Climate change in Washington related emissions are the dominant source of GHG emissions and have increased from 61.2 MMT CO-equivalent (CO-e) in 1990 (excluding residual fuel for transportation) to 74.6 MMT CO-e in 2004, while their share has increased from 79% of total emissions to 85% over the past fourteen years. Carbon dioxide is the dominant GHG followed by methane, nitrous oxide, perfluorocarbon and sulfur hexafluoride. Non-energy industrial global greenhouse gas emissions have lowered from 14% to 9%, mainly due to reduced emissions from aluminum production. This has been the result of two key elements: process changes that reduced CO and PFC emissions per
Nitrous oxide aid responders in prehospital settings, given the relative ease and safety of administering 50% nitrous oxide as an analgesic. The rapid reversibility of its effect would also prevent it from precluding diagnosis. Recreational inhalation of nitrous oxide, with the purpose of causing euphoria and/or slight hallucinations, began as a phenomenon for the British upper class in 1799, known as "laughing gas parties". Starting in the nineteenth century, widespread availability of the gas for medical and culinary purposes allowed the recreational use to expand greatly, throughout the world. In the United Kingdom, as of 2014, nitrous oxide was estimated to be