| dc.description.abstract | In this study, characteristics of gaseous pollutants at a high altitude (~3 km) and surface level in Taiwan were investigated by the observatories at Lu-Lin baseline station and PAMS stations, respectively. Elevated concentration and CO and O3 were measured in spring at Lu-Lin due to biomass burning in Southeast Asia. During the same period, a relatively higher values of ethane/n-butane compared to those in summer was also observed at Shaung-Yuan PAMS station, which indicates the aged continental air masses carried by the monsoon impacting northern Taiwan. In springtime, the abrupt changes from domestic to long-range transport (LRT) conditions for the 4 LRT events identified in Taipei metropolitan area can be sensitively reflected on the variation of the ethane/n-butane ratios, which is consistent with the changes of O3 and NOx concentrations. The north-easterlies in spring can also affect the ages of air masses in central Taiwan, resulting in relatively higher ethane/n-butane and O3 levels than those in summer as observed by the Chu-Shang PAMS station. However, in this study, ethylbenzene/m,p-xylene was found more sensitive than ethane/n-butane in terms of revealing the phenomenon of land-sea breeze. Meanwhile, the diurnal variations of CO at Lu-Lin were found to be driven by mountain-valley breezes. The coupling of the two atmospheric movements is yet to be investigated.
The measurements of the mostly anthropogenic halocarbons showed steady-state trends throughout the period from the end of 2007 to 2009, which was the result of the global phase-out of these substances. Meanwhile, greenhouse gases were found to have significant growth during the same period.
Situating on the rim of west Pacific facing east China, Taiwan can serve as an ideal location for monitoring the change of air pollutants to assess the level of impact. Our knowledge of the gaseous air pollutants via these well-operated stations can shed light to the understanding of many aforementioned issues, i.e., LRT of Asian continental outflows or biomass burning emissions from Southeast Asia.
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