2013 Session: 585

• Air Quality Regulation in Metros: Benchmarking Approach
  Abstract: This study examined whether air quality regulations designed for other environments were being applied to metros without consideration of the specific attributes of the metro environment. This is a concern because if regulations are overly restrictive metros may incur unnecessary costs and unreasonable regulation, but if regulations are too lax then the health of workers and passengers is at risk. This study therefore benchmarked the air quality regulations being used by metros. A questionnaire revealed that 16 out of 22 responding metros had air quality regulations, all of which were originally intended for non-metro environments. PM10, carbon monoxide, and carbon dioxide were the most commonly regulated pollutants. Less commonly regulated pollutants included benzene, sulphur dioxide, PM2.5 and ozone. Many metros used World Health Organisation recommendations, but for most pollutants there were outliers at both ends of the scale, indicating that regulation in some metros is too lax whereas in others it is overly strict. A set of metro-specific standards is therefore proposed as an international benchmark for metros to use.
  Authors: Cohen, Judith Michelle; Anderson, Richard; Melo, Patricia C.; Hirsch, Robin Charles d'Aubyn; Graham, Daniel
  Authors: Cohen, Judith Michelle; Anderson, Richard; Melo, Patricia C.; Hirsch, Robin Charles d'Aubyn; Graham, Daniel
  Year: 2013
  Document Type: Paper
  Subject: Environment; Public Transportation
  Session: 585
  Paper Number: 13-2476
  Practice-Ready: Yes
• Statistical Study of Variables Associated with Particulate Matter Exposure Levels at Bus Shelters
  Abstract: This study expands upon previous work that examined differences in exposure to particulate matter in and around bus stop shelters for passengers waiting along a busy urban corridor in Portland, OR. An extensive body of literature has demonstrated the negative health effects of exposure to particulate matter. While concentrations of particulate matter are known to be greater near busy roadways, little research has been conducted on exposure in and around bus stop shelters. Two sizes of particulate matter are examined in this study: PM2.5 and ultrafine particles. Pearson association tests are run between particulate concentrations and three categories of independent variables: location, vehicles, and weather. Significant correlations are primarily observed between particulates and weather (temperature and relative humidity). Using one-minute data intervals, a series of log-linear regression models with and without lagged variables are used to estimate the effects of location, traffic, and weather variables on particulate concentrations. The presence of a transit bus stopped at the shelter significantly increases both sizes of particulate matter concentrations. Wind, temperature, and shelter location also have significant impacts on ultrafine and PM2.5 levels. The estimated models for particulate concentrations inside and outside the bus stop shelters are compared to demonstrate differences in particulate behavior. Suggestions are made for shelter configuration given environmental and traffic considerations.
  Authors: Moore, Adam; Figliozzi, Miguel
  Authors: Moore, Adam; Figliozzi, Miguel
  Year: 2013
  Document Type: Paper
  Subject: Environment; Public Transportation
  Session: 585
  Paper Number: 13-2845
  Practice-Ready: Yes
• Idle Monitoring, Real-Time Intervention, and Emission Reductions from School Buses in Cobb County, Georgia
  Abstract: Georgia Tech researchers developed a patent-pending idle detection and warning notification system that features Global Positioning System (GPS)-based real-time tracking and web-based user interface. 480 buses in the Cobb County School District were equipped with the GPS-based idle detection system, and the research team provided bus dispatchers with a web-based system to track vehicle activity and notify idle events exceeding five minutes. The idle detection and warning notification system is able to differentiate idling with engine on from key-on events with engine off, an important capability that sets this system apart from previous studies that only detected key-on events. Idle reductions were monitored and emissions and fuel savings were evaluated using Environmental Protection Agency (EPA)’s Motor Vehicle Emission Simulator (MOVES) model. The idle reduction resulted from implementing the system was statistically significant, achieving more than six minutes of idle reduction per bus per day. Greater idle reduction can be achieved with more stringent implementation of the system. Total annual emissions reduced from the anti-idle program were 1.67 tons of criteria pollutants (NOx, PM, HC, CO), 55.5 tons of CO2, and conservation of 6,400 gallons of diesel fuel. Approximately 41,100 children riding these buses or attending schools served by these buses were positively impacted by the idle reduction system.
  Authors: Xu, Yanzhi; Elango, Vetri Venthan; Guensler, Randall; Khoeini, Sara
  Authors: Xu, Yanzhi; Elango, Vetri Venthan; Guensler, Randall; Khoeini, Sara
  Year: 2013
  Document Type: Paper
  Subject: Environment; Public Transportation
  Session: 585
  Paper Number: 13-4964
  Practice-Ready: Yes
• Meta-analysis of Transit Bus Exhaust Emissions
  Abstract: Though many specific studies of bus emissions exist, this paper addresses the need for a comparative analysis of emissions associated with a variety of fuel types, specifically for developing countries. This paper compiles a large data set of in-use transit bus tests for commonly regulated transportation emissions including carbon monoxide, hydro-carbons, nitrogen oxides, and particulate matter. Carbon dioxide is also included to understand greenhouse gas emissions. A meta-analysis technique was used with 25 studies to find a range of emissions values for different fuel and exhaust after treatment combinations to determine which combinations provide the greatest emissions reduction. The fuels considered for this report are diesel with various concentrations of sulfur, biodiesel (100 percent and 20 percent blend with diesel), compressed natural gas, liquefied natural gas, and ethanol. The technologies considered are standard internal combustion engines, hybrid ICE-electric and a variety of exhaust after-treatment technologies. The analysis shows that no single fuel is best at reducing all emissions if the appropriate exhaust after-treatment technologies are used. The technologies which show the lowest emissions in important categories, NOx, PM, and CO2 equivalents, are compressed natural gas with a three-way catalyst, 100 percent biodiesel, and ultra-low sulfur diesel with selective catalyst reduction. Other factors explored, such as altitude, drive cycle, and mileage, also have an impact on emissions values. Overall, there is a wide range of emissions values even for the same fuel and technology. These variations and factors should be understood in order to accurately evaluate results from further emissions testing.
  Authors: Cooper, Erin; Arioli, Magdala; Carrigan, Aileen; Jain, Umang
  Authors: Cooper, Erin; Arioli, Magdala; Carrigan, Aileen; Jain, Umang
  Year: 2013
  Document Type: Paper
  Subject: Environment; Public Transportation
  Session: 585
  Paper Number: 13-4618
  Practice-Ready: Yes
• Statistical Study of Variables Associated with Particulate Matter Exposure Levels at Bus Shelters
  Authors: Moore, Adam
  Authors: Moore, Adam
  Year: 2013
  Document Type: Presentation
  Subject: AICP Certification Maintenance Session; Environment; Public Transportation
  Session: 585
  Paper Number: 13-2845
• Air Quality Regulation in Metros: Benchmarking Approach
  Authors: Cohen, Judith
  Authors: Cohen, Judith
  Year: 2013
  Document Type: Presentation
  Subject: AICP Certification Maintenance Session; Environment; Public Transportation
  Session: 585
  Paper Number: 13-2476
• Meta-analysis of Transit Bus Exhaust Emissions
  Authors: Cooper, Erin
  Authors: Cooper, Erin
  Year: 2013
  Document Type: Presentation
  Subject: AICP Certification Maintenance Session; Environment; Public Transportation
  Session: 585
  Paper Number: 13-4618
• Idle Monitoring, Real-Time Intervention, and Emission Reductions from School Buses in Cobb County, Georgia
  Authors: Xu, Yanzhi
  Authors: Xu, Yanzhi
  Year: 2013
  Document Type: Presentation
  Subject: AICP Certification Maintenance Session; Environment; Public Transportation
  Session: 585
  Paper Number: 13-4964