A methodology is presented for designing a carbon monoxide monitoring network based on the objective of identifying concentrations that exceed the national ambient air quality standards (NAAQS). The basis for identifying concentrations in excess of the NAAQS is the Concentration Area Time-Product, where the concentrations are integrated over an area (i.e., a grid square in a gridded system) and integrated over a time interval for averaging the concentrations. These are computed with a mesoscale air quality simulation model formulated as a 4-dimensional (x,y,z,t), partial differential equation of mass balance for the pollutant species which yields space-time average concentration distributions. A frequency-weighted average of concentrations called Figure of Merit is determined from these projected concentration distributions, prevailing meteorological patterns, and the frequency of occurrence associated with each of the meteorological patterns. A mapping of these Figure of Merit values provides the basis of selection of the locations and number of sites in the network. The methodology was applied in a design of an ambient air monitoring network for carbon monoxide. The establishment of a field measurement program is described which would provide air quality and meteorological data for model validation and simulation as required in development of the specifications for the number and location of sites in the network design. Discussions are limited to the design methodology. Actual field data, simulation exercises, pollution concentration isopleths, and mappings are presented in a separate report.

Prepared by Systems Applications, Incorporated in cooperation with Environmental Monitoring and Support Laboratory under contract no. 63-03-2399. Issued March 1977. Includes bibliographical references (pages 49-52).