David C. Fung, Qunfang Zhang, William C. Hinds, Yifang Zhu

  • University of California Los Angeles, Department of Environmental Health Sciences, 650 Charles E. Young Drive South, Los Angeles, CA 90095, USA

Received: April 3, 2013
Revised: June 5, 2013
Accepted: June 5, 2013
Download Citation: ||https://doi.org/10.4209/aaqr.2013.04.0110  

  • Download: PDF


Cite this article:
Fung, D.C., Zhang, Q., Hinds, W.C. and Zhu, Y. (2013). Particle Concentration on Freeways: Affecting Factors and a Simple Model Development. Aerosol Air Qual. Res. 13: 1693-1701. https://doi.org/10.4209/aaqr.2013.04.0110


 

ABSTRACT


A few field studies have reported high levels of in-cabin ultrafine particles and discussed certain contributing factors such as vehicle operations and atmospheric meteorological conditions. However, to generalize limited field study results to a wide range of conditions, a deeper understanding of affecting factors and a simple model that can predict on-road particle concentrations are essential. This paper has two objectives, first, to analyze the effects of surrounding vehicle density, relative freeway lane position, and vehicle speed on measured particle concentrations on two California freeways, I-405 (5% diesel) and I-710 (25% diesel). The second objective is to test the use of Emission Factor (EMFAC) 2007 and Caline4 (CL4) models in predicting on-road particle concentrations. Particle number and mass concentrations were collected using a mobile laboratory driving on the I-710 and I-405 freeways. Particle number concentration was found to be affected by the density of surrounding heavy duty diesel trucks which is consistent with previous studies. The highest particle number concentrations were measured in the outer lanes on the freeway and the lowest was in the inner lanes. The highest levels of particles were measured at vehicle speeds of 40–50 mph. Analysis of CL4 model was conducted using factor-of-two test. For the I-710, 85% of values were within the factor-of-two envelope, and for the I-405, 77% were within the envelope. Regression analysis showed that the model is able to account for 43% of the variability on the I-710 and 26% of the variability on the I-405. The use of CL4 in conjunction with EMFAC shows promise as a simple tool to estimate on-road PM2.5 concentration.


Keywords: Ultrafine particles; PM2.5; Vehicle emissions; On-road; Caline4; EMFAC


Don't forget to share this article 

 

Subscribe to our Newsletter 

Aerosol and Air Quality Research has published over 2,000 peer-reviewed articles. Enter your email address to receive latest updates and research articles to your inbox every second week.

Latest coronavirus research from Aerosol and Air Quality Research

2018 Impact Factor: 2.735

5-Year Impact Factor: 2.827


SCImago Journal & Country Rank

Aerosol and Air Quality Research (AAQR) is an independently-run non-profit journal, promotes submissions of high-quality research, and strives to be one of the leading aerosol and air quality open-access journals in the world.