Twelve chemical plants in China and the United States emit a potent climate pollutant with collective emissions equal to the annual greenhouse gas emissions of 31 million cars, according to a report released Thursday by Global Efficiency Intelligence, a Tampa-based industrial decarbonization research and consulting firm. . The emissions, which also damage the Earth's protective ozone layer, could be effectively eliminated at low cost, the report's authors conclude. According to the report, 11 Chinese plants and one US factory emit a combined estimated total of about 500,000 metric tons of nitrous oxide (N2O). On a pound-for-pound basis, N2O is 273 times more potent a greenhouse gas than carbon dioxide, the main driver of climate change. The gas is an unwanted byproduct of the production of adipic acid, a key component of nylon 6,6, a high-strength plastic used in airbags and car tires. Nitrous oxide emissions are also a major and continuing source of ozone depletion in the atmosphere after more harmful chemicals were banned in recent decades under the Montreal Protocol, an international environmental agreement. (insideclimatenews, Phil McKenna)