16 research outputs found
Alkaline air: changing perspectives on nitrogen and air pollution in an ammonia-rich world
Ammonia and ammonium have received less attention than other forms of air pollution, with limited progress in controlling emissions at UK, European and global scales. By contrast, these compounds have been of significant past interest to science and society, the recollection of which can inform future strategies. Sal ammoniac (nĆ«shÄdir, nao sha) is found to have been extremely valuable in long-distance trade (ca AD 600â1150) from Egypt and China, where 6â8âkgâN could purchase a human life, while air pollution associated with nĆ«shÄdir collection was attributed to this nitrogen form. Ammonia was one of the keys to alchemyâseen as an early experimental mesocosm to understand the worldâand later became of interest as âalkaline airâ within the eighteenth century development of pneumatic chemistry. The same economic, chemical and environmental properties are found to make ammonia and ammonium of huge relevance today. Successful control of acidifying SO2 and NOx emissions leaves atmospheric NH3 in excess in many areas, contributing to particulate matter (PM2.5) formation, while leading to a new significance of alkaline air, with adverse impacts on natural ecosystems. Investigations of epiphytic lichens and bog ecosystems show how the alkalinity effect of NH3 may explain its having three to five times the adverse effect of ammonium and nitrate, respectively. It is concluded that future air pollution policy should no longer neglect ammonia. Progress is likely to be mobilized by emphasizing the lost economic value of global N emissions ($200 billion yrâ1), as part of developing the circular economy for sustainable nitrogen management
1TBulk eDRAM Using Gate-Induced Drain-Leakage (GIDL) Current for High Speed and Low Power applications
International audienc