Gas detector in industrial refrigeration processes and biological degradation processes, including exhaled breath. Depending on the required sensitivity, different types of sensors are used (e.g., flame ionization detector, semiconductor, electrochemical, photonic membranes). Detectors usually operate near the lower exposure limit of 25ppm; however, ammonia detection for industrial safety requires continuous monitoring above the fatal exposure limit of 0.1%. There are several different sensors that can be installed to detect hazardous gases in a residence. Carbon monoxide is a very dangerous, but odorless, colorless gas, making it difficult for humans to detect. Carbon monoxide detectors can be purchased for around US$20–60. Many local
Natural gas in China Natural gas in China Over the last five years, gas consumption, production, and imports in China have grown dramatically, with two-digit growth. Considering China's immense demand for energy, gas plays a relatively small role in its energy use, with only 5% of total energy in 2012. However, Chinese authorities see natural gas as a lower-polluting and less carbon-intensive alternative to coal, and gas consumption is increasing rapidly. Natural gas is expected to supply 10% of the nation’s energy supply by 2020. China produced 112 billion cubic meters of natural gas in 2013, making it the sixth largest gas producer in