| 英文摘要 |
Compared to Taiwan air quality standards, the annual PM10 concentration has been reduced to below 60 μg/m3 within four years. In 2020, the annual average of PM10 was (30.2±8.1) μg/m3, lower thanair quality standard. PM2.5 was (15.1±3.7) μg/m3, still slightly higher than air quality standard (15 μg/m3). It mean strategy should be adopted to reduce pollutant emission, as well as to improve the monitor performance.
U.S. EPA recommends to implement performance evaluation program of PM2.5 moniors and all monitors should be audited in a period of 6 year. The performance evaluation of PM2.5 and PM10 contined monitors are not yet implemented for all monitoring stations in the air quality monitoring network in Taiwan. In this project, our first task focus on set up a collocation comparison mechanism, procedure, and maxnium permissible tolerance for performance evaluation of continued automatic PM10 and PM2.5 monitors, including new purchased monitors implemented by 2019. The task has been completed by the end of June, 2021. Second task is to assist government on replacement of PM2.5 monitors and the work has been done by June of 2019. All new purchased monitors are installed in different stations and take over the mission of air quality monitoring since the end of 2019. During the replacing period of instruments, works have been done with installitation, testing, parameter setting and adjustment, as well as data analysis between new and old monitors.
After all new purchased PM2.5 monitors are all installed in stations, we also do some performance evaluation experiments. As a preliminary results, we have three findings: (1) the zero point filter background tests of monitors need to be adapted based on local environemntal conditions. In Nothern Taiwan, the frequency of testing and adjustment could be once per year. Then, it is recommended to strengthen and increase the frequency in South. Ambient humidity might be the key factor affecting the shift of zero point; (2) the heating of the sampling pipe can avoid the condensation of water in the pipe. The adjustment principle is to control the inner air relative humidity of the pipe between 30 to 35 degrees.
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