• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2002.11a
• /
• pp.137-138
• /
• 2002

입자상 물질은 자연적 또는 인위적인 오염원에 의해 직접 대기로 배출되거나 가스상 물질의 전환 과정을 통해 생성된다. 서울을 비롯한 우리나라 시정(visibility)은 맡은 부분이 가스상 물질의 전환을 통해 생성된 미세 입자에 영향을 받고 있기 때문에 미세 입자의 생성(formation)과 성장(growth) 변화를 연구하는 것은 시정(visibility)의 원인을 밝히는 중요한 과정이라고 할 수 있다. (중략)

• Journal of Korean Society for Atmospheric Environment
• /
• v.29 no.5
• /
• pp.656-667
• /
• 2013

The non-exhaust coarse, fine, and ultrafine particles were characterized by on-road driving measurements using a mobile sampling system. The on-road driving measurements under constant speed driving revealed that mass concentrations of roadway particles (RWPs) were distributed mainly in a size range of 2~3 ${\mu}m$ and slightly increased with increasing vehicle speed. Under braking conditions, the mode diameters of the particles were generally similar with those obtained under constant speed conditions. However, the PM concentrations emitted during braking condition were significantly higher than those produced under normal driving conditions. Higher number concentrations of ultrafine particles smaller than 70 nm were observed during braking conditions, and the number concentration of particles sampled 90 mm above the pavement was 6 times higher than that obtained 40 mm above the pavement. Under cornering conditions, the number concentrations of RWPs sampled 40 mm above the pavement surface were higher than those sampled 90 mm above the pavement. This might be explained that a nucleation burst of a lot of vapor evaporated from the interaction between the tire and the road pavement under braking conditions continuously occurred by cooling during the transport to the sampling height 90 mm, while, for the case of cornering situations, the ultrafine particle formation was completed before the transport to the sampling height of 40 mm.

• Asian Journal of Atmospheric Environment
• /
• v.5 no.1
• /
• pp.21-28
• /
• 2011

Occupational nanomaterial exposure is an important issue in the manufacture of such products. People are also exposed to various nanoparticles in their living environments. In this study, we investigated nanoparticle formation during the reaction of ozone and volatile organic compounds (VOCs) emitted from a commercial air freshener, one of many widely used consumer products, in a $1-m^3$ reaction chamber. The air freshener contained various VOCs, particularly terpenes. A petri dish containing 0.5 mL of the air freshener specimen was placed in the bottom of the chamber, and ozone was continuously injected into the center of the chamber at a flow rate of 4 L/min with an ozone concentration of either 50, 100 or 200 ppb. Each test was conducted over a period of about 4 h. The higher ozone concentrations produced larger secondary nanoparticles at a faster rate. The amount of ozone reacted was highly correlated with the amount of aerosol formation. Ratios of reacted ozone concentration and of formed particle mass concentration for the three injected ozone concentrations of 50, 100 and 200 ppb were similar to one other; 4.6 : 1.9 : 1.0 and 4.7 : 2.2 : 1.0 for ozone and aerosol mass, respectively.