Aerosol production and transformation: from sources to impacts
Event details
| Date | 22.07.2011 |
| Hour | 10:15 |
| Speaker | Julie Cozic |
| Location | |
| Category | Conferences - Seminars |
The atmosphere is known to consist of a gas mixture but it is also composed of a large quantity of micron-size and smaller particles in suspension. These are called aerosol particles. They originate from a wide variety of sources. They can be natural (sea salt dust volcanic ashes…) or anthropogenic (fossil fuel powered engines industry biomass burning etc.). They can be emitted by primary processes or can be formed secondary by the photochemical processing of gaseous precursors of either natural or anthropogenic origin into condensable material. They are composed of a wide variety of chemical compounds inorganic (e.g. SO42- NH4+ Cl- Mg2+ Fe Al) and organic (e.g. PAHs organic acids alkanes). Atmospheric aerosols have an important role in human health problems. They also play a major role in climate change by absorbing and scattering solar and infrared radiation referred to as the direct forcing. They can also indirectly influence climate by altering the microphysical properties of clouds. The quantitative impacts nevertheless are still highly uncertain.
Studying the chemical composition of aerosol particles is of major interest to provide information on the sources and processes that influence their behavior. Results obtained are essential in decision makings of air quality control strategies as well as on the understanding of the climate system. For instance the research program Particul’air (LGGE FR http://particulair.free.fr/) was conducted to study the chemical composition and specific tracers in nine rural sites in France and allow identifying the strong influence of biomass burning particularly in Alpine valleys. Another example that can illustrate the importance of studying aerosol is the research program CLACE (PSI CH http://aerosolforschung.web.psi.ch/Clace3_Page/Clace3_Page.htm) that have been conducted to study the formation of water droplets and thus the formation of clouds which have a strong impact on radiation climate budget. This presentation will show details of those studies to demonstrate how important it is to understand the evolution of aerosol particles from the time of emission through transport and transformations in order to assess the impacts they can have.
Links
Practical information
- General public
- Free
Contact
- Christina Treier