Air Pollution in Mexico City
Mexico City adds an estimated one million new residents each year, resulting in one million new aggravates to the city’s already abominable air quality (Collins, 119). Over the span of a generation, Mexico City’s air has gone from being one of the world’s cleanest to one of the world’s most polluted, as well as the most polluted in its country. The average visibility in the city is down from almost 100 km in the 1940s to only 1.5 km today, removing the once beautiful landscape of the surrounding snow-capped volcanoes (Yip, 1). More significantly, however, Mexico City’s air problems have resulted in a notable decrease in the health of its residents, particularly its children. There are a variety of reasons for the decline in air quality, including factory emissions, suspended particles, vehicles, as well as problematic geographic hindrances. Fortunately, Mexico City is doing a lot in response to the problem, including vehicle control, mass transit improvements, required industry emission reductions, and an investing in research and education programs. Regardless of these actions, however, Mexico City’s air is still significantly affecting the quality of life for its residents, and the city must continue to make changes in order for real progress to occur.
Vehicles are responsible for up to eighty percent of air pollution in Mexico. There are close to four million automobiles, buses, and trucks in the city, the average of which is ten years old, and thus in poor repair with ineffective emission controls. Emissions are increased by the excessive traffic compressed into narrow streets with few parking spaces, requiring low-speed cruising (Collins, 125). Even new engines often perform at only sixty percent of combustion efficiency because of the city’s elevation: “there seems to be an essentially linear relationship between increases in elevation and emissions of hydrocarbons in carbureted engines… with the reduced air pressure and the large diurnal temperature range at the elevation of the city, significant quantities of hydrocarbons are released even when engines are not running” (Collins, 125).
Other leading causes of air pollution in Mexico City are the nearly 500 factories, refineries, and power plants in the city classified as high polluters. Few factories have properly installed or maintained emission controls, while many have none at all. Furthermore, because the price of noncompliance fines is lower than new equipment, there is little incentive for owners to change. Industrial enterprises produce ozone precursors that react in the presence of sunlight to form ground level ozone, which leads to ozone-rich photochemical smog (Collins, 126). Though it is improving, in the late 1990s Ozone levels exceeded acceptable standards 300 days a year (Yip, 3). Suspended particles—all particles in the atmosphere smaller than 20 microns—are also responsible for much of Mexico...