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.
The PEM hydrogen fuel cell produces zero emissions. If supplied with Pure hydrogen and Oxygen from the air it will produce heat, water and electricity. Hydrogen does not exist freely on Earth. Most hydrogen is made from fossil fuels: