No abstract

Microplastic pollution is occurring in most ecosystem, yet their presence in high altitude clouds and their influence on cloud formation and climate change are poorly known. Here we analyzed microplastics in cloud water sampled at the summits of Japan mountains at 1300–3776 m altitude by attenuated total reflection imaging and micro-Fourier transform infrared spectroscopy. We observed nine microplastics including polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, polyamide 6, polycarbonate, ethylene–propylene copolymer or polyethylene–polypropylene alloy, polyurethane, and epoxy resin. Microplastic were fragmented, with mean concentrations ranging from 6.7 to 13.9 pieces per liter, and with Feret diameters ranging from 7.1 to 94.6 μm. Microplastics bearing hydrophilic groups such as carbonyl and/or hydroxyl groups were abundant, suggesting that they might have acted as condensation nuclei of cloud ice and water. Overall, our finding suggest that high-altitude microplastics cloud influence cloud formation and, in turn, might modify the climate.

Abstract-Rainwater collected during the period of February to April, 2003, at Kanazawa University, the Japan Sea Coast, was investigated by Ion chromatography for the dissolved ions. The filtered samples were evaluated by various kinds of 1 micro-techniques. The pH, Eh, electrical conductivity (EC), dissolved oxygen (DO), and depleted U (DU) of the rainwater were also measured. The results showed a rare case with low pH and high EC values of rainwater. The

The time variation of chemical composition of individual aerosol particles (including residues of fog droplets) was examined before, during and after fog events, simultaneously with chemical analysis of fog water, near the top of Mt. Norikura in Japan. In this experiment, particle morphology and the presence of S04-, N03 and NH4 in individual particles were determined with an electron microscope using thin-film chemical methods.Acidity (pH) measurements showed that the values of bulk fog water were strongly influenced by fog water content, while those of small size fog droplets (r < 4.0 µm) were not. It was found that change in pH is a function of the droplet size. The pH of the smallest droplets (r < 2.0 µm) sometimes reached as low as 1.6 justYbefore fog dissipation. Particle analysis using a thin film chemical method showed that the nitrate ion was detected in fog droplet residues together with the sulfate ion, even if no nitrate-containing particles were found before fog formation. Direct evidence for sulfate production within fog droplets is also presented. Possible processes which lead to the formation of acidic fog droplets are discussed, based on chemical changes of individual aerosol particles during and outside fog events.

Temporal trends of non-sea salt (nss-) sulfate and nitrate were analyzed from nationwide precipitation chemistry measurements provided by the Ministry of the Environment (MOE) for the 1988-2002 fiscal years (April-March). The concentrations and deposition of nss-sulfate were found to be decreasing, and those of nitrate were stable or slightly increasing at most sites. These deposition trends were discussed from the viewpoint of emissions of SO 2 and NO X during the period of interest. Because monitoring techniques have changed in the number of active sites, samplers, and analytical methods during the operation period, the median of all annual depositions measured in Japan in a specific year was selected as the annual representative. The contribution of specific emission sources was also calculated for 1990 on the basis of the nss-sulfate and nitrate deposition in Japan obtained with a model simulation in which the model Water Air Soil Pollut: Focus (2007) 7:67-75