DEQ=Department of Environmental Quality,
a state agency charged with monitoring environmental pollution and
discharges.In the case of automobiles,running the testing program that
monitors enforcement and testing of tailpipe emissions.In cities that
monitor such emissions,they usually have compliance programs that
involve testing vehicles to monitor compliance keeping levels of noxious
tailpipe gases to a minimum and ensuring compliance by refusing to
license such vehicles that do not meet an environmental quality
standard.Places like Los Angeles,CA and similar large cities have
similar programs to control smog densities within cities.