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The publicʼs concern on ambient PM10 has increased sharply since 2013. To check whether the concern is related the PM10 concentration, the trends of (1) the annual mean PM10 concentration, (2) the frequency by the PM10 concentration interval, and (3) the high concentration occurrence duration time are studied. It is found that all three indicators have decreased between 2001 and 2017. For example, the annual mean PM10 concentration decreased from 71 μg/m³ in 2001 to 44 μg/m³ in 2017 in Seoul. Generally, the frequency of the PM10 concentration over 50 μg/m³ has decreased while that less than 20 μg/m³ has changed little. Thus, the frequency between 20 and 50 μg/m³ has increased. However, different trends in the PM10 concentration, frequency by concentration level and frequency over 50 μg/m³ for duration are observed among the administrative districts. To reduce the annual average concentration of PM10, there should be more measures to reduce the frequency of PM10 concentration between 20 and 50 μg/m³ as well as over 50 μg/m³ for increasing the frequency of low PM10 below 20 μg/m³.

A consumption based study on the carbon dioxide(CO 2 ) emission change due to the changes in the bovine meat consumption behavior in Korea was carried out. It was found that if the consumption of bovine meat be reduced by half, the reduction amount of CO 2 emissions be over 0.8 MtCO 2 e in all senarios in 2023. This amount is equivalent to over 50% of the greenhouse gases(GHGs) emission reduction target in agriculture and forestry, and fishery, a significant reduction. It was also found that the CO 2 emission reduction amount in consumption-based approach was the largest when the consumption of the imported bovine meat be reduced, though the difference was not that large. Key words : Meat consumption, Consumption-based approach, Carbon dioxide emission, National GHGs reduction target *Corresponding author. Tel : +82-(0)2-3277-2832, E-mail : yong@ewha.ac.kr Journal of Korean Society for Atmospheric EnvironmentVol. 31, No. 4, August 2015, pp.356-367DOI: http://dx.doi.org/10.5572/KOSAE.2015.31.4.356p-ISSN 1598-7132, e-ISSN 2383-5346

The literature data of the mass concentrations of TSP, , and , and chemical composition of (sulfate, nitrate, ammonium, OC, and EC) from 1985 and 2013 at Seoul were collected and the temporal trends were discussed in relation with the policy directions. Generally, the mass concentrations of TSP, , and at Seoul have showed decreasing trends. However, it is not clear what might be the major reason(s) for the trends. The concentrations of ionic component in showed different trends, sulfate being reduced during the 1990s but no trend during the 2000s. The concentrations of nitrate and ammonium were increasing during the 2000s. The concentrations of OC show no apparent trend while that of EC decreased. Further policy directions are suggested based on the temporal trends of the chemical composition in .

The trends of the criteria air pollutants` concentrations over Seoul are reviewed, relative contributions of major sources are discussd, and directions for future air quality management are suggested. It was shown that the yearly average concentrations of the criteria air pollutants except nitrogen dioxide and ozone have decreased significantly over the last three decades. Though the concentration of nitrogen dioxide has not decreased, the concentration of has decreased significantly. The major reason for the reduction of the criteria air pollutants has been strict government regulations such as establishment of strict emission standards and switch to cleaner fuels. However, it is not clear the major reason (s) for the reduction of the concentration. It is suggested that to further reduce the concentrations of secondary air pollutants such as ozone and , understanding the major chemical pathways for them is essential. In addition, influence from outside Seoul should be quantified and effectively controlled.

Various antimicrobial technologies have been developed to inactivate bioaerosols in indoor environments. In this study, air filter media were treated with a natural antibacterial agent of Sophora flavescens in order to inactivate the bacteria collected on the air filter. Three treatment methods were applied to manufacture the test antibacterial air filter media: electrospray, nebulization and dip-coating methods. In case of electrospray and nebulization processes, the size distribution of aerosolized natural antibacterial agent was measured using a scanning mobility particle sizer. Staphylococcus epidermidis bacteria were aerosolized to test inactivation of the filter media treated with a natural antibacterial agent. The pressure drop and the antibacterial efficiency of the filter media increased with increasing the mass loading of natural antibacterial agent in each treatment method. The antibacterial efficiency per loaded antibacterial agent mass by the electrospray method was the highest and the filter treated by the dip-coating method was the lowest among three treatment methods.

The TSP aerosols were collected at Gosan site of Jeju Island between 2003 and 2007, and their aerosol components were analyzed to examine the variations of chemical compositions with the corresponding pathways of inflowing air parcels. According to the comparison of seasonal aerosol compositions, the soil-originated components showed remarkably high concentrations during spring season. On the other hand, the concentrations of anthropogenic components were somewhat high in spring and summer seasons, but low in fall season. Based on the comparison of TSP compositions in relation to the pathways of inflowing air mass, the concentrations of anthropogenic components (nss-, S, ), soil-originated components (nss-, Al, Fe, Ca), and the heavy metals (e,g., Mn, Zn, Cr, Pb, Cu, Cd, etc.) have relatively increased with the air mass moving from China continent into Jeju area. Meanwhile, the marine-originated components showed an increasing trend with the air mass coming from North Pacific Ocean. In the seasonal and sectional comparison, the nss-, , nss-, and Al showed comparatively high concentrations when the air mass moved from China continent during all seasons. Especially, the , nss-, and Al concentrations were somewhat high when the air mass moved from Korean Peninsula during summer season. It was also recognized that the Na+ concentration were high, when the air mass moved from Pacific Ocean through all seasons.

Data on the energy usage including biomass, emissions of air pollutants (, , CO), and the air quality in North Korea are analyzed. The energy usage in North Korea has decreased in the 1990s and thus, the emission amount of air pollutants. Coal and biomass constitute a major fraction of energy sources since the 1990s. It is identified that the emission amount of air pollutants per unit energy consumption in North Korea is much higher than South Korea for the period data are available (since 1990) implying that the air pollutant emission management system in North Korea is inadequate. In particular, the amount of biomass burning for household cooking and heating is significant with the huge emissions of air pollutants such as CO and organic species both in the gas and aerosol phase. Furthermore, it is found that the existing energy usage and air pollutant emission data are not consistent in biomass burning related data.

Characteristics and advantages of the thermal desorption-comprehensive two dimensional gas chromatography-time of flight mass spectrometry (TD-GCxGC-TOFMS) were discussed and the organic compound`s analysis result was shown for the ambient sample collected in Seoul, Korea. Over 10,000 individual organic compounds were separated from about of aerosols in a single procedure with no sample pre-treatment. Among them, around 300 compounds were identified and classified based on the mass fragmentation patterns and GCxGC retention times. Several aliphatic compounds groups such as alkanes, alkenes, cycloalkanes, alkanoic acids, and alkan-2-ones were identified as well as 72 PAH compounds including alkyl substituted compounds and 8 hopanes. In Seoul aerosol, numerous oxidized aromatic compounds including major components of secondary organic aerosols were observed. The inventory of organic compounds in of Seoul, Korea suggested that organic aerosol were constituted by the compounds of primary source emission as well as the formation of secondary organic aerosols.

The concentrations of PAHs in fine particles were determined at two sites, which were Jongno, one of the urban core sites of Seoul, and Yongin, a downwind site of Seoul. The average concentration of PAHs in was with the range of at Jongno site of Seoul from August 2006 to August 2007, and with the range of at Yongin site from September to November of 2006. In the results of monthly comparison, the concentration of PAHs in August was the lowest level of , but the highest level of in January. The seasonal comparison showed the concentration in winter was higher by the factor of 11.9 than in summer. The concentrations of PAHs during a warm period (NovemberMarch) increased as 5.1 times higher than those during a cold period (AprilOctober). The concentrations of PAHs were assumed to be largely attributed to the consumption of fossil fuels, temperature, mixing height, and photochemical reactions in Seoul metropolitan area.

Five intensive measurements of particulate PAHs were made at a roadside in Seoul from May 2005 to June 2006. The average concentration of particulate PAHs was . The high concentrations of particulate fluoranthene and pyrene were observed in November 2005 due to the influence of the lower ambient temperature. Compared to the previous results at tunnel and ambient sites in Seoul, larger fraction of the high molecular PAH compounds which consist with five or six benzene rings, was observed at a roadside. This might indicate high influence of vehicle emission at a roadside. The distribution of diagnostic ratios for specific PAH compounds indicated that the influence of vehicular emission, especially diesel vehicular emission seems to be high at a roadside.

To reduce the vehicular emissions of air pollutants, various traffic control programs (TCPs) have been used. In 2002, two TCPs have been implemented in Seoul and Busan, respectively. In this study, based on the study results on the effectiveness of the TCP in Seoul (Kim et al., 2005) and Busan (Lee et al., 2006), emission reduction by the TCP in Seoul was estimated and their contribution to the ambient air pollutants` concentrations was discussed. During the TCP period in 2002 at Seoul, emissions of air pollutants were reduced by 35% for CO and , 80% for HC, 23% for , and 24% for . Vehicular emission reduction affected the ambient concentrations significantly for . However, for , vehicular emission reduction did not affect the ambient concentration significantly. For , vehicular emission reduction did not affect the ambient concentration significantly if considering fugitive emissions.

Feasibility test for a biofilter was performed to treat VOCs. The applied loading rate to the biofilter was calculated between 60 to 3,700 kg COD/㎥. Trimethyl-pentene and trimethyl-hexene were the two most dominant compounds and they occupy about 85 percent. During the acclimation period, it is desirable for a biofilter to receive relatively lower VOCs concentration and flow rate, until it can adjust to new substrate and operational environment. Temperature at various points inside the biofilter reactor was observed with more than 23 temperature sensors. With steam heating, temperatures of the top sections of the media were greater than those of bottom sections. Without steam heating, intermediate stages generally had higher temperature measurement than those of bottom and top stages. Because the pH values for different biofilter materials vary significantly, measurement of the pH for the mixture of different combinations of biofilter materials is necessary. Based on the types and brands of media, the measured pH ranged from 5.38 to 9.10. The range of measured pH of different mixtures with perlite, compost, saw dust, peat moss, limestone, vermiculite was 7.05 to 8.62.