title: Development of an empirical model to estimate real-world fine particulate matter emission factors: the traffic air quality model.
abstract: The purpose of the study was to quantify the impact of traffic conditions, such as free flow and congestion, on local air quality. The Borman Expressway (I-80/94) in Northwest Indiana is considered a test bed for this research because of the high volume of class 9 truck traffic traveling on it, as well as the existing and continuing installation of the Intelligent Transportation System (ITS) to improve traffic management along the highway stretch. An empirical traffic air quality (TAQ) model was developed to estimate the fine particulate matter (PM2.5) emission factors (grams per kilometer) based solely on the measured traffic parameters, namely, average speed, average acceleration, and class 9 truck density. The TAQ model has shown better predictions that matched the measured emission factor values more than the U.S. Environmental Protection Agency (EPA)-PART5 model. During congestion (defined as flow-speeds < 50 km/hr [30 mi/hr]), the TAQ model, on average, overpredicted the measured values only by a factor of 1.2, in comparison to a fourfold underprediction using the EPA-PART5 model. On the other hand, during free flow (defined as flow-speeds > 80 km/hr [50 mi/hr]), the TAQ model was conservative in that it overpredicted the measured values by 1.5-fold.
authors.affiliation: School of Civil Engineering, Purdue University, West Lafayette, IN 47907-1284, USA. soliman@purdue.edu
authors.forename: Ahmed S M
authors.initials: AS
authors.lastname: Soliman
authors.forename: Robert B
authors.initials: RB
authors.lastname: Jacko
authors.forename: George M
authors.initials: GM
authors.lastname: Palmer
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D004781:Environmental Exposure; D004784:Environmental Monitoring; D007196:Indiana; D008962:Models, Theoretical; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis*; D001335:Vehicle Emissions / Q000032:analysis*; D014919:Wind
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D001335:Vehicle Emissions