Rhys Thom and I recently visited Mexico City where we met with two researchers at UNAM - Mexico’s National University - who are doing some fascinating research. Robyn Hudson, a charismatic professor, originally from Australia who has been living in Mexico City for quite some time, and her colleague Marco Guarneros, a fellow biomedical researcher, conducted a study comparing the ability of Mexico City’s residents to detect certain smells, with the ability of people living in a Tlaxcala, a neighboring town. Mexico City and Tlaxcala are similar in many respects - they share a similar culture and climate, situated high in the mountains of Mexico. But there is one crucial difference: Mexico City has much higher levels of air pollution.
When compared to their neighbors, people living in Mexico City need higher concentrations of a smell in order to identify it, a clear indication that their sense of smell is deteriorating. Read the rest of this entry »
Crystal Davis looks at urbanization and its impact on environment and development in Part I of a three-part series. Check out other analysis by Crystal at http://earthtrends.wri.org.
Now home to half of the world’s people, cities are increasingly at the forefront of our most pressing environmental challenges. While the current pace of urbanization is not unique in human history, the sheer magnitude of urban growth–driven by massive demographic shifts in the developing world–is unprecedented, with vast implications for human well-being and the environment. However, where cities pose environmental problems, they also offer solutions. As hotspots of consumption, production, and waste generation, cities possess unparalleled potential to increase the energy efficiency and sustainability of society as a whole.
Figure 1. Economic and Social Welfare in Urban vs Rural Areas
Cities generate a disproportionate share of gross domestic product (GDP) and provide, on average, greater social and economic benefits to their inhabitants than do rural areas. As a result, increased urbanization often correlates to higher national incomes (see Figure 1 above).
In ancient Indian and Chinese texts, writers noted that the ultimate form of torture involved subjecting captives to loud and horrible noises. It’s an interesting paradox that we now live in the modern world as free citizens, and all we need to do is stroll down the street to be exposed to noise loud enough to become physically ill, elevating our blood pressure to unhealthy levels, interfering with our sleeping patterns, and causing a whole host of stress related diseases.
On the majority of roads in cities like Bangalore, Mumbai, and Delhi, noise pollution can measure nearly 80-90 decibels during peak hours. That’s roughly the equivalent of standing just 15 feet from a passing freight train! Noise levels above 80 decibels are detrimental to healthy hearing and the Australian EPA suggests that prolonged exposure to noise at or above this level can cause deafness. It’s such a serious problem that researchers in the EU found that the social cost of noise pollution for that region is 0.4% of total GDP. In Indian city’s it must be a lot worse. (For normal tension free conversation one requires a background noise level less than 55 decibels.) Read the rest of this entry »
The New York Times reports today that noise on Cairo’s streets averages 85 decibels, the equivalent of standing just 15 feet from a passing freight train. And that’s just the average. In the loudest parts of the city it can reach 95 decibels, only slightly softer than the noise produced by a jackhammer!
The loud noise on the city’s streets is not just a nuisance:
It can cause elevated blood pressure and other stress-related diseases. It can interfere with sleep, which almost always makes people more irritable. “People need a chance to sleep, to have a chance to think, in quiet,” said Dr. Nagat Amer, a physician and researcher with the national center.
Soy beans on the left, and corn, on the right, are being used for bio-fuel. Photo by cindy47452.
Today, Brenda Gorman reports in the New York Times about a rash of cases involving the bio-fuels industry in which industrial waste is improperly disposed, fouling rivers and streams in states like Alabama and Missouri. The title of her article suggests the internal contradictions of a purportedly green business that harms the environment: “Pollution Is Called a Byproduct of a ‘Clean’ Fuel.” As Ms. Gorman writes,
The discharges [from the bio-fuel plants], which can be hazardous to birds and fish, have many people scratching their heads over the seeming incongruity of pollution from an industry that sells products with the promise of blue skies and clear streams.
For the second year in a row, Mexico City has shown that being green can pay. Last week the city was awarded 200,000 Euros from the Spanish Carbon Fund for reducing carbon emissions as part of MetroBus, a bus rapid transit system that has reduced the number of polluting cars on the road.
Metrobús was Launched on June 19, 2005, and carries an average of 260,000 passengers a day. After more than two years in operation, it has carried more than 200 million passengers.
China’s Green Beat, is a neat bilingual blog I stumbled upon the other day, written by John Romankiewicz, an American Fulbright scholar currently living in Beijing, and Zhao Xiangyu, a Chinese citizen from Heilongjiang, a province in the northern part of the country. Check out the above video for a comical take on serious challenge: motorization in the Chinese capital.
Congestion pricing is good for the environment and public health. Photo by dlisbona.
A team of scientists at the London School of Hygiene and Tropical Medicine and King’s College London conducted a study showing that London’s congestion pricing scheme has reduced air pollution in central London, saving Londoners as a whole 1888 extra years of life. The study focused on two types of pollutants from cars: NO2, a chemical compound known to cause acute and chronic bronchitis, and particulate matter (PM10), tiny particles suspended in the air which can become embedded in the lungs, causing asthma and bronchitis.
The authors of the study, which was published in the journal of Occupational and Environmental Medicine, are hardly sanguine about their results, noting that overall London saw only “modest” reductions in NO2 and PM10 levels. However, they also point out that, “Absolute and relative reductions in NO2 and PM10 were greatest within the congestion charging zone wards,” suggesting that an expansion of the zone would have an even greater environmental and health impact. Read the rest of this entry »
Residents of Mexico City have a much poorer sense of smell than their counterparts in the neighboring state of Tlaxcala due, in large part, to the poorer air quality in the Mexican capital. A study by Robyn Hudson, Aline Arriola, Margarita Martinez, and Hans Distel - researchers at UNAM, Mexico’s national university - suggests that the cause is exposure to abnormally high levels of ozone, a chemical compound known to damage the olfactory mucosa, the part of the nose that allows odors to be detected.
“For a megacommunity like Mexico City with more than 20 million inhabitants, this could constitute an important public health issue,” the researchers wrote. The study notes that chilangos, as residents of Mexico City affectionately refer to themselves, had more difficultly identifying trace smells of coffee and orange juice than people who live in neighboring Tlaxcala. What’s more, they had more trouble differentiating between two traditional Mexican drinks, horchata and atole.
Photo by 
Soy beans on the left, and corn, on the right, are being used for bio-fuel. Photo by 
Photo by 
Photo By EMBARQ-WRI.
Congestion pricing is good for the environment and public health. Photo by 
Smog in the city. Photo by 
Subscribe to Posts
Recent Comments