MEXICO CITY FIGHTS BAD AIR Heavily polluted air over Mexico City shows what the city looked like before pollution-fighting actions were taken
SO MANY PEOPLE, SO MANY CARS Almost 4 million cars and trucks are on the streets of Mexico City every day. The result of that traffic is ugly brown air that makes breathing difficult. The city has some of the world’s most polluted air. Because the air pollution is so bad, Mexico City was declared the most dangerous city in the world for children. Breathing the air may lead to asthma and other related lung conditions in young children. Mexico City’s population has grown from 3 million in 1950 to more than 19 million today. It is the second largest city in the Western Hemisphere. Only Sao Paulo Brazil is bigger. In 2011, about 18 percent of Mexico’s entire population lived in Mexico City. There are almost as many people in Mexico City as there are in all of Australia. Emissions from millions of vehicles are the primary source of the city’s air pollution. Almost one-­‐third of these vehicles are more than 20 years old. These older vehicles are less efficient and cause more pollution than newer vehicles. DOWN IN THE VALLEY Geography plays a major role in Mexico City’s ongoing story of smog. Smog is a haze or fog combined with air pollutants. Because of the city’s altitude (about 7,300 feet above sea level), its atmosphere has less oxygen. As a result, fuels do not burn completely, causing high levels of soot particles. Sunlight reacts with pollutants in the air making the smog worse. Mexico City is located in a valley surrounded by mountains on three sides. The colder mountain air above the city traps the warmer polluted air below. Mountains block winds that could drive away the smog, which sits over the city for long periods of time. The smog is especially bad during the winter. At Christmas time thousands of shoppers and tourists pour into Mexico City. That adds more pollutants. In addition, the traditions of shooting off fireworks or having huge fireworks displays at the holiday season add more soot and particles to the already thick air. BREATHING: A HEALTH HAZARD The smog contains tiny particulates known as PM10. They are an especially serious threat to human health in Mexico City. PM10 particulates are about one-­‐seventh as thick as a human hair. Because of their tiny size, they can reach the deepest parts of the lungs. Health problems caused by PM10 include more frequent and more severe asthma attacks. PM10 also increases lung diseases such as bronchitis, and it reduces the body’s ability to fight off infections. Another recent study determined that the city’s bad air is causing people to lose their sense of smell. Thousands of vehicles pour into Mexico City’s streets during rush hour, causing the level of air pollution to increase
Children and the elderly are particularly at risk from the effects of PM10. In 2007, researchers concluded that Mexico’s City’s polluted air prevents children’s lungs from growing properly. Such early damage may lead to lung disease later in life. A study released in 2011 showed that air pollutants appear to reduce children’s ability to learn. HIGH COST OF BAD AIR Climb into the car, join a giant snarl of traffic, and inhale exhaust fumes for two or three hours. That is the beginning of the workday for most residents of Mexico City. Time spent commuting while breathing bad air reduces the quality of life. This is one of the several costs associated with polluted air. Air pollution is expensive. One study showed that a 10 percent reduction in PM10 and ozone levels would save Mexico City residents an average of $760 million a year in health care costs. In addition there would be at least 33,000 fewer emergency room visits. Hospital admissions would drop more than 4,000. People would live longer and each year 266 fewer infants would die. A VARIETY OF SOLUTIONS Over the last 20 years, Mexico City’s government has worked to improve the city’s bad air. The city’s 15 year Plan Verde, or Green Plan, aims to reduce 7 million metric tons of auto emissions-­‐ discharges as a result of burning fossil fuel. To measure pollution, the city has installed air-­‐quality monitoring stations. Plans also include the addition of a 12th subway line and a more energy-­‐ efficient taxi fleet and bus system. To reduce vehicle traffic, the city has told drivers that they must leave their cars at home one day a week. License plate numbers are used to decide which day of the week a person may not use his or her car to commute. Car owners must have their vehicle exhaust systems certified safe every six months. The city also encourages bicycle riding, which also reduces pollution levels. In 2010 the city launched Ecobici, a shared bike program. Ecobici means “ecological bicycle.” Eleven hundred bicycles were installed at 85 stations. Users pay an annual fee of $24 to use the bikes for 30 minutes at a time. Twenty-­‐four thousand users logged a total of 1.2 million trips the first year, for an average of 9,000 trips per day. Plans call for expanding the number of stations to 275 and the number of users to about 73,000. Bicycles help reduce air pollution in Mexico City
Over the past 20 years, Mexico City has succeeded in significantly reducing levels of lead, carbon monoxide and sulfur in the air. However, because of the city’s size and its unique geographic situation, smog remains a serious According to the director of Mexico City’s air quality monitoring service, the only way that the smog will completely disappear is if people stop driving automobiles.