Tipos de polución

Types of Pollution
Air pollution is a current environmental issue.
There are several types of pollution, and while they may come from different sources and have different consequences, understanding the basics about pollution can help environmentally conscious individuals minimize their contribution to these dangers. The sources of pollution don't simply have a negative impact on the naturalworld, but they can have a measurable effect on the health of human beings as well.
Air Pollution
Air pollution is defined as any contamination of the atmosphere that disturbs the natural composition and chemistry of the air. This can be in the form of particulate matter such as dust or excessive gases like carbon dioxide or other vapors that cannot be effectively removed through natural cycles,such as the carbon cycle or the nitrogen cycle.

Air pollution comes from a wide variety of sources. Some of the most excessive sources include:
*Vehicle or manufacturing exhaust
*Forest fires, volcanic eruptions, dry soil erosion, and other natural sources
*Building construction or demolition

Depending on the concentration of air pollutants, several effects can be noticed. Smog increases,higher rain acidity, crop depletion from inadequate oxygen, and higher rates of asthma. Many scientists believe that global warming is also related to increased air pollution.

Air pollution in the large cities of Mexico is becoming a serious concern for both local and national governments. Mexico City, Guadalajara and Ciudad Juarez are the most polluted, with Mexico City's air quality beingamong the worst in the world. According to the World Health Organization (WHO), Mexico City's air averages 179 mg per cubic meter of suspended particulates, well above the WHO 90 mg maximum recommendation.

Exhaust fumes from Mexico City's 3 million cars (approximately) are the main source of air pollutants. Problems resulting from the high levels of exhaust are exacerbated by the fact that MexicoCity is situated in a basin. The geography prevents winds from blowing away the pollution, trapping it above the city. Guadalajara, Mexico's second largest urban center, exceeds pollution limits 90% of the year, due largely to the large number of vehicles operating in the city. Ciudad Juarez, a border city of 1.4 million inhabitants, is home to many assembly plants ("maquiladoras") that areresponsible for the release of dangerous substances into the environment.

Though automobiles still account for 90% of air pollution, industrial growth is also causing increased environmental damage to the area. Air pollution in northern Mexico also impacts U.S. border areas. The Mexican government has presented several innovative proposals for fighting air pollution, including incentives for usingcleaner fuels and smog control measures. In major urban centers, private car drivers are required to have catalytic converters or refrain from driving one day a week. The pollution fighting measures put in place in the mid-1990s have already improved visibility and air quality in the city. Mexican environmental initiatives include developing clean taxis and small buses in order to reduce urbanemissions; improving environmental infrastructure; and strengthening the northern border regions' environmental planning and administration.

Mexico City is one of the largest cities in the world with a population close to twenty million people. The majority of the population is exposed daily to fumes produced by 3.6 million vehicles. This, of course, means that many roads throughout Mexico City arehighly congested.

In addition to this, many vehicle owners fill up their vehicles with poor quality fuel.
These vehicle fumes coupled with other air pollution sources are responsible for many residents suffering from severe respiratory health problems.

It has been known for many years that the air pollution in Mexico City is much worse than that found in similar sized cities in other...