24 March 2006
Research at the Chemical Sciences Division has made new advances toward quantifying the amount of ozone that can be lost during nighttime chemical processes in the lower atmosphere. The work is described in a paper that is in press at Geophysical Research Letters.
Background: Tropospheric ozone, a common atmospheric pollutant, is produced during the day from the interaction of sunlight with anthropogenic nitrogen emissions. These same nitrogen emissions also destroy ozone in a series of chemical reactions that take place at night. The nocturnal loss depends largely on reactive intermediates containing oxygen derived from ozone, or "odd oxygen." A novel analysis of recent aircraft measurements of ozone and key nitrogen species yields a budget for nocturnal chemical ozone loss.
Significance: This work represents a major step in quantifying regional-scale ozone destruction. Tropospheric ozone concentrations depend critically on timing of anthropogenic emissions, aerosol abundance and composition, hydrocarbon emissions, seasonality and atmospheric mixing. The research contributes to objectives of the Air Quality Program within NOAA's Weather and Water Goal.