The 1996 Paso del Norte Ozone Study: analysis of meteorological and air quality data that influence local ozone concentrations

The 1996 Paso del Norte Ozone Study and subsequent data analyses were imple mented to develop an understanding of the chemical and physical processes w hich lead to high concentrations of ozone in the Paso del Norte study area which includes El Paso County, Texas, Sunland Park, New Mexico, and Ciudad Juarez, Mexico. Both the data and data analysis results are being used to s upport photochemical grid modeling. El Paso County and Sunland Park fail to meet the National Ambient Air Quality Standard (NAAQS) for ozone, and neig hboring Ciudad Juarez fails to meet the Mexican ambient standard for ozone. This paper summarizes the measurement campaigns of the 1996 Paso del Norte Ozone Study and the findings and conclusions that arose from subsequent da ta analyses. Data analyses showed that high ozone concentrations resulted f rom a combination of conditions, including high surface temperatures, stron g sunlight with few clouds. light surface winds and high concentrations of ozone precursors at ground level in the morning, and slow convective bounda ry layer (CBL) growth. Synoptic-scale meteorological conditions observed du ring high ozone episodes included an aloft high-pressure system and aloft w arming. Aloft carryover of ozone and ozone precursors did not significantly contribute to high concentrations of ozone at the surface. (C) 2001 Elsevi er Science B.V. All rights reserved.