1 Substance abuse. Abuse of drugs and alcohol can contribute to panic disorder.  Major life stress. Stressful events and major life transitions, such as the death of a loved one, can sometimes trigger panic attacks, which can potentially recur and go on to become panic disorder.
Zero emission refers to an engine, motor, process, or other energy source, that emits no waste products that pollutes the environment or disrupts the climate. Contents.
Diesel engines are more fuel-efficient than petrol/gasoline engines, but their NOx and particulate emissions cause problems, most notably in cities. Hybrid vehicles operating in electric-mode produce no pollution, which is good for city use. However, fuel efficiency on longer distances needs improvement.