Examination of the influence of a frontal passage on air pollution episodes
Document ID: 167
Unni, Sameer1
Philbrick, C. Russell1
Ryan, William F.1
Clark, Richard D.2
1 The Pennsylvania State University, University Park, PA, U.S.A.
2 Millersville University of Pennsylvania, Millersville, PA, U.S.A.
Abstract
The effects of meteorological fronts on air quality have been of great interest to researchers. Knowledge of these effects assumes significant importance in the wake of studies correlating increased ozone and particulate matter with adverse health effects. Air quality and health experts believe that the health hazard is in the small particle component, PM2.5, which is inhaled by humans and deposited in the bronchioles and alveolar sacs in the respiratory system, leading to adverse health effects. Local air pollutants, such as nitrogen oxides (NOx) and hydrocarbons, may control the complex ozone response. However, the regionally transported ozone and precursors provide most ground-level ozone in many of the largest episodes. Ozone is formed indirectly by the action of sunlight on volatile organic compounds and nitrogen oxides. In addition, about 10-15% of ground-level ozone is transported down from the stratosphere.
Frontal activity can be closely studied by using water vapor as a tracer of variations in the planetary boundary layer (PBL). Variations in the PBL thickness control the dilution volume for the chemical species injected into the atmosphere. Additionally, wind gusts (ahead of a front) and gravity waves (evident in the water vapor concentration) provide interesting evidence of the dynamical processes that rapidly change characteristics of the local air masses as the front moves through the region. The dynamics causes mixing of ozone, which results in ozone depletion due to oxidation loss from increased interaction with the surface.
| Citation: | "Examination of the influence of a frontal passage on air pollution episodes", Unni, S., C. R. Philbrick, W. F. Ryan, R. D. Clark, Bulletin of the American Meteorological Society, American Meteorological Society, Section: 6.8, 2003, pp. 1 - 4 |