• Print

    Memphis transit buses burning cleaner after diesel-retrofit project

    Tom Charlier
    At a time when private vehicles are getting a free pass on emissions inspections, Shelby County is moving to sharply reduce the amount of pollution spewed by government-owned diesel buses and trucks rolling down local roads.
    The county recently completed a project that retrofitted 60 older-model Memphis Area Transit Authority buses with equipment designed to restrict emissions of hydrocarbons, particulate matter and carbon monoxide. The initiative follows similar improvements made to 85 garbage trucks in 2008 and 250 school buses in 2011.
    The latest initiative cost $659,046 — or a little over $10,000 and six to eight hours of work per bus. It entailed the installation of diesel particulate filters and closed-crankcase ventilation systems. The filters resemble mufflers and screen out the tiniest of lung-penetrating soot particles, while the ventilation systems recirculate engine oil and fumes that otherwise would be spit into the air.
    Money for the work came from a federal Congestion Mitigation and Air Quality Improvement grant secured by the Health Department. It’s the first time the so-called CMAQ program has funded work in Tennessee to install diesel-retrofit technology, according to local officials.
    The filters and ventilators will cut emissions of hydrocarbons by 85 percent, carbon monoxide by 75 percent and particulate matter by 90 percent, health officials say. Hydrocarbons react to form ozone pollution, while microscopic particulate matter, or soot, can penetrate deep into the lungs.
    “So much of the danger from diesel is the (particulate matter) that you can’t see,” said Larry J. Smith, supervisor of the Health Department’s air-quality improvement branch, which oversaw the retrofitting.
    The pollution reductions from the project are significant, Smith added.
    The 60 buses were the oldest among MATA’s fleet of about 200 vehicles. They were chosen for the retrofitting work because newer models are far less polluting than older ones.
    “For years MATA helped the environment by giving riders an alternative to putting a car on the road. Now MATA buses themselves can help by creating less pollutants,” MATA interim president and general manager Tom Fox said in a prepared statement.
    The improvements to diesel vehicles follow the shutdown last year of a vehicle-inspection program that checked the emissions of cars and trucks registered in Memphis. County officials acknowledge that the program’s demise — the result of a cost-cutting decision by the city of Memphis — could lead to a modest increase in vehicle pollution.