The role of atmospheric processes in the global distribution of some persistent organochlorines
- Atompsheric and Environmental Research, Inc., Cambridge, MA (United States)
Persistent organochlorines are introduced into the troposphere by human activities such as pesticide use in agriculture, incineration of wastes, and land fill emissions. Their atmospheric distribution is controlled by the location of sources and removal mechanism such as reaction with OH, washout and adsorption to particulate matter and subsequent deposition by either gravitational settling or washout particles. Observation show large accumulation of these organochlorines at higher northern latitudes. It was suggested that this results from the sensitivity of adsorption and solubility coefficients of these compounds to temperature and is often called the distillation effect. We present a global scale coarse grid 3D-CTM simulation of transport and deposition of some of the semi-volatile organochlorines. Results from the simulation for the compounds {alpha}-HCH, {gamma}-HCH and other organochlorines will be presented. Temperature and transport parameters from the GISS GCM are used in the simulation. Pre-calculated OH loss rates. Washout is parameterized by scaling the organochlorine Henrys law solubility`s HNO{sub 3} washout rates. Background aerosol distributions over land and ocean surfaces with a prescribed vertical profile were used. Aerosol removal rates were set equal to HNO{sub 3} washout rates in the lower troposphere and of a month in the upper troposphere. The effectiveness of the distillation processes in transporting these organochlorines to a higher latitudes will be discussed. Model predicted concentrations in the gas phase and rainwater will be compared with available observations.
- OSTI ID:
- 466253
- Report Number(s):
- CONF-9606185-; TRN: 96:005931-0204
- Resource Relation:
- Conference: 5. international conference on atmospheric sciences and applications to air quality, Seattle, WA (United States), 18-20 Jun 1996; Other Information: PBD: 1996; Related Information: Is Part Of The 5th international atmospheric sciences and applications to air quality conference; PB: 322 p.
- Country of Publication:
- United States
- Language:
- English
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