The Center on Airborne Organics was established at the California Institute of Technology (Caltech), Massachusetts Institute of Technology (MIT), and New Jersey Institute of Technology (NJIT) to address air pollution problems. The nation is now struggling to implement the provisions of the Clean Air Act Amendments (CAAA) of 1990, particularly those targeted at controlling tropospheric ozone and air toxics. Increased concern is being expressed with the health effects of ultrafine particles and a significant fraction of the Center's resources is directed at fine particles, their generation, attribution of their sources from ambient measurements, and their effects. Costly emission control measures adopted to date have proved to be only partially successful in controlling ozone in urban areas. Ozone concentrations still exceed current standards in many areas despite the expenditures of many billion dollars over the past two decades. The problem of air toxics is one that is posing many challenges in defining the magnitude of the problem posed by the 189 chemicals listed in the CAAA and establishing priorities for their control. Tiny carbonaceous particles continue to decrease visibility and are implicated in human health effects There is, however, large uncertainty as to the size, composition, and source of the particles of concern to human health.
The reason it is so difficult to reduce atmospheric concentrations of organic pollutants is that the atmosphere contains an enormous variety of organic compounds with widely differing characteristics and impacts on health and the environment. The sources that emit them (or their chemical precursors) are also numerous and include natural processes as well as anthropogenic devices. The quantity and composition of material emitted even by familiar sources such as cars is unclear. And once emitted, material may change chemically or physically in the atmosphere, further complicating the task of matching airborne pollutant and source. Given such complexities and uncertainties, it is difficult to forecast how a given regulatory strategy will influence ambient air quality.
To support the policy making process, the Center on Airborne Organics
draws on the talents of recognized leaders at Caltech, MIT, and NJIT in
the areas of sources and control, transport and transformation, and
monitoring and source attribution to address the following interrelated