Human-Produced Aerosols in Many Arctic Clouds Contribute to Climate Warming
SatCon Wins Army Contract for Integrated Starter/Generator for Hybrids

Connecticut DEP Presents Clean Diesel Plan

Diesel Particulate Matter (DPM). Source: CT DEP

The Connecticut Department of Environmental Protection (DEP) has presented a Clean Diesel Plan to the state General Assembly that would significantly reduce the emissions of PM 2.5 diesel particulate matter from buses and construction equipment.

The DEP developed the plan in response to Special Act 05-7 of the General Assembly which required DEP to provide the legislature with a strategy to reduce health risks associated with diesel emissions from four specific sectors: transit, school bus, construction, and on-road fleets.

The DEP concluded it would cost approximately $20 million to retrofit or replace transit buses, school buses and construction equipment to meet the specific targets for diesel emissions reductions suggested in the 2005 legislation. These targets were:

  • 85% reduction of diesel particulate matter in transit buses by the end of 2010.

  • Maximized reduction of diesel particulate matter and prevent diesel emissions from entering the passenger cabins of buses by the end of 2010.

  • Maximize the reduction of particulate matter emissions from construction equipment servicing state construction projects valued at more than $5 million by 1 July 2006.

Sources of Connecticut on-road PM 2.5 emissions in 2002. Click to enlarge.

In 2002, highway vehicles in Connecticut emitted 563 tons of PM 2.5 (about 2.7% of the total 21,000 tons of PM emitted from all sources). Of that highway total, school and transit buses accounted for 6%, or 33.78 tons per year. Heavy-duty Class 8 trucks accounted for 69%.

The report steps back from suggesting a strategy for on-road fleet reductions (i.e., those of heavy-duty commercial diesel vehicles).

The current inventory [of suggested approaches] is somewhat limited to develop detailed evaluation of fleet-wide emission reduction options. Prior to developing fleet specific emission reduction strategies and choosing an appropriate model for Connecticut, a complete inventory of on-road vehicles is needed...

In its development of a more detailed on-road action plan, DEP will focus on the waste-hauling fleet because:

  • The trucks travel at low speed and idle frequently in neighborhoods and commercial centers directly exposing people to their exhaust;

  • They operate in significant numbers in urban areas where diesel emission reductions should be prioritized; and

  • They are likely to be either publicly owned or privately owned but under public contract.

The DEP report also suggests that the legislature consider steps to reduce diesel emissions in areas beyond the mobile sources specified in its Special Act of 2005. These include:

  • Consider the use of low sulfur and biodiesel blended home heating oil. Reducing the permitted sulfur content of heating oil from 3,000 parts per million (ppm) to 500 ppm would reduce sulfur emissions by 83 percent. The agency also said further reductions could be obtained by requiring a blend of low-sulfur heating oil and biodiesel fuel.

  • Address emissions from wood burning. While not directly related to diesel emissions, wood burning is a major source of the type of particulate pollution addressed by the Special Act, representing an estimated 38% of fine particulate matter (PM 2.5) in the state’s air. As fuel prices rise, more people are burning wood as a primary source of fuel.

  • Develop a more comprehensive anti-idling strategy. While there are anti-idling laws for school buses, broader legislative and legal enforcement action—including strong penalties for violations—is needed to reduce excessive idling by all types of motor vehicles, according to DEP.

  • Encourage fleet turnover. Tax incentives could be considered to encourage the earlier retirement and replacement of older buses, which would speed up air quality benefits of the new engines beginning with the 2007 model year.

Emissions from diesel engines contain fine particulate matter (PM 2.5). Exposure to PM 2.5 has been linked to premature death from heart or lung disease. When inhaled into the lungs it can aggravate existing heart and lung diseases to cause cardiovascular symptoms, arrhythmias, heart attacks, chronic obstructive pulmonary disease, asthma attacks and bronchitis. EPA has also classified Diesel Particulate Matter as a probable human carcinogen.

Children, the elderly, and other sensitive populations are most at risk from diesel emissions and PM 2.5. Urban areas, with construction sites and heavy traffic that includes buses and diesel trucks, are often hot spots for PM 2.5, which puts large numbers of people at risk.

Public exposure to PM 2.5 is a health issue in Connecticut and states across the country. The EPA has formally designated New Haven and Fairfield Counties as being in non-attainment with the federal ambient air quality standard for PM 2.5.

Approximately one half of the state’s population (1.73 million people) resides in these two counties. In addition, the entire state fails to meet federal ozone standards.




We presently have the technology to meet our 2010 goals. Connecticut has formed this proactive approach to emissions reduction with support from industry & business. The real challenge is to meet the goals without unequal economic burden to a partilcuar business segment. We cannot afford to legislate a better environment and drive business & jobs out of our state.

The comments to this entry are closed.