The Environmental Protection Administration (EPA) yesterday said 30 air quality monitoring stations to measure concentrations of particulate matter of 2.5 micrometers or less, known as PM2.5, are scheduled to begin operating in August.
In April, the EPA approved new regulations that set the level of PM2.5 particles that is considered healthy to a maximum 35 microcgrams per cubic meter daily mean concentration and a maximum 15 microcgrams per cubic meter annual mean concentration.
Environmental Analysis Laboratory Division Chief Wu Yueh-chuen (巫月春) yesterday said that in order to understand whether PM2.5 conditions in different parts of the nation have exceeded the limits, the EPA plans to install sampling and testing equipment at 30 of the 76 monitoring stations nationwide.
The testing equipment is set up in clean rooms (rooms in which the concentration level of airborne particles is controlled to fewer than 35,200 particles per cubic meter) — like the high standard of clean rooms in wafer fabrication plants — to preserve the purity of the samples, Director-General Roam Guo-dong (阮國棟) said.
Wu said that in contrast to the 24-hour automatic sequential ambient air particulate samplers currently in the stations, the 30 stations chosen for PM2.5 will be manually operated about once every three days, to adjust the humidity and temperature to maintain constant, uniform levels.
“Differences in humidity can affect the concentration levels of PM2.5,” Wu said, adding that, for example, one PM2.5 substance becomes a liquid in high humidity.
The manually adjusted data are important for comparing the concentration levels of different areas and of different years, without being skewed by variations in humidity or temperature, he added.