Aerosols directly and indirectly modify cloud properties and consequently have various effects on the climate. They possess significant potential to change circulation fields through changes in the radiation budget. We used earth system model simulations to estimate the effects of anthropogenic aerosols on the climate over East Asia in the future, where the emission of anthropogenic aerosols is expected to decrease owing to measures being taken to control air pollution. Anthropogenic aerosols have negative effects on surface temperature and precipitation and positive effects on cloud cover; these effects of aerosols become slightly weaker with decreasing anthropogenic aerosol emissions. Thus, a reduction in aerosols may weaken their cooling effect. Because of that, measures for the emission control of aerosols may promote global warming and precipitation over East Asia. In this study, the rate of change in temperature and that in precipitation caused by increasing of greenhouse gases is estimated to be 0.35 K/10-year and 0.69%/10-year, respectively, over East Asia. On the other hand, combining aerosol decreasing and the greenhouse gas effect just mentioned provides the increasing rate with 0.46 K/10-year in temperature and 2.6%/10-year in precipitation. The results suggest that decreasing of anthropogenic aerosols contributes to temperature rising and increased precipitation.

　The study evaluated the possibility of using tape from air monitoring station for polycyclic aromatic hydrocarbons (PAHs) data. Thermal desorption/gas chromatography-mass spectrometry (TD/GC-MS) was utilized to analyze 12 PAHs in PM_2.5 samples, collected on the glass fiber filter tape by a continuous PM_2.5 mass concentration monitor operated in Ho Chi Minh City, Vietnam during Vietnamese New Year (VNY) holidays. The analysis of PAHs was performed 4 years after the sample collection. The results showed that the PAH data can be acquired from air monitoring tape, and the estimated total PAHs can be assessed. This is the first study about the change in air quality due to the cultural activities in Vietnam. The PAH concentrations were dependent intensely on traffic patterns, with the decrease of PM_2.5 and PAH concentrations throughout holidays. In addition, wood/coal combustion related to the firework, domestic combustion, and burning incense/candle were important sources during holidays. The value of the IcdP/(IcdP＋BghiP) ratio was 0.72 in VNY, which was similar to that from cooking, candle, and incense burning. The average incremental lifetime cancer risks were 9.5 for adults and 1.8 for children per 100,000 people during sampling time, which were within the acceptable risk of 10^-6–10^-4.

　Carbon nanotubes (CNTs) coated with other materials are expected to be useful in many applications. The performance of coated CNTs is known to depend on the morphology of the coating layers. In this study, the effects of the conditions of a gas-phase method of coating via plasma-enhanced chemical vapor deposition on the surface of CNTs suspended in gas on the morphology of CNTs are investigated. An increase in the concentration of the precursor for the coating material is found to enhance the formation of coating layers consisting of particulate materials. An increase in the pressure of the plasma reaction zone also leads to a thicker particulate coating layer. In contrast, dense and continuous coating layers are obtained when the plasma reaction is given a longer time. The thickness of such layers tends to increase with time. The difference in the morphologies is considered to be due to the frequency of nuclei formation, and the rate and time allowed for the growth of these nuclei. Each of the morphologies observed here is interesting from the viewpoint of various applications; therefore, the findings from this study will provide useful information on techniques for controlling the morphology of coatings.