The Metropolitan Area of Mexico City (MAMC) is a mega city which houses a population of more than 20 million inhabitants and is considered one of the 10 most populated cities in the world. The increase in the growth rate of the population and the growth of the urban zone have promoted the use of motor vehicles and also increased the energy demand; this has had a direct impact in the air quality. On the other hand, one of the most disturbing effects of air pollution is the deterioration of physical and psychological health of people (Gutierrez et al., 1997). Taking into account the role of personal factors regarding air pollution, such as health and behavior, the need for psychology involvement has become evident. From the perspective of environmental psychology, 4 psychological aspects are considered to understand air pollution. The perceptions (Rodrígues, 1991), the attributional model associated to behavior (Kelley, 1980), the subjective norm (Schwartz, 1981) and the behavioral intention as predecessors of sustainable behavior (Corral-Verdugo, 2010). The cultural and social characteristics of the MAMC have worsened the air pollution problem; because of this a study to understand psychological aspects of the inhabitants of MAMC is necessary. Method First, an exploratory study was performed to understand and define concepts that were culturally relevant. Afterwards, a descriptive study with quasi-experimental design was conducted in order to find the relation among the psychological variables and the differences between groups. The participants were selected by a random quota sampling, including men and women who lived in the MAMC. Three age groups were considered: 15-18, 25-45 and 45-65 years old. A poll was elaborated including 4 scales: perception, attributional model, subjective norm and behavioral intention. Several parametric statistical analysis, including t-test for independent samples, one-way ANOVA and Pearson´s correlations, as well as Analysis of Principal Component were applied for the psychometric and data analysis.Results and discussion About the perception, air pollution is an important problem, the control is in the hands of scientist and government, and psychological effects are perceived. The attributional model is different for each conduct: responsible use of energy and car maintenance is attributed to personal factors, the use of car or public transportation is associated to their particular characteristics (safety, speed, cost) and buying a new car depends on opportunity. In the subjective norm, personal norm seems to be higher than social norm. In order to create a communication program that promotes actions that help improve air quality in the MAMC, we need to understand how those psychological aspects participate as predecessors of pro-environmental behavior. This knowledge would allow generating a more efficient and specific information campaign that promotes environmentally friendly behaviors.