The Crittenden County Ozone Study (CCOS)
Arkansas News Bureau (September 7, 2005) “Hot weather conditions and a plume of smog are hurting efforts to meet stringent ozone conditions in an eastern Arkansas county...”
It’s a classic environmental conundrum. How does mostly rural Crittenden County, Arkansas, accommodate economic development in an ozone non-attainment area when most of the major (NOx & VOC) precursor emissions sources reside in other counties? A sound, science-based understanding about ozone in and around Memphis was needed to help determine credible attainment strategies.
Towards this end, under the overall direction of Arkansas and in collaboration with federal, state and local regulators and the Tennessee Valley Authority, the Crittenden County Ozone Study (CCOS) was conducted during the 2005 ozone season. This effort collected detailed air quality and meteorological measurements in the Memphis area. CCOS deployed four additional surface air quality and meteorological stations and an instrumented aircraft. The initial results of the rich CCOS data set present a very interesting picture. Among the most important results:
• Aircraft measurements tracked the Memphis ozone plume more than 60 km.
• Surface monitoring revealed that Memphis, on average, contributes 25 ppb above background.
• On days (32) with hourly ozone values >90 ppb, Memphis contributes 40 ppb above background.
• On days (15) with hourly ozone values >100 ppb, Memphis contributes 48 ppb above background.
• Crittenden County is “near enough” to observe high 1-hour ozone and “rural enough” to measure high 8-hour ozone.