Monday, April 05, 2010

Environmental policies that work - Reducing air pollution in Mexico City

Following up the earlier post about long-term reductions in air pollution in the US ... I am pleasantly surprised (perhaps I should say pleasantly astonished) to discover that since the 1990s they have been able to achieve a dramatic improvement of air quality in (believe it or not) Mexico City.
This megalopolis once had the world's worst air, with skies so poisonous that birds dropped dead in flight. Today, efforts to clean the smog are showing visible progress, revealing stunning views of snow-capped volcanoes -- and offering a model for the developing world.
"Model" is right. If it can be done there, it can be done anywhere.
"We have seen a lot of improvement. It is very clear," said Luiz Augusto Cassanha Galvao, a senior environmental officer at the Pan-American Health Organization. "On a scale of one to 10, they were at 10, and now they're at five." [....]

In 1992, the United Nations declared Mexico City the most polluted on the planet. High ozone levels were thought to cause 1,000 deaths and 35,000 hospitalizations a year. Thermal inversions held a toxic blanket of dirty air over a grimy city that seemed to embody the apocalyptic "Makesicko City" of the fiction of Mexican author Carlos Fuentes.

Mexico was forced to act. It replaced the city's soot-belching old cars, removed lead from gasoline, embraced natural gas, expanded public transportation, and relocated refineries and factories.

Change was gradual, but the pace has quickened in recent years.

The presence of lead in the air has dropped by 90 percent since 1990. Suspended particles -- pieces of dust, soot or chemicals that lodge in lungs and cause asthma, emphysema or cancer -- have been cut 70 percent. Carbon monoxide and other pollutants also have been drastically reduced. [....]

Ozone levels have dropped 75 percent since 1992, but they still exceeded international standards for a total of 530 hours last year. [....]

"If the government decides to do something about it, it can be done," said Nobel Prize-winning air quality expert Mario Molina. "There's really no excuse not to do more." [....]

Mexico City's geography adds to the problem; the city of more than 20 million is cradled in a 7,300-foot-high bowl, surrounded by peaks higher than 17,000 feet that trap pollutants.

But experts say many places overcame similar challenges. European cities, for example, halved pollution in recent decades by dramatically reducing coal fuel.

"Simple measures that enormously reduce pollution are feasible, and they are not expensive," said Michal Krzyzanowski, an air quality adviser for the World Health Organization.

"It is not the destiny of mankind to live in polluted cities."
Perhaps not.

The passages quoted above come from a Washington Post story to which I was alerted by Michael O'Hare at The Reality-Based Community. His post celebrating the transformation of Mexico city's atmosphere from deadly and intolerable to merely unsatisfactory and still improving is worth reading (below)--not least for the before-and-after pictures. As he says:
The improvement in every quality indicator of air quality in an enormous city located in one of the worst places for air pollution persistence is an inspiration.
Yours for effective environmental sanity,
Jeff Weintraub
Michael O'Hare (@ The Reality-Based Community)
March 31, 2010
Environmental policy that works

J. M. Velasco, Valle de Mexico 1892

This is what the Valley of Mexico looked like at the turn of the 20th century. When I came across a couple of paintings of this view by José Maria Velasco, a near-contemporary of the Hudson River School artists of the US, in the Museo Nacional de Arte, I was close to tears, having walked into the building from contemporary Mexico City. Has there ever been a more complete devastation of a natural paradise, short of flooding a valley with a dam, or dumping a West Virginia mountaintop into the river below it to get some coal out?

In less than a hundred years an idyllic mountain valley surrounded by volcanoes had turned into the eighth largest city in the world stifling in a pool of toxic, opaque air pollution:

Photo: Alfredo Cottin

Mexico City hasn’t got its lake back, and is still sinking because of pumping groundwater, and it remains one of the most pedestrian-hostile cities in the world, but not having been there for almost a decade, I loved this story: you can see across it again, and breathing isn’t a constant insult to lungs.


The improvement in every quality indicator of air quality in an enormous city located in one of the worst places for air pollution persistence is an inspiration. No, the economy didn’t collapse under the crushing weight of brutal regulation: the cleanup wasn’t free but it’s such a bargain, not just in health benefits but quality of life…and what else matters, when you get right down to it?

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