown dust.

While the lake bed was too poor for farming, it was acceptable for squatters, who began pouring into the valley during the 1950s. They built up areas like the immense eastern bedroom suburb of Netzahualcoyotl, now home to 3 million people in the state of Mexico, just beyond the Federal District’s border.

Of the nearly 18 million people in greater Mexico City, about 10 million live beyond the Federal District boundary but still within the valley--joined, no doubt, by millions more scraggly strays in addition to the 2 million dogs within the Federal District.

When a few residents founded the Pro-Neighbor Movement a year ago, they did so on the premise that, as the valley’s population exploded, the laws were increasingly flouted, making community life less safe and less pleasant, not least due to roaming, dirtying dogs.

“The laws are a joke--people know they will never be fined,” said Herrejon, the president of the group. “Before, our parks were places to bring children. Now you are sure to step in something.”

So Pro-Neighbor, which now counts 4,000 members, is trying to change people’s attitudes.

“We have to change our customs, reeducate ourselves,” Herrejon said. “We are saying, ‘Neighbor, it is your pet, make yourself responsible.’ ”

In February, Pro-Neighbor and the city’s Environment Department began putting up posters in city parks and handing out pamphlets. They show people how to clean up after their dogs, using plastic bags as gloves, and scooping up the waste tidily.

The group is trying to persuade companies to adopt parks and is working with pet food firms and dog owners associations. Herrejon is optimistic: “From crises, good things emerge.”

The often careless treatment of dogs infuriates dog lovers. One devotee, Ita Osorno, cares for 1,300 strays in her private dog shelter. She follows a strict no-kill policy and carries out 30 free sterilizations a day.

She complained that the media have “Satanized” dog waste as a pollution source, which will merely prompt more roundups and killings of strays rather than address the real problem of irresponsible owners who let dogs wander the streets and reproduce at random.

Parks Becoming Minefields

Judging by the piles of dog feces on a recent day in the square-block Esparsa Oteo park in the middle-class Del Valle section of the city, the challenge remains substantial. Two small children rolled on the grass near fresh excrement dropped by a German shepherd, with no owner of the animal in sight.

Park gardener Felipe Calete, who has worked for the city 27 years, said 15 to 20 stray dogs wander into the park daily. Some pet owners clean up after their dogs; some just let their pets out from nearby apartment buildings to use the park after dark.

“Many people don’t realize they are damaging their own families and children, who play here and get dirty or who eat from that tamale stand with the air so dirty,” Calete said. “I think the public attitude has gotten worse toward caring for the environment as the city has grown.”

In March, the downtown Benito Juarez district launched its own program, encouraging citizens to clean up after their pets but also dispatching municipal crews on bicycles to clean up after strays.

If the sanitation problem is serious in a well-to-do, in-town neighborhood, it is far worse in the vast poor belt surrounding the Federal District, especially the sprawling eastern and northern sides of the valley. Few areas are as foul as the Xochiaca strip, five square miles of garbage dumps and landfill along the Netzahualcoyotl border.

Netzahualcoyotl was a poet king of the pre-Columbian Aztec city of Texcoco; the modern queen of the garbage mountain is Maria Luisa Alanis Robles, who has ruled one of the largest garbage fiefdoms for 17 years. She controls the gate where horse-drawn carts bring a steady flow of trash from adjacent Netzahualcoyotl. The 40 or so families within her section live in shacks atop the trash, and scavenge a living by sorting through it for recyclable materials such as soda cans.

Looking toward several dogs climbing over the garbage, Alanis snorted: “They belong to nobody; they scrounge for tortillas. There are dogs that are sick, old; they defecate anywhere. Lots of puppies are left here along the fence by families who don’t want them, and the dogs grow up and spend their whole lives here.”

Juan Reyes, head of Netzahualcoyotl’s dog pound, said 20 to 40 strays are rounded up daily and taken to the pound. “If no one claims them in 72 hours, they are sacrificed,” he said. No more than two are reclaimed a day.

The criteria for declaring pollution emergencies were tightened last year. Using a California-style scale on which 100 points is the “unhealthy” level, the trigger for an ozone emergency was reduced from 250 points to 240.

And reflecting increased concern about small particulates, the new rules for the first time set a threshold for PM10 as well. The valley’s emergency program kicks in when small particulates reach 175 on the scale, as they did in May and again in December.

For her part, garbage dump leader Alanis sees a brighter future.

“My vision for this place is that, once it is filled in, it will go from a garbage dump to an ecological park,” she said, “for the good of the community--so the children can play here.”