Massachusetts Vehicle Check - Mass08 Management Module ...

Non-Commercial
weather combined with hydrocarbons (HC) and nitrogen oxides (NOx) cause ground level
ozone to form in harmful concentrations. As a result, it is known as a summertime air
pollutant. Many urban areas tend to have high levels of "bad" ozone, but even rural areas are
subject to increased ozone levels because wind carries ozone and the pollutants that form it
hundreds of miles away from their original sources.
Ground-level ozone can reduce lung function and inflame the linings of the lungs.
Repeated exposure may permanently scar lung tissue. People with lung disease, children,
older adults, and people who are active can be affected when ozone levels are unhealthy.
Particulates
Particulate matter (dust, soot, and other aerated solid materials) are also released into
the air by combustion. These particles can damage the lungs and cause other health problems.
Emission Control Systems And Devices
Emission control devices dating back to the 1960s, included such devices as positive
crankcase ventilation valve (PCV); thermostatic air cleaner; fuel filler neck restrictor; and
charcoal canister. As emissions systems evolved and standards were tightened, the need for
other emission control devices was mandated to meet the federal requirements. The new
standards led the way for the development of other emission control devices, such as air
injection reaction systems (AIR); exhaust gas recirculation valve (EGR); spark control
devices, and catalytic converters. Modern computerized vehicles have enabled the on-board
computer (PCM) to test the vehicle’s emission control devices to ensure they are performing
as designed.
Massachusetts Vehicle Check
Ch. 1 - 6