The study of surface ozone concentration and meteorological parameters in Tao-Yuan area

[[abstract]]The air pollution events due to high industrialization become one of the most important environmental issues in Taiwan. In particular, ozone concentration will not only cause human respiratory disease, but also damage plants and buildings. Ozone is a secondary pollutant that is generated by its precursors such as NOX and NMHC through complex photo-chemical reactions. The surface ozone data and meteorological data collected by EPA and CWB during January 1995– December 2004 are analyzed. The hourly data are executed by BASIC computer program to characterize temporal and spatial variation of ozone concentration in Tao-Yuan. On seasonal change, higher ozone concentration usually appears in spring and autumn, and the lower concentration frequently occurs in summer when atmospheric condition is good for dispersion. As to daily variation, in summer time, the strong solar insolation may cause higher ozone concentration at noon. While in winter time, high ozone concentration may occur after sunset and before sunrise duo to surface inversion. In addition, 14 episodes with higher ozone concentration are selected as cases for detailed discussion. In all, some synoptic patterns was important to the occurrence of ozone episodes. Statistics show that the weather condition of high temperature, low cloudiness, and weak wind are considered favorable for the production and accumulation of ozone. Other factors that may affect the atmospheric dispersion, such as mixing height, ventilation index, and precursors emission are suggested for further exploration. The spatial distribution of ozone in Tao-Yuan is also influenced by local land-sea breeze circulation. It is believed that inland pollutant was carried out seaward by land breeze, and changed into ozone through solar insolation. When the sea breeze on sets, the high concentration of ozone may occurred in coastal areas, such as Guan-yin and Da-yuan.