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.
A concept like vegetable oil economy produces emissions; however, the only emissions are things that were first taken out of the atmosphere when the plants were growing. So there is no net emission. The same concept can also be applied to similar fuels such as nitrous oxide and syngas.