小型PM採樣器之研發與評估

近幾年來因為室內空氣品質管理法之施行，監測有逐漸家電化的趨勢，而採樣器也勢必須要縮小化，在家中監測時才能不影響到居家生活。另外，PM1及PM2.5的氣膠相（aerosol phase）偵測工具，若要連接氣相（gas phase）吸附採樣裝置，其採樣機具較大，如果想要將其放置於居家環境中連續採樣，不僅較麻煩，也佔據空間。本研究研發新型及體積小之PM1及PM2.5採樣器，並測試評估其分徑效率是否符合US-EPA PM1及PM2.5之分徑標準。研究結合慣性衝擊器及旋風分離器之設計，體積小且輕便。採樣進口設計為可以旋轉，新式採樣器以流率16.7 L/min抽取空氣進入進氣口，並利用慣性衝擊及旋風分離方式分離微粒。而採樣時需用矽油披覆（coating）以避免微粒彈跳。本研究結果顯示，在氣膠暴露腔中以相同16.7 L/min流率，挑戰氣膠為玉米油及酒石酸鉀鈉（potassium sodium tartrate tetrahydrate, PST），並披覆低揮發性矽油的實驗中，以氣動粒徑分析儀（Aerodynamic Particle Sizer, APS）偵測採樣器上下游之微粒濃度及微粒粒徑分布，新研發採樣器之50%截取粒徑分別為1 µm和2.5 µm，接近US EPA PM1及PM2.5標準分徑曲線，並能承受在重量濃度8 mg/m3之兩小時負載採樣，而於實際大氣採樣中與TISCH的實際採樣結果，重量濃度誤差範圍在±2%以內。本研究之新式採樣器於未來可發展成家電產品，使懸浮微粒於居家可隨時監測。

Ambient aerosol sampling is used to evaluate the health hazards associated with particles deposited in the human breathing system. As the enforcement of the PM2.5 standard in recent year in Taiwan, the monitor tends to become home appliance and home-based. The sampling device for particulate matter （PM） must be smaller so as not to affect the home living while monitoring at home. Currently the aerosol sampling device for PM2.5 is too large if connecting with a vapor absorption sampling device. It is troublesome and spacious for continue sampling at home. Impactors, which are extensively employed as aerosol samplers, have low collection efficiency because of particle bounce. The new invented PM1 and PM2.5 samplers combine the theory of inertia impactor and cyclone, and particles that bounce from the impaction surface was imported into the centrifugal vortex to achieve the separation efficiency. The new PM1 and PM2.5 samplers were small and light. In the study, the impaction plate of the new sampler was coated with silicone oil and had a spin cap to prevent particle bounce and re-entrainment. An ultrasonic atomizing nozzle was employed to generate corn oil and soluble potassium sodium tartrate tetrahydrate （PST） challenge aerosols and introduced into aerosol exposure chamber. An Aerodynamic Particle Sizer （APS） was utilized to measure the number concentrations and the size distributions upstream and downstream of the new PM1 and PM2.5 samplers. The experimental results revealed that the new PM1 and PM2.5 samplers coated with silicone oil could minimize PST particle bounce during the two-hour loading sampling （mass concentration was around 8 mg/m3）. In field study, the new PM2.5 sampler only had ±2% error with reference to TISCH ambient PM2.5 sampler. Moreover, the new PM1 and PM2.5 samplers yielded consistent results and could nearly meet the US-EPA PM1 and PM2.5 criteria. The results are useful for designing bounce-free impactor during heavy loading sampling and can be used as the home appliance.