AMINO-ACID NITROGEN IN ATMOSPHERIC AEROSOLS - OCCURRENCE, SOURCES ANDPHOTOCHEMICAL MODIFICATION

The presence of amino acids in atmospheric precipitation and aerosols has been noted for many years, yet relatively little is known about th ese or other nitrogen containing organic compounds in the atmosphere. Marine and continental rainwater analyses indicate that atmospheric ae rosols, and subsequently atmospheric precipitation, may contain substa ntial levels of free and combined amino acids. The most likely source of amino N in the remote marine atmosphere appears to be the injection of proteinaceous material through the action of bursting bubbles at t he sea-air interface or the long range transport from terrestrial sour ces. The capacity of these substrates to undergo photooxidation and ph otodegradation in the atmosphere to simpler species, such as ammonium ions, carboxylic acids, and for the S containing amino acids, oxidized forms of sulfur, has received little attention from atmospheric chemi sts. The photochemistry of covalently bound amino groups, particularly as found in peptides and amino acids, is discussed here with the purp ose of summarizing what is known of their occurrence and their possibl e importance to atmospheric chemistry.