ANALYTICAL AND EXPERIMENTAL ASSESSMENT OF HIGHWAY IMPACT ON AIR QUALITY

Air quality measurements along Houston freeways have been made at an "at-grade" site and are to be started shortly at a "cut" site. These measurements are used to characterize carbon monozide concentrations downwind from highway line sources. Measurements at each site consist of carbon monoxide concentrations at 10 locations, vehicle length, speed and count by lane, and detailed meteorological data from four states between five and 101.5 feet. All of the instruments are interfaced to a Data General Nova 1200 computer which allows the data to be taken simultaneously and on a rapid time basis. The data from the experimental program will be used to verify line source dispersion models for Texas. Experimental data from essentially all previous experimental programs have been assembled and used in developing and verifying an improved roadway dispersion model. The improved model along with the well known models of CALINE-2, AIRPOL-4 and HIWAY were compared to the data from the previous programs. Significantly improved results were obtained with the modified model. All of the models and all of the previous data are based on one hour average concepts. The data from the current experimental program have not been compared to the models at this time. /Author/