Using new technology, clean coal plants sharply reduced the number of sooty particles spewed into the air, as well as gases like sulfur dioxide and nitrous oxide.
使用新技术，清洁煤电厂大大减少了煤烟粒子散发到大气中的数量，以及像二氧化硫和一氧化氮等气体。
2
The nitrous-powered rocket's only byproduct is hot, pure air.
氧化氮动力火箭排出的副产品只不过是纯净的热气体。
3
Run-off from animal manure also fouls watercourses, and the release of nitrous oxides from uncovered dung heaps pollutes the air.