• Asian Journal of Atmospheric Environment
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• v.7 no.4
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• pp.177-190
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• 2013

Air pollution trends in Japan between 1970 and 2012 were analyzed, and the impact of air pollution countermeasures was evaluated. Concentrations of CO decreased from 1970 to 2012, and in 2012, the Japanese environmental quality standard (EQS) for CO was satisfied. Concentrations of $SO_2$ dropped markedly in the 1970s, owing to use of desulfurization technologies and low-sulfur heavy oil. Major reductions in the sulfur content of diesel fuel in the 1990s resulted in further decreases of $SO_2$ levels. In 2012, the EQS for $SO_2$ was satisfied at most air quality monitoring stations. Concentrations of $NO_2$ decreased from 1970 to 1985, but increased from 1985 to 1995. After 1995, $NO_2$ concentrations decreased, especially after 2006. In 2012, the EQS for $NO_2$ was satisfied at most air quality monitoring stations, except those alongside roads. The annual mean for the daily maximum concentrations of photochemical oxidants (OX) increased from 1980 to 2010, but after 2006, the $98^{th}$ percentile values of the OX concentrations decreased. In 2012, the EQS for OX was not satisfied at most air quality monitoring stations. Non-methane hydrocarbon (NMHC) concentrations generally decreased from 1976 to 2012. In 2011, NMHC concentrations near roads and in the general environment were nearly the same. The concentration of suspended particulate matter (SPM) generally decreased. In 2011, the EQS for SPM was satisfied at 69.2% of ambient air monitoring stations, and 72.9% of roadside air-monitoring stations. Impacts from mineral dust from continental Asia were especially pronounced in the western part of Japan in spring, and year-round variation was large. The concentration of $PM_{2.5}$ generally decreased, but the EQS for $PM_{2.5}$ is still not satisfied. The air pollution trends were closely synchronized with promulgation of regulations designed to limit pollutant emissions. Trans-boundary OX and $PM_{2.5}$ has become a big issue which contains global warming chemical species such as ozone and black carbon (so called SLCP: Short Lived Climate Pollutants). Cobeneficial reduction approach for these pollutants will be important to improve both in regional and global atmospheric environmental conditions.

• Journal of Integrative Natural Science
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• v.2 no.2
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• pp.131-167
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• 2009

Global warming is regarded as one of the most critical issues that should be taken care of by the entire global community as it threatens the survival of mankind. South Korea, in particular, undergoes faster warming than the average rate of global warming. South Korea has revealed various warming rates and trends being surrounded by sea on three sides and having complex terrains dominated by mountains. The rates vary according to regions and their urbanization and industrialization. Differences also derive from seasons and weather elements. Changes to the highest, mean, and lowest temperature are also different according to the characteristics of regions and observatories, which is more apparent where the force of artificial weather applies. In an urban area, temperature gaps tend to decrease as the lowest temperature rises more than the highest temperature. Meanwhile, temperature gaps grow further in a coastal or country region where the force of artificial weather is small and the force of natural weather prevails. In this study, the investigator analyzed the changes to the weather elements of 11 observation spots that had gone through no changes in terms of observation environment since 1961, were consecutively observed, and had the quality of their observation data monitored on an ongoing basis. Using the results, I tried to identify natural and artificial causes affecting certain spots. Located on the east coast of the Asian Continent, South Korea sees weather changing very dynamically. Having huge influences on our weather, China has achieved very rapid industrialization for the last 30 years and produced more and more greenhouse gases and air pollution due to large-size development projects. All those phenomena affect our weather system in significant ways. Global warming continues due to various reasons with regional change differences. Thus the analysis results of the study will hopefully serve as basic data of weather statistics with which to set up countermeasures against climate changes.