Vertical Profile and Spatial Distribution of Ozone and Its Precursors at the Inland and Offshore of an Industrial City

Received: January 22, 2012
Revised: March 22, 2012
Accepted: March 22, 2012
Download Citation: RIS|BibTeX|https://doi.org/10.4209/aaqr.2012.01.0018  

Cite this article:
Tsai, H.H., Liu, Y.F., Yuan, C.S., Chen, W.H., Lin, Y.C., Hung, C.H., Lin, C., Jen, Y.H., Ie, I.R. and Yang, H.Y. (2012). Vertical Profile and Spatial Distribution of Ozone and Its Precursors at the Inland and Offshore of an Industrial City. Aerosol Air Qual. Res. 12: 911-922. https://doi.org/10.4209/aaqr.2012.01.0018

ABSTRACT

This study investigated the ozone formation mechanism and air mass trajectory via simultaneous air quality sampling around the coastal region of urban Kaohsiung. Vertical concentration profiles of O₃ and its precursors (NO_x and VOCs) were sampled and measured at inland and offshore sites during eight intensive sampling periods. The intensive sampling periods were divided into three categories based on meteorological condition: the sea-land breeze period, the northeastern monsoon period, and the mixed period. Vertical profile results showed that the stratification of O₃ was commonly observed at 40 out of 64 sampling sites accounting for 62.5% of the total O₃ measurement. The results obtained from VOCs measurement indicated that the major species of VOCs was acetone, which accounted for 16.25–64.05% of total TVOCs-C₂ in the offshore region, while the major species of VOCs in the inland region was toluene, which accounted for 6.41–43.77 % of total TVOCs-C₂. Backward trajectories showed that air pollutants emitted from land sources could transport to the offshore region, resulting in a high concentration of oversea NO_x and VOCs. Major species of VOCs with high O₃ formation potential were found to be aromatics in the low atmosphere around the coastal region of metro Kaohsiung.

Keywords: Ozone and its precursors; Vertical profile; Stratification phenomenon; Meteorological condition