عنوان

Characterization of Dispersion and Ultrafine Particle Emission Factors Using near Roadway Field Measurements

شماره

TL51225

زبان متن نوشتاري يا گفتاري و مانند آن

انگلیسی

عنوان اصلي

Characterization of Dispersion and Ultrafine Particle Emission Factors Using near Roadway Field Measurements

نام عام مواد

[Thesis]

نام نخستين پديدآور

Xiang, Sheng

نام ساير پديدآوران

Noll, Kenneth E.

نام ناشر، پخش کننده و غيره

Illinois Institute of Technology

تاریخ نشرو بخش و غیره

2019

متن يادداشت

150 p.

جزئيات پايان نامه و نوع درجه آن

Ph.D.

کسي که مدرک را اعطا کرده

Illinois Institute of Technology

امتياز متن

2019

متن يادداشت

Recent epidemiology evidence suggests that vehicle emissions are major contributors to poor urban air quality. Human exposure to elevated concentration of traffic emissions has been associated with increased risk factors for a range of negative health outcomes. Evaluation of human exposure to vehicle emissions (e.g. ultrafine particles) mainly relies on dispersion models. Consequently, dispersion models need to comply with constantly increasing requirements to provide predictions of pollutant concentration. The dynamic of near roadway dispersion process needs to be investigated since most of the existing models does not account traffic condition variability (e.g. vehicle type and mode of operation) for dispersion. A five-year long field study was conducted to characterize dispersion near roadway with various vehicle mode of operation and vehicle type. To better understand the dispersion process near roadway, the impact of different ambient background categories (e.g. remote, lake, urban, industrial) on ultrafine particles (UFPs) need to be evaluated. Results demonstrate that each category has a different average ambient background concentration (pt cm-3) as follows: remote, 2,700; lake, 6,000; industrial 12,000 and urban 11,000. The large variations exist in ambient background concentration will result in significant variations in near roadway concentrations. The total near roadway measurements are generally near 20,000 pt cm-3 and reach to 60,000 pt cm-3 depending on the background and traffic emission. The dispersion near the roadway is also investigated in this study. A roadway restricted to light-duty vehicles (LDVs) was selected to conducted near roadway field measurement. Results indicate that the dispersion induced by vehicles is a two-stage process. When under the unsteady-state condition with small number of operating vehicles, the rate of dispersion near roadway increased from 2 m2 s-1 to 6 m2 s-1 as the number of vehicles increased. For steady-state condition, the rate of dispersion was constant near 6 m2 s-1 and not increased with additional vehicles. For a roadway mixed with both LDVs and heavy duty vehicles (HDVs), similar results were found. Dispersion increased from 6 to 18 m2 s-1 as total vehicle flow rate increased to 10,000 veh h-1 and HDV flow rate increased to 1000 veh h-1. Finally, the calculated dispersion near roadway is used to estimate the UFP emission factors. The UFP emission factors were ranged from 0.5 × 1013 to 1.5 × 1013 pt km-1 veh-1 and from 7 × 1014 to 20 × 1014 pt km-1 veh-1 for LDVs and HDVs, respectively. The variations in UFP emission factors are due to change in vehicle mode of operation. The results from this study will be critical for parameterization of dispersion near roadway and provide important emission inventory for interdisciplinary partnership among different fields (e.g. air quality, transportation design and urban planning) in solving transportation air quality problem.

اصطلاح موضوعی

Environmental engineering

مستند نام اشخاص تاييد نشده

Xiang, Sheng

مستند نام اشخاص تاييد نشده

Noll, Kenneth E.

مستند نام تنالگان تاييد نشده

Illinois Institute of Technology

نام الکترونيکي

فرمت انتشار

p

نوع ماده

[Thesis]

کد کاربرگه

276903

سطح دسترسي

a

تكميل شده

Y