• Journal of Environmental Science International
• /
• v.14 no.2
• /
• pp.231-240
• /
• 2005

The number of cases exceeding environmental standards of atmospheric ozone in the major cities in Korea has steadily increased during the past decades. In order to understand and analyze the atmospheric reactions in the atmosphere, especially the secondary photochemical reactions, smog chambers studies have been performed very actively by many research groups worldwide. However, these studies have focused on the mechanism of photochemical reactions in high concentration conditions, not at the ambient levels. Therefore, in-depth studies in these conditions are essentially needed to realize exact mechanism in the atmosphere near the earth surface, especially at Korean atmospheric conditions. In this experiment, the mechanism of photochemical smog was examined through a comparative experiment of smog chambers under sun light and black light conditions. The results of our study indicated that concentrations of ozone, aldehyde, and PAN increased as the radiation of light source increases. Photochemical reaction patterns can be considered quite similar for both black light and sun light experiments. Based on our experiments using toluene as a reactant which is present at significant high levels in ambient air relative to other VOCs, it was found that toluene could contribute notably to oxidize NO to $NO_2$, this reaction can eventually generate some other photochemical oxidants such as ozone, aldehyde, and PAN. The results of simulation and experiments generally showed a good agreement quite well except for the case of $O_3$. The restriction of oxidization of NO to $NO_2$ seems to cause this difference, which is mainly from the reaction of peroxy radical itself and other reactants in the real gas.

• Journal of Korean Society for Atmospheric Environment
• /
• v.20 no.E1
• /
• pp.35-41
• /
• 2004

Aerosol wall loss is an important factor affecting smog chamber experiments, especially with chambers made of Teflon film. In this work, the aerosol wall loss was investigated in 2.5 and $5.8-m^3$ cubic-shaped Teflon film chambers filled with ambient air. The natural change in the particle size distribution was measured using a scanning mobility particle sizer in a dark environment. The rate of aerosol wall loss was obtained from the deposition theory suggested by Crump and Seinfeld (1981). The measured rates of aero-sol wall loss were In a good agreement with the theoretical and experimental values given by McMurry and Rader (1985), implying that the electrostatic effect enhances particle deposition on the chamber wall. The significance of aerosol wall loss correction was demonstrated with the photochemical reaction experiments using the ambient air.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2002.11a
• /
• pp.135-136
• /
• 2002

최근 들어, 대도시 지역에서 오존(O$_3$)농도가 환경기준을 초과하는 빈도가 증가함에 따라 대기 중 광화학 대기오염현상과 그에 따른 오존 등 2차 광화학 오염물질에 대해 많은 관심이 집중되고 있다. 이러한 복잡한 대기중의 반응을 이해하고 해석하기 위하여 Smog Chamber를 이용한 대기 중 광화학 반응 연구가 진행 중에 있으며, 국내에서도 연구가 이루어지고 있다 Smog Chamber를 통해 대기 중의 광화학 반응의 세부적인 이해와 수학적 모델에 필요한 화학반응들의 변수를 제공하는 등 포괄적이고 종합적인 연구를 수행할 수 있다. (중략)

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2004.05a
• /
• pp.231-232
• /
• 2004

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2004.05a
• /
• pp.233-234
• /
• 2004

• Journal of Korean Society for Atmospheric Environment
• /
• v.32 no.2
• /
• pp.131-157
• /
• 2016

A smog chamber has been an effective tool to study air quality, particularly secondary organic aerosol (SOA), which is typically formed by atmospheric oxidation of volatile organic compounds (VOCs). In controlled environments, smog chamber studies have validated atmospheric oxidation by identifying, quantifying and monitoring products with state-of-art instruments (e.g., aerosol mass spectrometer, scanning mobility particle sizer) and provided chemical insights of SOA formation by elucidating reaction mechanisms. This paper reviews types of smog chambers and the current state of smog chamber studies that have accomplished to find pathways of SOA formation, focusing on gas-particle partitioning of semivolatile products of VOC oxidation, heterogeneous reactions on aerosol surface, and aqueous chemistry in aerosol waters (e.g., cloud/fog droplets and wet aerosols). For future chamber studies, then, this paper discusses potential formation pathways of fine particles that East Asia countries (e.g., Korea and China) currently suffer from due to massive formation that gives rise to fatal health problems.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2004.11a
• /
• pp.137-138
• /
• 2004

• Particle and aerosol research
• /
• v.9 no.3
• /
• pp.149-161
• /
• 2013

Experiments on photochemical reactions of purified air alone in an indoor smog chamber were carried out after flushing Teflon bags with purified air for many hours in order to check the level of contamination on the chamber wall. Ozone concentrations were linearly increased from <4 ppb up to about 8 ppb with irradiation time for four hours. Outgassing of NOx from the chamber wall was found to be less than 1 ppb. New ultrafine particles were formed and grown up to about 70 nm during the photochemical reactions, and then total number and mass concentrations of particles were increased from <10 particles/$cm^3$ up to about 4,000 particles/$cm^3$ and $1.3{\mu}g/m^3$, respectively. The wall conditions of these Teflon bags flushed with purified air might not severly affect the chamber experimental results for photochemical reactions of polluted urban ambient air. The difference of gaseous species between two chambers was 2.4 ppb of ozone at most, indicating that the wall cleaning performance of two chambers was nearly similar.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2003.11a
• /
• pp.239-240
• /
• 2003

스모그 챔버는 대기 중 성분들의 화학 반응 기작을 연구하는데 사용되고 있다. 그러나, 기존 연구에서는 광화학 반응 전구물질의 농도가 실제 대기 농도보다 높고, 청정 공기에 연구 대상 전구물질만을 주입한 단순 혼합물을 이용하였으며, 여러 날에 걸쳐 반응이 진행된 성분들을 이용하지 않았다 (Dodge, 2000). 이와 달리 본 연구팀에서는 실내 스모그 챔버에 실제 대기를 도입하여 광화학 반응 실험을 수행하고 있다 (배귀남 등, 2003). 한 개의 스모그 챔버를 이용하는 경우 외기의 특성상 매 실험마다 초기조건이 달라지기 때문에 단일 인자의 차이에 따른 영향을 파악하기가 쉽지 않았다 (배귀남 등, 2003b). (중략)

• Journal of Korean Society for Atmospheric Environment
• /
• v.20 no.E2
• /
• pp.61-68
• /
• 2004

Aerosol losses in a 100L Tedlar$^{(R)}$ bag were investigated for the aerosols with number median diameter of 0.05 ${\mu}{\textrm}{m}$ and number concentration of 6.4 ${\times}$ 10$^4$ cm$^{-3}$ . Over a 1 hr period, loss of particles in the bag is apparent, and the volume decrease with time is significant. The number concentration, surface area, and volume concentration of the aerosols decreased to 34, 50, and 52% of the initial value in 30 min, respectively. This indicates that deposition to the walls was the main loss process for aerosols in the Tedlar$^{(R)}$ bag. Theoretical calculations showed that coagulations and deposition by diffusion and gravitational sedimentation would not change aerosol characteristics significantly, and the electrical force was the dominant loss process for particles in the Tedlar$^{(R)}$ bag over a 1 hr period.eriod.