Real-time monitoring of hourly atmospheric radon (Rn-222) concentration was performed throughout 2011 at Gosan station, Jeju Island, one of the least polluted regions in Korea, in order to characterize the background levels, and temporal variations on diurnal to seasonal time-scales. The annual mean radon concentration for 2011 was 2527 ± 1356 mBq m ) at around 7 a.m., after which they decreased to their minimum value (2259 mBq m ) at around 3 p.m. Back trajectory analyses indicated that the highest radon events typically exhibited long-term continental fetch over Asia before arriving at Jeju. In contrast, low radon events were generally correlated with air mass fetch over the North Pacific Ocean. Radon concentrations typical of predominantly continental, and predominantly oceanic fetch, differed by a factor of 3.8.
The purpose of this study is to show the geographical distribution and the temporal variation of the emission amount of biogenic volatile organic compounds(BVOCs) emanated from forests at Jeju Island.The total emission amount of BVOCs calculated by using the CORINAIR Methodology is 3612 ton yr -1 at Jeju Island. More than half of BVOCs emissions is come from coniferous forest, and 45 per cent from broad leaved forest. The others is attributed to grassland. Of total emission of BVOCs, isoprene accounts for 28 per cent, monoterpene for 32 per cent, and other VOCs for about 40 percent, respectively. It can be shown that 3000~10000 kg yr -1 of BVOCs is emitted at the zone with dense forest from an altitude of 500 m to the top of Mt. Halla, and less than 1500 kg yr -1 at the zone an altitude of below 500 meters. The monoterpene emission is more than 1500 kg yr -1 due to the existence of a colony of Abies koreana at the place with more than 1500 meters and a community of Pinus thunbergii and Cryptomeria japonica at the elevation of 500~700 m. In the case of isoprene emission, there is 1500~3000 kg yr -1 at the zone of an elevation from 700 m to 1500 m due to dense broad leaved forest and very little of its emission at an elevation of more than 1500 meters because there is hardly broad leaved trees grown. In this study, emission of BVOCs according to the altitude above sea level is estimated under the situation of lack of the data for broad leaved tree. More detailed data and information for the distribution of broad leaved trees are needed in order to calculate more realistic BVOC emission.
The realtime monitoring of radon ( ) at around 3 p.m. From the backward trajectory analysis for a continental fetch of radon, the high concentrations (10%) of radon matched with the air mass moving from the Asia continent to Jeju area. In contrast, the low concentrations (10%) of radon were generally correlated with the air mass of the North Pacific Ocean. In comparison by sectional inflow pathways of air mass, the radon concentrations were relatively high from the north China and the Korean peninsula.
This study was carried out to estimate the BVOCs emissions with the emission factors which reflected the native conditions of forests in Jeju Island. This study made effective use of the previous data for the weather data and the emission rate of each organic volatile component measured at 10 species of conifers and broad leaved trees. The CORINAIR method and the grid system of 1km×1km for whole area of Jeju Island were adopted in calculating the BVOCs emission emitted from forest. The vegetation information for Jeju Island was referred to GIS and a government report. By the results of BVOCs emission for Jeju Island, the 85% of monoterpene emission was emitted from conifers and the others was from broad leaved trees. Most of monoterpene emission was attributed to Pinus thunbergii and Cryptomeria japonica. The broad leaved trees greatly contributed to the isoprene emission and Quercus serrata played a dominant role in emission of isoprene. The total amount of BVOCs emission was estimated as 3612 ton yr -1 in Jeju Island. The 51.1% of total emission was contributed to conifers, the 44.9% to broad leaved trees, and the 4.0% to grassland. Of total emission of BVOCs, monoterpene accounted for 32.3%, isoprene for 28.0%, and OVOCs for 39.7%. The BVOCs emission estimated by this study was less than that estimated by other previous study. This means that it is important to survey the emission rate at native conditions and gather the detailed information for various species of vegetation on target region.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.