| This work presents a cheaper, easier and more flexible alternative to other types of real-world automotive emissions measurement techniques by the use of open-path spectroscopy. The “Tunnel-less Tunnel Study” is described as a method for the direct measurement of fleet and mode-averaged emission factors for CO, N2O, CH4, NH3 and NO.; Through several measurement campaigns in Colorado, 2363 FTIR spectra were collected and analyzed in the cities of Denver and Colorado Springs, as well as in the Rocky Mountain foothills. This technique is shown to be flexible and robust, yielding results that are in general agreement with the literature. The detection-limits and sensitivities of this new application are also investigated and quantified.; The application of these measurements is the creation of a first-ever calculation of a fuel-based mobile-source emissions inventory for the Colorado Springs Area. The results of this inventory are compared to those generated by the computer model used by the Colorado Department of Public Health and the Environment. The only emissions common between both methods are those for carbon monoxide (CO) and nitric oxide (NO). In actuality, the State calculates total nitrogen oxides (NOx) and reports in units of tons NO2. The fuel-based method measures NO directly, but these figures are reported as tons of NO2 for comparison's sake.; Finally, as justification for this method being potentially easier and cheaper than existing methods, the case is made for minimizing the number of days required for an estimation of the fleet averaged emission factors at a particular site. After decreasing the number of sampling days to sets of four, three and two by randomly selecting from the available days at the given site, it was discovered that the uncertainty in the estimate of the CO emission factor increased from 17% to 22%, and that the standard deviation of the group of emission factors calculated in each case was much less than this uncertainty. |
