Tuesday, May 23
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TOPAZ data were taken from 08:04 - 22:04 PDT. Hot temperatures with a high around 40 C, light winds. Locally produced ozone built up in the afternoon reaching a maximum concentration of about 80 ppbv at the surface and throughout the 2-km deep BL. The Clark County DAQ site Walter Johnson recorded a MDA8 ozone value of 71 ppbv, which exceeded the NAAQS. A high-ozone layer (80 - 90 ppbv) was observed above 6 km AGL.