Mexicali Valley Centre

Phase OnePhase TwoPhase Three
Centre:Mexicali Valley, Mexico ( Latin America )
Principal Investigator:Dr J Valente Merida-Palacio
Age Groups:13-14, 6-7Timeframe:May 2002 to November 2002
Sampling Frame:All schools in Mexicali


Dr Juan Valente Merida-Palacio

Dr Juan Valente Merida-Palacio

Pediatric Allergist
Director of the Investigation Center for Allergic and Respiratory Diseases
Member of the board of the Ecology and Environment Control Department,
Air Quality section, for the city of Mexicali, Baja California,


  • Phase Three Principal Investigator for Mexicali Valley

Mexicali is a 1 million population city, located in the northwest of Mexico, border with Imperial Valley of California. It is a desert region, near to the Colorado River, surrounded by more than 2 million acres of agricultural land in both sides of the border.

Our city has a severe air pollution problem, mainly by PM10 and Carbon Monoxide (CO) pollutants, this is due to the mainly for the ground composition (geological material), ashes ( (anthropological sources, mainly agricultural) and other natural components (silica, aluminum), and the lack of control of the motor engine vehicle emissions. These rates of PM10 on air accounted for more than 150,000 tons/year. For this reason Mexicali is considerate the most polluted city of Mexico regarding those particles.

In consequence the morbidity and mortality rates of respiratory diseases are very high, among high risk population, mainly in the pediatric group.

Mexico has several prevalence studies for asthma and allergic rhinitis, but the methodology used is poorly reliable, it was limited to fewer cities, and they were not specific for the pediatric age group. We have not had any prevalence studies for eczema.

On the late 1990’s, the ISAAC phase I was done in Cuernavaca city, as an investigation supported by the National Institute of Public Health, and directed by Prof Isabelle Romieu.

In the Mexican Collage of Pediatric Allergy and Immunology, we felt that we needed to open the project to the most cities as possible, to enlarge the information on different regions of our country.

In 2000 we met Dr Javier Mallol, Chairman for Latin America ISAAC project and talked about the possibility to develop in Mexico the ISAAC phase III, he agreed. The total of 9 centers were we divided the country, in Gulf of Mexico are: Cd. Victoria, Monterrey, Villahermosa, and Merida centers, center: Mexico city (3) and Toluca, and Northeast: Mexicali Valley were enrolled and coordinated by the epidemiology section for the MEXICAN COLLAGE OF PEDIATRIC ALLERGY AND IMMUNOLOGY to start the phase III of this project.

The information obtained ISAAC phase III in Mexicali Valley Center, has been incorporated to the official statistical data of our city. Gone to be used to plan strategies intended to control and diminish the severe air pollution of our area, helping to improve the air quality and the quality of life of the general population.

We are hoping to be participating in this great project and contribute to expand the knowledge of the allergic diseases in our pediatric population.