An Empirical Relationship Between Mesoscale Carbon Monoxide Concentrations and Vehicular Emission Rates: Final Report

About the report:

Presented is a relatively simple empirical equation that reasonably approximates the relationship between mesoscale carbon monoxide (CO) concentrations, areal vehicular CO emission rates, and the meteorological factors of wind speed and mixing height. The approximation is an extension of rollback modeling and was derived from aerometric data measured at a major urban area in Virginia. A similar equation has been found valid for data measured at another major urban area. Transportation planners can use such an approximation in conjunction with a grid inventory of areal vehicular CO emissions to obtain an areal profile of mesoscale CO concentrations. Such an approximation would be preferable to the complex and potentially more accurate diffusion models when reliable input data are not available, which is often the case. It can be used by air quality planners involved in the project-level analyses to estimate the existing worst-case background levels of CO at a proposed urban highway site. This estimation can then be combined with the predicted worst-case CO contribution from the proposed highway project to determine if expensive air monitoring is necessary.

Authors