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 struggling to implement and maintain compliance with 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 about the health effects of ultrafine particles and a significant fraction of the Center's resources is directed at airborne particles, their generation, the attribution of their sources from ambient measurements, and their chemical and physical behavior in the atmosphere. 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 billions of dollars over the past two decades. Dealing with air toxics presents many challenges in defining the magnitude of the problem posed by the many chemicals listed in the CAAA and establishing priorities for their control. Ultrafine carbonaceous particles continue to be 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 which emit them (or their chemical precursors) are also numerous and include natural processes as well as anthropogenic activities. Progress has been made in understanding the quantity and composition of material emitted by familiar sources such as cars, but much work remains to be done. Once emitted, material may change chemically or physically in the atmosphere, further complicating the task of matching airborne pollutants and their source(s). 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 activities: