Air quality in Mexico City

Air quality, concern about deposition of toxic chemicals, 135 Air quality in Mexico City atmospheric pollution, sources, 150r carbon monoxide standards, 156r,157/ fuel consumption in metropolitan area and Mexico, 153r,154 fuel quality, 155... 

As part of this MCMA-2003 campaign, glyoxal was detected for the first time directly in the atmosphere (Volkamer et al. 2005a). As is visible from the concentration time profile shown in Figure 1, the rapid variation of glyoxal was well resolved by these time resolved DOAS measurements, which present useful data to validate the performance of photochemical models that are used as tools for the design of control strategies to improve air quality in Mexico City. 

In Mexico City, several air quality parameters are measured continuously by an Automated Monitoring Network operated by the Under Secretariat of Ecology. Carbon monoxide, particulate matter, sulfur dioxide, nitrogen oxide, and ozone are the contaminants exceeding Air Quality Standards. Emissions produced by 2.7 million vehicles and 35,000 commercial and industrial outfits are not easily dispersed in a Valley located at 2240 m and surrounded by two mountain chains which hinder air circulation. An Integral Program, recently established to alleviate pollution, is briefly described. 

Gaffney, J. S., N. A. Marley, and P. V. Doskey, Peroxyacetyl Nitrate and Hydrocarbon Measurements in Mexico City, Invited Paper, Special Session on Mexico City Air Quality, Spring Meeting of the American Geophysical Union (AGU), Boston, Massachusetts, May 25-28, 1998, Atmos. Environ., in press (1999). 

Mexico City suffers from severe air quality problems with maximum ozone values up to 250 ppb. In order to study the effect of different precursor emissions and possible mitigation measures on the ozone levels in Mexico City the MCCM was applied in the Greater Area of the city (Jazcilevich et al. 2003 Forkel et al. 2004). Figure 7.4a shows that, in agreement with observations, the simulated O3 maxima occur in the southwest of the city (measurement station FED), which is down-wind of the city centre, as an uphill flow is prevailing during the afternoon. The minimum ozone concentrations are found in the centre of the city (station MER), where the NO emitted by traffic titrates the ozone, and in the northern part of the city at places where the NO emissions from industry and power plants locally reduce the ozone concentrations (near station XAL). 

Air Quality Modeling and Data Analysis for Ozone and Particulates in Mexico City. MIT Integrated Program on Urban, Regional and Global Air Pollution Report No. 15 (available from http //eaps.mit.edu/megacities/index.html). 

FIGURE 2 Schematic of aerodyne research mobile laboratory deployed for air quality studies in Mexico City. 

Gaffney, J. S., Marley, N. A., Cunningham, M. M., and Doskey, P. V., Measurements of peroxyacyl nitrates (PANs) in Mexico City implications for mega city air quality impacts on regional scales, Atmos. Environ., 33, 5003-5012, 1999. 

The emphasis on air pollution in different parts of the world has led to marked improvements in air quality. However, there are several metropolitan areas in the world where the air pollution situation is still deteriorating. Examples of such areas are Mexico City, Mexico, New Delhi, India, Cairo, Egypt, and Sao Paulo, Brazil. Most of these badly polluted areas are in developing countries where resources for improving the situation are limited. Thus, these problems are difficult to solve (see Fig. 5.30)." ... 

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