| According to the Clean Air Act, the establishment of priorities in air pollution control should be based on benefits to public health and welfare. In this context, a computer model called ORAM (Ozone Risk Assessment Model) was developed to evaluate the health-effects caused by ground-level ozone exposure. ORAM was coupled with Models-3/CMAQ the EPA state-of-art air quality model that produces the ozone concentration and allows the examination of various scenarios in which emission rates of ozone precursors (basically NOx and VOC) are varied. Given that ozone is a local and regional problem, ORAM allows the health evaluation for local, regional and continental scales. The principal analyses in ORAM are: exposure model performance evaluation, health-effects calculations (expected number of respiratory hospital admission), economic valuation, sensitivity and uncertainty analysis through a Monte Carlo simulation. To demonstrate the system's effectiveness, ORAM was applied to the East Tennessee region, and the entire ozone season was simulated for a base case (actual, typical emissions) and three different emission scenarios using an available hospital admission database. The results indicated that a synergism occurs when NOx emissions from mobile (50%) and point sources (70%) were simultaneously reduced. A 19% in reduction on hospital admission for respiratory diseases occurs when both mobile and point sources NOx emissions are reduced versus 8% due to mobile source and 7% due to point sources when these source's emissions are applied single. ORAM system has the flexibility to easily incorporate other health-endpoints such as mortality and minor restrictive activity days (MRAD), and also other pollutants such as particulate matter and other gases. Finally, because the equations in ORAM are for short-term effects (daily variation), the system developed can be used in a forecasting mode as a complementary tool in the ozone action programs such as Spare the Air or Ozone Action Days. |
