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We intensively surveyed the concentrations of chemical species in aerosols and gases using a four-stage filter-pack method at a site in Japan facing the Sea of Japan in winter with 6-h sample intervals. A few chloride species emitted anthropogenically were detected, and the HCl (g) concentration was quite low. The number of chloride species artifacts was also low. The HNO3 (g) concentration was significantly higher when the monitored air mass passed over the Korean Peninsula compared to when it did not pass over the Korean Peninsula. In addition, the HNO3 (g) concentration was significantly higher when the air mass arrived at the monitoring site by passing the route at lower latitude than the latitude of the monitoring site. On the other hand, the SO2 (g) concentration showed no change between various trajectories of the air mass. The $$ {\text{NH}}^{ + }_{4} $$ (p)/non-seasalt- (nss-) $$ {\text{SO}}^{{2 - }}_{4} $$ (p) ratio was intermediate between the compositions of (NH4)2SO4 and NH4HSO4 when the air mass passed over the Korean Peninsula, whereas it was intermediate between NH4HSO4 and H2SO4 when the air mass did not pass over the Korean Peninsula. We detected the transboundary transport of sulfur dioxide with high time-resolution monitoring at two separate monitoring points: the current monitoring site and Oki Island. [ABSTRACT FROM AUTHOR]

abstract We use an inverse model to evaluate the effects of the recent CO2 observations over Asia on estimates of regional CO2 sources and sinks. Global CO2 flux distribution is evaluated using several atmospheric transport models, atmospheric CO2 observations and a “time-independent” inversion procedure adopted in the basic synthesis inversion by the Transcom-3 inverse model intercomparison project. In our analysis we include airborne and tower observations in Siberia, continuous monitoring and airborne observations over Japan, and airborne monitoring on regular flights on Tokyo–Sydney route. The inclusion of the new data reduces the uncertainty of the estimated regional CO2 fluxes for Boreal Asia (Siberia), Temperate Asia and South-East Asia. The largest effect is observed for the emission/sink estimate for the Boreal Asia region, where introducing the observations in Siberia reduces the source uncertainty by almost half. It also produces an uncertainty reduction for Boreal North America. Addition of the Siberian airborne observations leads to projecting extra sinks in Boreal Asia of 0.2 Pg C yr-1 , and a smaller change for Europe. The Tokyo–Sydney observations reduce and constrain the Southeast Asian source. [ABSTRACT FROM AUTHOR]

Abstract: We found a significant geographic gradient (longitudinal and latitudinal) in the sulfate (SO4 2−) concentrations measured at multiple sites over the East Asian Pacific Rim region. Furthermore, the observed gradient was well reproduced by a regional chemical transport model. The observed and modeled SO4 2− concentrations were higher at the sites closer to the Asian continent. The concentrations of SO4 2− from China as calculated by the model also showed the fundamental features of the longitudinal/latitudinal gradient. The proportional contribution of Chinese SO4 2− to the total in Japan throughout the year was above 50–70% in the control case, using data for Chinese sulfur dioxide (SO2) emission from the Regional Emission Inventory in Asia (40–60% in the low Chinese emissions case, using Chinese SO2 emissions data from the State Environmental Protection Administration of China), with a winter maximum of approximately 65–80%, although the actual concentrations of SO4 2− from China were highest in summer. The multiple-site measurements and the model analysis strongly suggest that the SO4 2− concentrations in Japan were influenced by the outflow from the Asian continent, and this influence was greatest in the areas closer to the Asian continent. In contrast, we found no longitudinal/latitudinal gradient in SO2 concentrations; instead SO2 concentrations were significantly correlated with local SO2 emissions. Our results show that large amounts of particulate sulfate are transported over long distances from the East Asian Pacific Rim region, and consequently the SO4 2− concentrations in Japan are controlled by the transboundary outflow from the Asian continent. [Copyright &y& Elsevier]

The atmospheric mixing ratios of perfluorocarbons (PFCs), extremely potent greenhouse gases, have been continuously measured at two Japanese stations (Cape Ochiishi and Hateruma Island) since 2006, to infer their global and regional emissions. The baseline mixing ratios of the measured C(2)-C(4) PFCs [PFC-116 (C(2)F(6)), PFC-218 (C(3)F(8)), and PFC-318 (c-C(4)F(8))] showed slight annual increases of 1%-3%. Enhanced mixing ratios above baseline were occasionally observed at both sites in air masses that had passed over metropolitan regions in East Asia, suggesting high PFC emissions from those regions. We applied transport models to these pollution events and an inversion technique to estimate national emissions. The results suggest that, among the studied regions (China, Japan, North Korea, South Korea, and Taiwan), China was the largest PFC emitter, accounting for more than half of the regional emissions, followed by Japan. The estimated total emissions of each PFC from East Asia were 0.86 Gg yr(-1) for PFC-116, 0.31 Gg yr(-1) for PFC-218, and 0.56 Gg yr(-1) for PFC-318. They contributed greatly to global emissions as derived from the annual increases in the baseline mixing ratios, accounting for more than 75% of global PFC-218 and PFC-318 emissions and for approximately 40% of global PFC-116 emissions.