Reducing smoke from heavy-duty vehicles is an important step in cleaning the air in Massachusetts. Emissions testing of diesel vehicles is the second phase of the Enhanced Emissions and Safety Test, which began in October 1999 with gasoline vehicle testing.
Diesel exhaust is an important source of air pollution.
The cars, trucks and buses we drive generate about 40 percent of our air pollution. One way to reduce this source of air pollution is by testing diesel exhaust and requiring vehicle owners to repair their vehicles where needed. Periodic emissions testing of diesel vehicles will ensure that diesel owners share responsibility with gasoline vehicle owners for cleaning the air we all breathe. Small particles found in diesel smoke are considered to be health hazards, particularly for children and the elderly. Increased lung disease and asthma rates have been associated with diesel pollution.