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ARB Study: West Oakland, CA Community Exposed to Diesel PM 3X Average in Bay Area
24 March 2008
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| Estimated potential cancer risk in the regional domain from port diesel PM emissions sources. Click to enlarge. |
Residents of the West Oakland, California area are exposed to diesel PM ambient concentrations that are almost three times the average background diesel PM ambient concentrations in the Bay Area Air Quality Management District, according to a comprehensive health risk assessment study released by the California Air Resources Board (ARB).
The diesel particulate matter emissions from trucks traveling on nearby freeways and marine vessel traffic in the San Francisco Bay Area unrelated to the Port of Oakland are causing an increased potential cancer risk to the West Oakland community.
The study, developed in collaboration with the Bay Area Air Quality Management District, the Maritime Port of Oakland and Union Pacific (UP) Railroad, reveals that the estimated lifetime potential cancer risk for residents of West Oakland from exposure to diesel emissions is about 1,200 excess cancers per million people. The analysis covers 3.1 million people who reside in the affected area of 3,800 square miles.
The estimate assumes residents are exposed to the year 2005 levels of diesel PM emissions (Port and UP operations, and non-Port/non-UP marine and land-based diesel sources) continuously for 70 years.
While diesel trucks account for a majority of the risk in West Oakland resulting in about 850 potential cancer cases per million or 70%, port operations account for an estimated lifetime potential cancer risk of 200 excess cancer cases per million, or about 15% of the total. Union Pacific railyard emissions amount to a potential cancer risk of about 40 excess cancer cases per million, or less than 5% and the remaining 10% of risk comes from a variety of diesel sources such as passenger trains and construction projects.
On a regional basis, diesel PM emissions from Port operations impact a very large area—about 550,000 acres, with a population of more than 3 million people. As a result of the diesel PM emissions from the Port, the population has potential elevated cancer risks of more than 10 chances in a million. Overall, the Port emissions result in a regional population-weighted potential cancer risk of about 27 in a million. Ocean-going vessels (OGV) emissions are the largest contributor to the regional risk due to Port-related activities, responsible for about 85% of overall average potential cancer risks.
In the development of the ship emissions, ARB staff used transponder data to more accurately estimate where off-shore emissions are occurring. For the first time in a large risk assessment, a regional wind field was generated using data from 30 onshore and 3 offshore weather stations. The CALPUFF model was used to estimate the ambient concentration of diesel particulate matter. This model is capable of producing more precise results than the models used in the past due to its ability to account for highly varying wind fields and complex terrain.
Emissions from diesel particulate matter are associated with causing a variety of health effects including premature death and a number of heart and lung diseases. The study also estimates the yearly non-cancer health impacts resulting from exposure to port-related diesel particulate matter emissions in the area: 18 premature deaths (age 30 and older), 290 asthma attacks, 2,600 days of work loss, and 15,000 minor restricted activity episodes.
Later this year, ARB will be considering proposed regulations involving on-road heavy duty diesel vehicles (trucks and buses) and ocean-going vessel main engines to further reduce diesel soot. State control measures will contribute to an approximate decrease of 80% in harmful emissions by 2015.
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March 24, 2008 in Diesel, Emissions | Permalink | Comments (4) | TrackBack (0)
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Comments
I think people forget that West Oakland not only has a lot of truck traffic, but also a lot of train traffic and ship traffic, all with ships and locomotives powered by diesel engines. However, with the railroads switching to at least Tier 2-compliant locomotives at the railyards in West Oakland and the upcoming standards for diesel-powered ships in US waters, the diesel particulate problem should drop quite a bit (and will drop even more when trucks switch to engines with particulate traps over the next 4-5 years.
Posted by: Raymond | Mar 24, 2008 6:19:19 PM
Lets see...70% trucks,15% port ops,5%? rail yard,10% trains and construction. Dosent that add up to near 100% excluding ANY diesel cars? So North America has virtually NO diesel cars because CARB cant add?
Gee, imagine if we werent exporting diesel fuel, making something approaching 50 Cetane and lowering sulpher in everything.
Posted by: fred | Mar 24, 2008 9:49:10 PM
@Fred -
thanks to extremely strict emissions regs for passenger cars and light trucks, the number with diesel engines on California's roads today is negligible.
Medium and heavy duty truck emissions regs are not as strict, so diesels can be used instead. Continuously regenerating traps and urea injection, in combination with ULSD, will sharply reduce emissions from these vehicles as their fleet churns or retrofit programs are enacted.
The Port of Oakland is already busy cleaning up its act:
http://www.epa.gov/diesel/ports/casestudies.htm
http://news.thomasnet.com/companystory/529069
As for rail yard and freight diesel locomotives as well as local ferries and construction equipment, existing ones can be retrofitted with CRTs and urea injection now that ULSD is available. The transition will take considerable time, though.
Ocean-going ships, especially those sailing under foreign flags, will eventually also have to use at least low-sulfur fuel within US territorial waters (out to 24 nautical miles). The main issue is limited availability of this fuel grade in Asia.
Posted by: Rafael Seidl | Mar 24, 2008 11:53:11 PM
Rafael,
There is an article in today's Sacramento Bee talking about a company testing a retrofit system that essentially is an industrial version of the BlueTec system developed by Mercedes-Benz. Despite its fairly steep cost (US$25,000 per truck), the resulting emission levels are lower than CARB requirements for commercial trucks starting in 2011!
Posted by: Raymond | Mar 25, 2008 6:14:22 PM
