Field Studies
Ambient aerosol is a complicated mixture of particles emitted from various sources after atmospheric reactions. The aerosol makeup is dynamic, diverse, and largely depends on local emission profiles and meteorological conditions. To date, researchers in the field are still trying to obtain more information on the aerosol chemical and physical characteristics so that they can eventually appropriately identify the sources and effectively control air pollution problems.
· Ambient measurements
To better understand aerosol composition, chemical association, and size distribution, our group often takes portable ATOFMS’s on a field trip to take ambient measurements at various locations on the continental US, we’ve even loaded the instruments on ships and taken measurements in the open ocean. The ATOFMS detects aerodynamic diameter and chemical composition of individual particles and thus providse information on, but not limited to, major particle classes and chemical association, temporal variation of chemical classes, and particle size distribution. Being capable of providing high time resolution data, the ATOFMS can capture instantaneous ambient events that are sometimes challenging for other techniques to detect.
· Source Studies
Besides taking ambient measurements, we’ve also taken the ATOFMS to emission sources and collected data from specific source. These measurements provide mass spectral signatures for individual sources, which helps to build a library for source apportionments (please see source apportionment section for details).
· Future Developments
Recently deployed mobile laboratory was tested in an ambient field study in 2005 as immobile sampling platform. After simple modification, this mobile lab will enable us to make measurements on the street or freeway while chasing other vehicles. This type of study will provide further understanding to transformation of vehicular emissions.
Another type of ATOFMS which is smaller and lighter weight is being built and near completion. This ATOFMS will be deployed on aircraft in the near future and take measurements in the atmosphere, specifically clouds.
