exhaust

When a plane passes through cold humid air, the contrails form as the vapour from the engines condenses on unburned fuel fragments in the exhaust stream.

Teachers, who don’t always qualify for state disability or pay during leave through the Family and Medical Leave Act, are instead expected to exhaust sick days, pay for their own substitutes, return to work before they’re fully healed or time our births with summer vacation.

Not long after its Proposition 65 designation, the California Air Resources Board classified diesel exhaust as a toxic air contaminant, enabling the agency to regulate it.

The study, conducted by Silent Spring and UC Berkeley researchers, suggests the law helped to reduce exposure to toxic substances commonly found in diesel exhaust and plastic materials.

They included several types of phthalates, chemicals used to make plastics flexible; chloroform, a toxic byproduct from disinfecting water with chlorine; and toluene, a hazardous substance found in vehicle exhaust.