21 Atmospheric Pollution: Experience from Mexico City …
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space. However, this situation has changed recently due to the expansion of the urban
areas beyond the MCMA forming the Megalopolis (see Fig. 21.1). The Megalopolis
concentrates about 25% of the Mexican population, and a substantial fraction of the
national gross domestic product is derived from the intensive commercial and industrial activities taking place in this region. However, the combination of poorly planned
urban development, inefficient transport systems for a large number of people and
goods, and the continuously growing unsustainable economic activities have exerted
substantial land-use changes in the region, ultimately impacting the air quality and
the environment. The different administrative and regulatory frameworks among the
states of the Megalopolis further contribute to the lack of an integrated sustainable
development programs. In 2013, the Megalopolis Environment Commission (CAMe)
was created to coordinate regional policies and programs.
In recent years there have been several episodes of high O 3 concentrations in
Mexico City and other entities of the Megalopolis. During a notable episode in March
2016, warm temperatures and still air left pollutants trapped in the basin led to high O 3
concentrations, forcing the authorities to declare a Phase 1 contingency, the first since
2005. CAMe developed an Air Quality Management Program (PROAIRE 2017–
2030) for the Megalopolis to address the situation [12]. Subsequently a modeling
study was performed by the Molina Center and collaborators to evaluate the impacts
of the implementation of an integrated comprehensive emission control strategies
identified in the PROAIRE 2017–2030 on ozone concentrations [6].
In this study three meteorological episodes were selected during the period of
high O 3 season (dry-hot season) in the Megalopolis, reflecting the main pollutant
transport conditions in the region and used as the baseline for the modeling and analysis of regional O 3 formation. Baseline emissions for the region from the Mexican
National Emissions Inventory for the year 2013–2014 were provided by the Mexican authority. An integrated emission reduction scenario was designed that includes
all the control strategies listed in the PROAIRE, targeting vehicle, residential, commercial, consumer products, solvents, automobile coatings, painting, wood-burning
and regulations (reduction of 32% NO x and 46% VOCs). The model-ready emission
files were used to simulate O 3 concentrations in the Megalopolis for both the baseline
and the integrated emissions reduction scenario for the three selected meteorological
episodes using a version of the WRF-Chem air quality model [4, 14] developed by
Li et al. [5].
Preliminary modeling results indicate substantial benefits (ozone reduction) in
the northern and northeastern regions of Mexico City and in the cities of Toluca,
Cuernavaca, Pachuca and Querétaro, but negative impacts in the central and southern
regions of Mexico City and also in the Puebla and Tula regions (see Fig. 21.3). These
results were consistent for the three meteorological episodes selected. However, it is
important to note that the evaluation of the impacts on air pollutant concentrations
strongly depends on the accuracy of the emission estimates used in air quality models.
While the MCMA has been the subject of several intensive field studies and has an
extensive ambient air quality monitoring network, air pollution studies are scarce in
the other five states and the air quality monitor stations are not sufficient for analyzing
trends. Therefore, it is important to perform field measurement-based studies of ozone
133
space. However, this situation has changed recently due to the expansion of the urban
areas beyond the MCMA forming the Megalopolis (see Fig. 21.1). The Megalopolis
concentrates about 25% of the Mexican population, and a substantial fraction of the
national gross domestic product is derived from the intensive commercial and industrial activities taking place in this region. However, the combination of poorly planned
urban development, inefficient transport systems for a large number of people and
goods, and the continuously growing unsustainable economic activities have exerted
substantial land-use changes in the region, ultimately impacting the air quality and
the environment. The different administrative and regulatory frameworks among the
states of the Megalopolis further contribute to the lack of an integrated sustainable
development programs. In 2013, the Megalopolis Environment Commission (CAMe)
was created to coordinate regional policies and programs.
In recent years there have been several episodes of high O 3 concentrations in
Mexico City and other entities of the Megalopolis. During a notable episode in March
2016, warm temperatures and still air left pollutants trapped in the basin led to high O 3
concentrations, forcing the authorities to declare a Phase 1 contingency, the first since
2005. CAMe developed an Air Quality Management Program (PROAIRE 2017–
2030) for the Megalopolis to address the situation [12]. Subsequently a modeling
study was performed by the Molina Center and collaborators to evaluate the impacts
of the implementation of an integrated comprehensive emission control strategies
identified in the PROAIRE 2017–2030 on ozone concentrations [6].
In this study three meteorological episodes were selected during the period of
high O 3 season (dry-hot season) in the Megalopolis, reflecting the main pollutant
transport conditions in the region and used as the baseline for the modeling and analysis of regional O 3 formation. Baseline emissions for the region from the Mexican
National Emissions Inventory for the year 2013–2014 were provided by the Mexican authority. An integrated emission reduction scenario was designed that includes
all the control strategies listed in the PROAIRE, targeting vehicle, residential, commercial, consumer products, solvents, automobile coatings, painting, wood-burning
and regulations (reduction of 32% NO x and 46% VOCs). The model-ready emission
files were used to simulate O 3 concentrations in the Megalopolis for both the baseline
and the integrated emissions reduction scenario for the three selected meteorological
episodes using a version of the WRF-Chem air quality model [4, 14] developed by
Li et al. [5].
Preliminary modeling results indicate substantial benefits (ozone reduction) in
the northern and northeastern regions of Mexico City and in the cities of Toluca,
Cuernavaca, Pachuca and Querétaro, but negative impacts in the central and southern
regions of Mexico City and also in the Puebla and Tula regions (see Fig. 21.3). These
results were consistent for the three meteorological episodes selected. However, it is
important to note that the evaluation of the impacts on air pollutant concentrations
strongly depends on the accuracy of the emission estimates used in air quality models.
While the MCMA has been the subject of several intensive field studies and has an
extensive ambient air quality monitoring network, air pollution studies are scarce in
the other five states and the air quality monitor stations are not sufficient for analyzing
trends. Therefore, it is important to perform field measurement-based studies of ozone