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 Thomas Clover invented the "gas-ether inhaler" in 1876, however, it became a common practice at hospitals to initiate all anaesthetic treatments with a mild flow of nitrous oxide, and then gradually increase the anaesthesia with the stronger ether or chloroform. Clover's gas-ether inhaler was designed to supply the patient with nitrous oxide and ether at the same time, with the exact mixture being controlled by the operator of the device. It remained in use by many hospitals until the 1930s. Although hospitals today are using a more advanced anaesthetic machine, these machines still use the same principle launched with Clover's