what is the problem?
The air in Mexico city (19.0000° N, 99.1333° W) contains an unbelievable concentration of particulates such as PM-10 (particulate matter 10um) and also a lot of heavy metal particles, some of which are radioactive and are capable of causing radiation poisoning. Mexico City has some of the most hazardous airquality, comparative to its size, in the world. While the ever-increasing levels of pollutants such as carbon dioxide and monoxide continue to grow, these particles float around in the air for the residents of Mexico city to breathe in. As a result, Mexico City has very high rates of diseases such as asthma, chronic lung and chronic heart disease...
Background To Mexico's Air Quality
Mexico city for an extensive period of time has been a city plagued by the imminent dangers of poor air quality, as a result of geographical features and human interference within the city. Mexico City is one of the largest mega cities within the world and lies within the crater of an extinct volcano 2240 meters above sea level commonly referred to as the Mexico basin or valley. Because of the height and location, the surrounding land-forms create a natural windbreak stopping the disperse of air pollutants that blanket the city.
Figure 1.1: latitude and longitude map of Mexico and displays its main geographical position as a mega city and all its main cities. Mexico city located at 19 degrees 26 minutes North and 99 degrees 7 minutes West.
Source: http://www.mapsofworld.com/lat_long/mexico-lat-long.html#
Source: http://www.mapsofworld.com/lat_long/mexico-lat-long.html#
Figure 1.2: (Geographical Information System) of the Mexico City Metropolitan Area. From this map you are able to see that the city is surrounded by mountains that provide the city with a natural windbreak preventing the dispersion of air pollutants. You can see how its geographical placement can affect both the air circulation and the frequent thermal inversions trap the pollutants at ground level because of the suppression of convection currents, leading to a never-ending cycle of smog.
Source: Mario & Luisa Molina Lecture "The Mexico Air Quality Case Study" Slide 2
Source: Mario & Luisa Molina Lecture "The Mexico Air Quality Case Study" Slide 2
Figure 1.3: A rough cross-section between the ends of the valley of Mexico. It shows the general geological features of the earth underneath Mexico City. There are two mountains (mountainous regions) on either side of the mega city which from a natural crater around Mexico City or a basin in which Mexico city is situated. Because of this the wind patterns and convection currents are altered according to the environment which leads to pollutants never being circumvented.
Source: http://www.idrc.ca/EN/Resources/Publications/openebooks/666-7/index.html
As well as the surrounding crater providing a natural windbreak, the city is also approximately 2240 meters above sea level. At 2240 meters the oxygen levels are 23-30% lower and causes incomplete combustion of fuel within motor vehicles thus increasing the emissions of pollutants into the air as shown in Figures 1.1, 1.2 and 1.3. These images display the position and altitude contributing to these factors.
Mexico City's air quality reached a crisis point in the early 1990's. According to the World Health Organisation (WHO), 8 hours of exposure to ozone gas exceeding 100 micro-grams per cubic meter, will do significant damage to human health. Within Mexico City, the ozone gas exceeded the WHO standards on 92% of the days. Such poor air quality caused chronic respiratory illnesses and aggravated cardiovascular diseases, forcing many people to avoid outside activity in times of intense air pollution.
The Mexican government during the early 1990's saw this as an extremely serious situation, and came up with several major programs that improve the air quality. From 1990 to 2005, the pollution levels within the air has dropped partially however in 2005 Mexico City's air quality still exceeded the WHO standards 79% of all days.
Mexico City's air quality reached a crisis point in the early 1990's. According to the World Health Organisation (WHO), 8 hours of exposure to ozone gas exceeding 100 micro-grams per cubic meter, will do significant damage to human health. Within Mexico City, the ozone gas exceeded the WHO standards on 92% of the days. Such poor air quality caused chronic respiratory illnesses and aggravated cardiovascular diseases, forcing many people to avoid outside activity in times of intense air pollution.
The Mexican government during the early 1990's saw this as an extremely serious situation, and came up with several major programs that improve the air quality. From 1990 to 2005, the pollution levels within the air has dropped partially however in 2005 Mexico City's air quality still exceeded the WHO standards 79% of all days.