SITE REDUNDANCY IN URBAN OZONE MONITORING

This article describes two statistical methods that enable air polluti on control agencies to assess the effectiveness of the spatial distrib ution of current stationary ozone monitoring networks by providing mea sures of site redundancy. These methods analyze site redundancy by det ermining the degree to which ozone measurements at one site can be suc cessfully predicted from data collected at other monitoring sites. The first method, the similarity (SIM) measure, calculates redundancy bas ed on the percentage of common operational days during which two monit oring stations report similar daily maximum ozone concentrations. The second method, a modeling technique, relates site redundancy in ozone measurement to an R-squared statistic from an autoregressive model. Th e model uses meteorological components recorded at a central location and ozone concentrations reported by the network's other monitoring st ations. Both techniques can assist in effective allocation of limited monitoring resources and offer a statistical approach to ambient air m onitoring network design. The techniques are applied to data collected at six ozone monitoring stations in Harris County, Texas, during an e ight-year period in the 1980s. The methods identified two sites in the six-site network that exhibit a high degree of redundancy.