National Academies Press: OpenBook

Handbook on Applying Environmental Benchmarking in Freight Transportation (2012)

Chapter: Chapter 2 - Air Quality and Climate Change Impacts of Freight Transportation

« Previous: Chapter 1 - Introduction
Page 2
Suggested Citation:"Chapter 2 - Air Quality and Climate Change Impacts of Freight Transportation." National Academies of Sciences, Engineering, and Medicine. 2012. Handbook on Applying Environmental Benchmarking in Freight Transportation. Washington, DC: The National Academies Press. doi: 10.17226/22668.
×
Page 2
Page 3
Suggested Citation:"Chapter 2 - Air Quality and Climate Change Impacts of Freight Transportation." National Academies of Sciences, Engineering, and Medicine. 2012. Handbook on Applying Environmental Benchmarking in Freight Transportation. Washington, DC: The National Academies Press. doi: 10.17226/22668.
×
Page 3
Page 4
Suggested Citation:"Chapter 2 - Air Quality and Climate Change Impacts of Freight Transportation." National Academies of Sciences, Engineering, and Medicine. 2012. Handbook on Applying Environmental Benchmarking in Freight Transportation. Washington, DC: The National Academies Press. doi: 10.17226/22668.
×
Page 4
Page 5
Suggested Citation:"Chapter 2 - Air Quality and Climate Change Impacts of Freight Transportation." National Academies of Sciences, Engineering, and Medicine. 2012. Handbook on Applying Environmental Benchmarking in Freight Transportation. Washington, DC: The National Academies Press. doi: 10.17226/22668.
×
Page 5
Page 6
Suggested Citation:"Chapter 2 - Air Quality and Climate Change Impacts of Freight Transportation." National Academies of Sciences, Engineering, and Medicine. 2012. Handbook on Applying Environmental Benchmarking in Freight Transportation. Washington, DC: The National Academies Press. doi: 10.17226/22668.
×
Page 6

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

2C h a p t e r 2 Air pollution from freight transportation is a public health issue of concern in communities and regions in the United States and around the world. Diesel-powered equipment is the most important source of air emissions associated with freight transport. Air emissions from freight facilities and equipment powered by other fuels are also discussed in the handbook. Air emis- sions can be separated into three primary pollutant categories: criteria pollutants, greenhouse gases, and air toxics. Each of these is described in detail below. 2.1 Criteria Air Pollutants Criteria air pollutants (CAPs) are those for which either the federal government and/or the California State government have established ambient air quality standards based on short- and/ or long-term human health effects. The federal government, via the U.S. Environmental Pro- tection Agency (EPA) has established national ambient air quality standards (NAAQS) for the following six pollutants: ground-level ozone (O3), carbon monoxide (CO), particulate matter (PM) less than 10 (PM10) and 2.5 microns (PM2.5), nitrogen dioxide (NO2), sulfur dioxide (SO2), and lead (Pb). Although they are not a criteria pollutant, volatile organic compounds (VOCs) are often con- sidered along with criteria pollutants because they are chemical precursors for ground-level ozone. Depending on the report or methodology, these gases are referred to in the following various forms: • Reactive organic gases (ROG), • Total organic gases (TOG), • Hydrocarbons (HC), • Total hydrocarbons (THC), • Non-methane hydrocarbons (NMHC), and • Diesel exhaust organic gases (DEOG). Although each term defines specific subsets of VOCs, references to these terms in various methodologies all refer to the same class of VOC pollutants. The major criteria pollutants and freight transportation’s contribution to emissions are discussed below. • Ozone, which is a product of reactions involving NOx and VOCs, can aggravate asthma and other respiratory diseases, leading to more asthma attacks, visits to the emergency room, and increased hospitalizations. Sunlight breaks down the precursor pollutants NOx and VOCs. The oxygen atoms then recombine to form ozone. Ozone formation is thus greatest during the Air Quality and Climate Change Impacts of Freight Transportation

air Quality and Climate Change Impacts of Freight transportation 3 summer months when there is more and stronger sunlight. Ozone can inflame and damage the lining of the lungs. This may lead to permanent changes in lung tissue and to irreversible reductions in lung function if the inflammation occurs repeatedly over a long time period. Children, the elderly, and people with heart and lung disease are most at risk. Wind cur- rents can transport ozone and ozone precursors for many miles. Major freight facilities that have congested operations during the day can be significant contributors to ozone formation. There are no reliable estimates for determining the proportion of ozone attributable to freight transportation, but diesel engines are a significant source of NOx, which is an ozone precursor. • Oxides of Nitrogen (NOx) form a group of highly reactive gasses that are also called “nitrogen oxides” (NOx) and include nitrogen dioxide (NO2). NO2 is the component of greatest interest, and it serves as an indicator for the larger group of nitrogen oxides. In addition to contributing to the formation of ground-level ozone and fine particle pollution, NO2 is linked to a number of adverse effects on the respiratory system. Current scientific evidence links short-term NO2 exposures, ranging from 30 minutes to 24 hours, with adverse respiratory effects, including airway inflammation in healthy people and increased respiratory symptoms in people with asthma. Freight transportation accounts for approximately half of mobile source NOx emis- sions and 27 percent of NOx emissions from all sources.1 Exhibit 1 shows the breakdown of NOx emissions for all mobile sources. • Particulate matter (PM) is a complex mixture of extremely small particles and liquid drop- lets. PM is made up of a number of components, including acids (such as nitrates and sul- fates), organic chemicals, metals, and soil or dust particles. The size of particles is directly linked to their potential for causing health problems. EPA is concerned about particles that are 10 micrometers in diameter or smaller because those are the particles that generally pass through the throat and nose and enter the lungs. Once inhaled, these particles can affect the heart and lungs and cause serious health effects. EPA groups particle pollution into two categories: inhalable course particles and fine particles. Inhalable coarse particles, such as those found near roadways and dusty industries, are larger than 2.5 micrometers and smaller than 10 micrometers in diameter, and referred to as PM10. The transportation sector, which includes road dust, is responsible for approximately 54 percent of Source: 2009 National Emissions Inventory On-road passenger emissions 32% Medium and Heavy Duty Trucks 36% Ships and Boats 7% Rail 6% Aircraft >1% Other 19% Exhibit 1. Mobile source NOx emissions. 1U.S. Department of Transportation, Federal Highway Administration. “Assessing the Effects of Freight Movement on Air Quality at the National and Regional Level.” (Washington, D.C.: 2005), http://www.fhwa.dot.gov/ environment/air_quality/publications/effects_of_freight_movement/, downloaded September 12, 2011.

4 handbook on applying environmental Benchmarking in Freight transportation PM10 emissions. Freight movement produces approximately half of these emissions, with marine vessels accounting for 29 percent of transportation emissions, heavy-duty trucks creating 17 per- cent, and locomotive emissions creating 5 percent. See Exhibit 2. Fine particles, such as those found in smoke and haze, are up to 2.5 micrometers in diameter and are referred to as PM2.5. These particles can form when gases emitted from power plants, industry, and automobiles react in the air. PM2.5 has been associated with an increased risk of premature mortality, hospital admissions for heart and lung disease, and increased respiratory symptoms. There is significant evidence that PM2.5 emissions are more dangerous to human health because they can be transported in the air for longer distances, tend to remain in the lungs, and can enter the bloodstream. Fine particles are mostly created through the interac- tion of diesel exhaust particles with NOx. Mobile sources (including rail and marine) create approximately 10 percent of PM2.5 emissions. Road dust makes up an additional 21 percent of PM2.5 emissions. 2 • Oxides of Sulfur (SOx) form a group of highly reactive gasses that includes sulfur dioxide (SO2). The largest sources of SO2 emissions are from fossil fuel combustion at power plants (73 percent) and other industrial facilities (20 percent). The burning of high sulfur containing fuels by locomotives, large ships, and non-road equipment is also an important source of SOx. SO2 can combine with water vapor in the air to create acid rain. In addition, SO2 is linked with a number of adverse effects on the respiratory system.3 • Lead is a metal found naturally in the environment as well as in manufactured products. The major sources of lead emissions have historically been fuels for on-road motor vehicles (such as cars and trucks) and industrial sources. As a result of EPA’s regulatory efforts to remove lead from gasoline for on-road motor vehicles, emissions of lead from the transportation sec- tor dramatically declined by 95 percent between 1980 and 1999, and levels of lead in the air decreased by 94 percent between 1980 and 1999. The major sources of lead emissions to the Source: 2005 National Emissions Inventory Heavy-duty trucks 57% Marine 34% Railroads 9% Air 0% Exhibit 2. PM10 emissions from freight sources. 2Freight and Air Quality Handbook. U.S. Department of Transportation, Federal Highway Administration. http://ops.fhwa.dot.gov/publications/fhwahop10024/sect2.htm 3Sulfur Dioxide. U.S. EPA. http://www.epa.gov/air/sulfurdioxide/

air Quality and Climate Change Impacts of Freight transportation 5 air today are ore and metals processing and piston-engine aircraft operating on leaded avia- tion gasoline.4 • Carbon Monoxide (CO) is a colorless, odorless gas emitted from combustion processes. Nationally, and particularly in urban areas, the majority of CO emissions to ambient air come from mobile sources. CO can cause harmful health effects by reducing oxygen delivery to the body’s organs (like the heart and brain) and tissues. Goods movement activities, and diesel engines emissions specifically, are not significant sources of CO emissions.5 2.2 Greenhouse Gases Carbon dioxide (CO2), the primary greenhouse gas (GHG) associated with combustion of diesel (and other fossil fuels), accounts for over 95 percent of the transportation sector’s global warming potential-weighted GHG emissions. Methane (CH4) and nitrous oxide (N2O) together account for about 2 percent of total GHG emissions from the transportation sector. Both gases are released during fuel consumption (although in much smaller quantities than CO2) and are also affected by vehicle emissions control technologies. Hydrofluorocarbons (HFCs) are the result of leaks and end-of-life disposal of vehicle air conditioners used to cool freight and people. HFCs comprise approximately 3 percent of total transportation GHG emissions. Exhibit 3 reports GHG emissions by U.S. transportation source in CO2 equivalent units. This metric combines CO2 with all other major transportation GHG emissions (CH4, N2O, and Source: U.S. Greenhouse Gas Inventory, EPA Passenger Cars 35% Light-Duty Trucks 30% Medium- and Heavy-Duty Trucks 20% Aircraft 8% All Other Transportation Sources 6% Ships and Boats 2% Exhibit 3. GHG emissions from U.S. trans portation sources. 4Lead. U.S. EPA. http://www.epa.gov/airquality/lead/ 5Carbon Monoxide. U.S. EPA. http://www.epa.gov/airquality/carbonmonoxide/

6 handbook on applying environmental Benchmarking in Freight transportation HFCs). It converts other GHGs into units of CO2 equivalent based on their global warming potential. The exhibit shows that freight-related emissions are a significant share of all transpor- tation GHG emissions. Medium- and heavy-duty trucks are the largest source of GHG emissions associated with freight transportation. 2.3 Air Toxics Air toxics, also known as hazardous air pollutants (HAPs), toxic air contaminants (TACs), mobile source air toxics (MSATs), and non-criteria air pollutants (NCAPs), are contaminants found in ambient air that are known or suspected to cause cancer, reproductive effects, birth defects, other health effects, or adverse environmental effects, but do not have established ambi- ent air quality standards. HAP pollutants broadly fall into two categories—heavy metals and hydrocarbons—and are often calculated as a fraction of PM and VOC emissions. HAPs may have short-term and/or long-term exposure effects. EPA currently has implemented programs to reduce emissions of 188 HAPs; however, 1,033 total HAPs are listed by EPA as related to mobile source emissions. Of these, 644 are components of diesel exhaust, including benzene, cadmium, formaldehyde, and 1,3-butadiene. For freight transportation, the toxic air contami- nant of primary concern is typically diesel particulate matter; however, there are currently no specific annual limits on diesel particulate matter.

Next: Chapter 3 - Environmental Benchmarking: Overview of the Process and Benefits »
Handbook on Applying Environmental Benchmarking in Freight Transportation Get This Book
×
 Handbook on Applying Environmental Benchmarking in Freight Transportation
MyNAP members save 10% online.
Login or Register to save!
Download Free PDF

TRB’s National Freight Cooperative Research Program (NFCRP) Report 21: Handbook on Applying Environmental Benchmarking in Freight Transportation explores how benchmarking can be used as a management tool in the freight and logistics industry to promote environmental performance.

The report provides a step-by-step overview of the benchmarking process and describes a framework for applying this process to freight carriers, shippers, and freight hubs.

READ FREE ONLINE

  1. ×

    Welcome to OpenBook!

    You're looking at OpenBook, NAP.edu's online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

    Do you want to take a quick tour of the OpenBook's features?

    No Thanks Take a Tour »
  2. ×

    Show this book's table of contents, where you can jump to any chapter by name.

    « Back Next »
  3. ×

    ...or use these buttons to go back to the previous chapter or skip to the next one.

    « Back Next »
  4. ×

    Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

    « Back Next »
  5. ×

    To search the entire text of this book, type in your search term here and press Enter.

    « Back Next »
  6. ×

    Share a link to this book page on your preferred social network or via email.

    « Back Next »
  7. ×

    View our suggested citation for this chapter.

    « Back Next »
  8. ×

    Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

    « Back Next »
Stay Connected!