Clean Air :- What More Can Be Done?

What More Can Be Done?
The 1990 Clean Air Act requires EPA to specifically regulate air toxics from
motor vehicles in the form of standards for fuels, or vehicles, or both.
Additional hydrocarbon and particulate matter controls such as tightening
tailpipe standards even further will reduce air toxics emissions somewhat.
California for example, sets tighter hydrocarbon limits for vehicles sold in
that state than the federal requirements for vehicles sold elsewhere. Other
states can choose to adopt the California standards, which provide some air
toxics benefits. Expansion of existing regulatory programs (such as more
widespread use of reformulated gasoline or wider requirements for emission
inspections) could also help reduce air toxics. Specific vehicle emission
standards for one or more toxic compounds are also an option.
Changes in gasoline and diesel fuel composition (such as reducing sulfur,
benzene or other aromatic chemical compounds) can also reduce air toxics
emissions.
A switch to alternative, non-petroleum fuels that are cleaner than today’s
gasoline and diesel fuels offers another strategy for reducing air toxics.
Choices include alcohols, natural gas, propane, and electricity. These fuels
are inherently cleaner than conventional gasoline and diesel because they do
not contain toxics such as benzene. In addition, they are made of simpler
chemical compounds which yield lower levels of complex combustion
by-products such as 1,3-butadiene.