Evolution of air pollution events determined from Raman lidar
Document ID: 146
Mulik, Karoline R.1
Li, Guangkun1
Chadha, Ginnipal S.1
Philbrick, C. Russell1
Mathur, Savyasachee L.2
1 The Pennsylvania State University, Department of Electrical Engineering, University Park, PA, U.S.A.
2 Science and Engineering Services, Inc., Burtonsville, MD, U.S.A.
Abstract
Analyzing data obtained during atmospheric pollution episodes, which generally result in increases in both ozone and fine particle matter, provides a means of describing the evolution of pollution events and the influence of the local meteorology in changing the particle and chemistry distributions in the lower atmosphere. Vertical profiles of atmospheric constituents were obtained using a multi-wavelength Raman lidar to describe pollution events in the lower atmosphere. The signal profiles from Raman scatter wavelengths at 607, 530, and 285 nm, and the lidar backscatter at 532 nm were used to measure optical extinction, while at the same time Raman lidar measurements were used to obtain profiles of water vapor, temperature, and ozone. Correlation between backscatter and extinction measurements provides a means of describing variations in atmospheric aerosol and particulate matter in the lower atmosphere. It is important to obtain improved ways of measuring the distribution of airborne particulate matter, which has been shown to have a strong correlation with health and respiratory problems. Investigations of the relationships of profiles of optical extinction with profiles of water vapor and ozone are useful in understanding the evolution of pollution events. Water vapor time sequences provides a most useful description of the boundary layer dynamics. Examination of atmospheric pollution episodes shows strong correlation between ozone and aerosol concentrations within the planetary boundary layer. The correlation could be due to common meteorological conditions, such as stagnant air mass, or to common formation processes from chemical and photochemical production paths. Several pollution events have been used to study variations in extinction, backscatter, water vapor, and ozone measurements from the NARSTO-NEOPS investigations in Philadelphia during summer 1998 and 1999. These measurements demonstrate a strong correlation between ozone and aerosol during air pollution events.