Monterrey, Mexico, ozone study: air quality measurements

The Monterrey Metropolitan Area (MMA) of Mexico has often experienced episodes with ozone concentration higher than Mexican ambient air quality standard (110 ppb). MMA is one of the most rapidly growing industrial and urban areas in the north of Mexico. This paper describes aspects related to field measurements that will be used to evaluate a photochemical urban model with the environmental and geographical characteristics of Monterrey. The model employing the Carbon Bond Mechanism IV is being developed with a hybrid method for solving the stiff ordinary differential equations. Data analysis of the field measurements is used to characterize prevailing conditions in the behavior of the air quality levels. Also, diagnostic activities provide better bases to estimate reasonable and consistent global inventories. The results provide information for testing air quality models and to establish a foundation for future studies and control strategies. Measurements over the study region consist of: (a) surface air quality data (ozone, nitrogen oxides, carbon monoxide, temperature, wind speed, and wind direction) obtained by five existing monitoring stations operating from 1992, (b) meteorological data (temperature, pressure, and relative humidity) measured by state stations, (c) emissions data measured (carbon monoxide and hydrocarbons) in vehicle exhaust pipes from September 1991 to April 1992.