Science Daily December 7, 2020
Pre-industrial aerosol concentration and composition particles formed directly in the atmosphere from gaseous precursors, constitutes a large uncertainty in the anthropogenic radiative forcing. From their observations taken at the remote Nepal Climate Observatory Pyramid station at 5,079 m above sea level an international team of researchers (Finland, Italy, Switzerland, France, Estonia, USA – industry) shows that up-valley winds funnel gaseous aerosol precursors to higher altitudes. During this transport, these are oxidized into compounds of very low volatility, which rapidly form many aerosol particles. These are transported into the free troposphere, suggesting that the whole Himalayan region may act as an ‘aerosol factory’ and contribute substantially to the free tropospheric aerosol population. Aerosol production in this region occurs mainly via organic precursors of biogenic origin with little evidence of the involvement of anthropogenic pollutants. This process may have been one of the major sources that contributes to the upper tropospheric aerosol population during that time…read more. TECHNICAL ARTICLE