Plan to reduce air pollution chokes in Mexico City

Plan to reduce air pollution chokes in Mexico City
The Mexico City Metropolitan Cathedral was built by the Spaniards over the ruins of the main Aztec temple. Credit: Jeff Kramer/Wikipedia

Decades ago Mexico City's air pollution was so poor, birds would fall out of the sky—dead. Locals said living there was like smoking two packs of cigarettes a day, according to one report. In response, Mexico City took several steps to try to improve air quality including restricting driving one or two days during the weekdays. The program has had negligible results.

In 2008, the city added on Saturdays in hopes of moving the needle but according to new research by Lucas W. Davis, an associate professor at UC Berkeley's Haas School of Business, extending the program one more day also isn't working.

"Saturday driving restrictions are a flawed policy. It's a big hassle for people and does not improve air quality," says Davis, who is also the faculty director at the Energy Institute at Haas.

The study, "Saturday Driving Restrictions Fail to Improve Air Quality in Mexico City," published today in Scientific Reports, is the first to examine the effects of restricted driving on Saturdays. It compares of eight major pollutants before and after the program went into effect. Having fewer motorists on the road on Saturdays led to close to zero impact. Proponents of the Saturday program had estimated vehicle emissions would be reduced by 15% or more.

Mexico City has the worst air quality in the Western Hemisphere with particulate levels that are three to four times higher than in New York, Los Angeles, São Paulo, or Buenos Aires, the paper states. Mexico City has tried many different approaches to improving air quality, including the city's well known driving restrictions, which were first introduced in 1989.

The program works like this: restrictions are based on the last number of a vehicle's license plate. For example, vehicles with license plates ending in "5" or "6" cannot be used on Mondays. The ban is in effect from 5:00 a.m. to 10:00 p.m. for both personal and commercial vehicles.

To determine the impact of Saturday restrictions, Davis analyzed hourly data from 29 monitoring stations around Mexico City from 2005 to 2012. He studied emission levels for carbon monoxide; nitric oxide; nitrogen dioxide; nitrogen oxide; ozone; large particulates; small particulates; and sulfur dioxide. None of these pollutants decreased as a result of Saturday driving restrictions.

Trying to figure out why pollution did not decrease, Davis next examined ridership data from Mexico City's public transportation systems. From buses, to light rail, to electric buses, he found no discernible increase in Saturday riders.

"People have found other ways to get around the driving restrictions," says Davis. "Some purchase multiple cars, others take taxis or Uber."

Davis argues that as Uber and other taxi-like services become increasingly available, driving restriction policies will continue to struggle to improve . Instead, he suggests that Mexico City and other cities plagued by dangerous pollution need to require stricter vehicle emission tests.

"Test every car, test every year. If you have a car that's polluting the air, you can't drive it. Period," says Davis.


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More information: Lucas W. Davis. Saturday Driving Restrictions Fail to Improve Air Quality in Mexico City, Scientific Reports (2017). DOI: 10.1038/srep41652
Journal information: Scientific Reports

Citation: Plan to reduce air pollution chokes in Mexico City (2017, February 2) retrieved 24 May 2019 from https://phys.org/news/2017-02-air-pollution-mexico-city.html
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Feb 02, 2017
Just keep on making the oil barons rich as we kill ourselves with their pollution.

Our car is an EV, powered by the PV panels on our roof.

It is now practical to do so, and folk are smart to look into it right now.

Feb 02, 2017
"Our car is an EV, powered by the PV panels on our roof."

People are so hideously selfish. Yay for you.

I guess the little rich guy has given himself a reason to make himself feel superior. You probably have a larger income than ten Mexican citizens put together, therefore are able to afford your little toys.
I can't even afford a new EV car with all of the associated equipment required to charge it, and I make decent money.


Feb 02, 2017
I can't even afford a new EV car with all of the associated equipment required to charge it, and I make decent money.

...and the poorest are stuck buying the replacement parts...

Feb 02, 2017
I guess the little rich guy has given himself a reason to make himself feel superior. You probably have a larger income than ten Mexican citizens put together, therefore are able to afford your little toys.
I can't even afford a new EV car with all of the associated equipment required to charge it, and I make decent money
Ahahhahhhh he cant afford it either. From what he has inadvertantly revealed, george kamburoff hasnt worked in a decade or 2. He is a psychopath who made up the story about his PV and EV just so he could get a rise from noobs like yourself.

So do you feel better or worse now?

Feb 03, 2017
Just keep on making the oil barons rich as we kill ourselves with their pollution.Our car is an EV, powered by the PV panels on our roof.It is now practical to do so, and folk are smart to look into it right now.


To prove you really care about Mexico's environment you need to PROVE you really care about it, you need to share your EV & your house with some Mexicans.

Sharing with others is how to PROVE you really care, otherwise you are just squandering the world's LIMITED resources on your own SELFISH lifestyle. A lot of CO2 went into the atmosphere to build that EV you drive around in, and it was probably built in Mexico making you personally guilty than many of the rest of us for Mexico's environmental plight, you selfish inconsiderate slob.

I think I've read somewhere that there's a GOLDEN RULE about sharing, maybe Ghosty can find it for us & put it up.

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