Green Infrastructure in Mexico City - Recommendations to improve air quality and climate conditions

Abstract

Environmental alert in Mexico City: In May 2019, the air pollution situation worsened to such an extent that the environmental alert was declared for several days. The people in the metropolis of almost 22 million inhabitants were exposed to extreme concentrations of various air pollutants. But even when the environmental alert has not been declared, there is an increased health risk in the Mega City for almost the entire year. Parallel to this, environmental precaution in urban development is gaining international importance. The "Health in all Policies" strategy of the World Health Organization makes it clear that spatial planning has a responsibility for the health of the population. This can be used to justify an obligation to develop strategies that counteract the causative factors of deficient conditions in terms of climate and air quality. In the case of Mexico City, the causative factors can be identified in particular as anthropogenic processes, such as road traffic, but also topographical conditions, enormous uncontrolled urbanization that took place in the past, certain weather conditions and, last but not least, climate change. Green infrastructure offers a major contribution to environmental care in cities. Green infrastructure can filter air pollutants, brings cooling, and can also be a ventilation pathway for cold and fresh air flows. Beyond this, however, there are many more environmental synergies. The recreational function that Green Infrastructure provides should also not be underestimated. The research work took place within the author's master's thesis. It is about the potentials that Green Infrastructure has to improve the conditions of climate and air quality in Mexico City. It examines the possibilities of improving the general situation, the possibilities of preventing extreme climatic events, and the possibilities of contributing to a livable and healthy city. For this purpose, it analyzes where exactly the problems lie, which planning concepts in relation to Green infrastructure can counteract these problems and, furthermore, which lessons can be learned from previous policies and measures in this regard in order to be able to ensure the feasibility of recommended measures. The result of this work is concrete proposals for a green and open space strategy that has its scope of application not only in Mexico City itself, but beyond that in the entire metropolitan region. The green and open space strategy proposes four fields of action to expand the stock of green infrastructure: the systematization of roadside greenery, the development of new green areas, the greening of roofs and facades, and the maintenance and upgrading of climatically effective and valuable areas. These fields of action are to be implemented in particular in the form of individual projects. Two concrete project examples illustrate possible organizational structures and potential spatial alternatives within the existing settlement structure. This article presents the main analysis results and formulated recommendations and concepts from the research.