The aerosol nanoparticles are suspected to be exposed to workers in nanomaterial manufacturing facilities. However, the exposure assessment method has not been established. One of important issues is to characterize background level of nanoparticles in workplaces. In this study, intensive aerosol measurements were made at a $TiO_2$ manufacturing laboratory for five consecutive days in May of 2010. The $TiO_2$ nanoparticles were manufactured by the thermal-condensation process in a heated tube furnace. The particle number size distribution was measured using a scanning mobility particle sizer every 5 min, in order to detect particles ranging from 14.5 to 664 nm in diameter. Total particle number concentration shows a severe diurnal variation irrespective of manufacturing process, which was governed by nanoparticles smaller than 50 nm in diameter. During the background monitoring periods, significant peak concentrations were observed between 2 p.m. and 3 p.m. due to the infiltration of secondary aerosol particles formed by photochemical smog. Although significant increase in nanoparticle concentration was also observed during the manufacturing process twice among three times, these particle peak concentrations were lower than those observed during the background measurement. It is suggested that the investigation of background particle contamination is needed prior to conducting main exposure assessment in nanomaterial manufacturing workplaces or laboratories.

Previous designs of conventional aerodynamic lenses have a limitation of narrow range of focusable particle size, e.g. 30 to 300nm or 3 to 30nm. To enlarge the focusable size range to 30-3000nm, it is necessary to avoid a significant loss of particles larger than 300nm inside the lenses. From numerical simulations on size-resolved particle trajectories, we confirmed that the traveling losses of such large particles could be avoided only when the radial position of particles approaching the orifice lens was near the lens axis. Hence, we designed the lens system consisting of a converging-diverging nozzle and 7 orifices to fulfill the requirement. In particular, the orifices were aligned in a way that their diameters were descending and ascending to the downstream. As a result, 30-2800nm particles can be focused to the particle beam of 0.2mm or less in radius with above 85% transmission efficiency. Even $10{\mu}m$ particles can be focused with 74% of transmission efficiency.

우리나라의 대표적인 배경지역 측정소인 안면도의 지구배경관측소에서 20010년에 채취한 미세먼지(PM10) 시료에 대해 n-alkane과 수용성 유기성분(WSOC) 농도를 분석하였다. 우리나라의 또 다른 배경지역인 고산에 비해 봄철의 수용성 유기성분의 농도는 세배 정도 높았다. 안면관측소의 수용성 유기성분의 농도는 서울이나 아시아 다른 도시지역의 농도와 비슷한 수준이었다. 그러나 아시아 도시는 겨울에 농도가 높았으나, 안면관측소는 가을에 높아 배출원, 또는 생성원이 다른 것으로 보인다. 한편 n-alkane 성분의 농도는 안면관측소가 고산보다 약간 낮았고, 서울 등의 아시아 도시의 1/3-1/2 수준으로 낮았다. 그러나 고산은 자연적인 기원의 n-alkane 농도가 높은 반면에 안면관측소는 인위적인 n-alkane이 대부분이어서 대조를 보이고 있다. 따라서 안면관측소는 우리나라의 대표적인 배경지역임에도 불구하고 수용성 유기성분과 n-alkanes 농도측면에서는 배경지역과 도시지역의 특성을 갖고 있어, 인위적인 영향을 많이 받고 있는 것으로 보인다. 보다 상세한 배출원과 생성원 분석은 무기이온농도와 다른 유기성분 분석을 추가하여 이루어질 예정이다.

It is very important to measure atmospheric particles and evaluate the characteristics of them since aerosol can influence atmospheric environment, climate, and health. Satellite, aircraft, radio sonde are usually used to measure the vertical distribution of particle properties, temperature, humidity, and pressure. Although the method of using an aircraft is favorable to collect the horizontal distribution of the particles, but unadaptable to measure the vertical distribution of the particles. However, all-in-one balloon particle sampler system can collect particles depending on each altitude controling the balloon by winch. In this research, we performed the air sampling on the TEM grids using house made light weight impactor at the altitude of 300m and 900m. The collected particles were analyzed using TEM/EDS.