For years, noisy -- and pollution-spewing -- leaf blowers have served as a source of morning aggravation and have spawned endless quarrels among neighbors. But now, in response to a flurry of new ordinances restricting the gadgets' use, leaf-blower makers are bringing out quieter and more fuel-efficient models.

Manufacturers are introducing blowers that operate at noise levels between 65 and 70 decibels as opposed to older models that operate at 70 decibels or higher. They are also rolling out products with lower emissions...