Atmospheric Environment (v.36, #31)

Releases and transfers from petroleum and chemical manufacturing industries in Korea by H. Park; S. Chah; E. Choi; H. Kim; J. Yi (4851-4861).
Considerable effort and expense have been devoted to the estimation and acquisition of Toxics Release Inventory (TRI) data. To reduce the effort required and the number of reporting mistakes in the calculation of emissions, we developed an estimation program named TRIWIN after standardization of emission estimation techniques. The program was distributed to 6 petroleum and 150 chemical manufacturing companies, and emission data for 62 chemicals were collected and analyzed. From the TRIWIN-based results obtained, it was found that more than 90% of releases from petroleum and chemical manufacturing industries in Korea were emitted to atmosphere in 1999. Volatile organic compounds are major aerial contaminants and are released primarily via fugitive emission sources such as valves, pumps, or flanges. In addition, the effect of the application of point-source management was noticeable on the emission quantities. Consequently, TRIWIN not only helped reporters to implement TRI easily and accurately, but also identified emission sources, major pollutants in facilities, and provided a standard method of assessing the environmental impact of facilities.
Keywords: Toxics Release Inventory; TRIWIN; Petroleum and chemical manufacturing industries; Volatile organic compounds; Fugitive emission sources;

Northern China, covering many deserts, gobi-deserts and arid loess-lands, is one of the world's largest sources of atmospheric dust. In this study, we estimate the dust annual mean emission rates and perform comparative characterization of dust sources in Northern China by combining the geographical, pedological and 30-year (1951–1980) climatological data. Multi-year averaged emission rates of PM50, PM30 and PM10 (i.e., dust particulates smaller than 0.05, 0.03 and 0.01 mm in diameter, respectively) were calculated using the modified US EPA empirical formulas. We demonstrate that the main dust sources in Northern China are the Taklimakan Desert (the annual mean PM10 emission rate, Q 10, is some 0.38 ton/ha yr), the Central gobi-desert (Q 10=0.24 ton/ha yr), and the deserts located on the Alxa Plateau (Q 10=0.05 ton/ha yr). The Loess Plateau appears to be a weak dust source. We identify and characterize three broad types of dust sources in Northern China: Type 1. Deserts in dry-agricultural areas, Type 2. Gobi-deserts and deserts located on the plateaus, and Type 3. Deserts and gobi-deserts located in topographical lows. Types 1–3 sources contribute 1%, 35% and 64%, respectively, to the total annual mean emission of PM10 dust. Although the maximum of dust emission occurs in spring, each source type has a distinct seasonal cycle. The analysis of both the seasonal cycle pattern and spatial distribution of dust emission rates demonstrates that a combination of extreme aridity and strong winds is a key factor governing the dust emission in Northern China.
Keywords: Wind-blown mineral dust; Dust source region; PM10; Emission rate; China;

The atmospheric chemical process was simulated using the Carbon Bond 4 (CB-4) model, the aqueous-phase chemistry in Regional Acid Deposition Model and the thermodynamic equilibrium relation of aerosols with the emission inventories of the Emission Database for Global Atmospheric Research, the database of China and South Korea and the Mesoscale Model version 2 (MM5) meteorological fields to examine the spatial distributions of the acidic pollutant concentrations in East Asia for the case of the long-lasting Yellow Sand event in April 1998. The present models simulate quite well the observed general trend and the diurnal variation of concentrations of gaseous pollutants, especially for O3 concentration. However, the model underestimates SO2 and NO x concentration but overestimates O3 concentration largely due to uncertainty in NO x and VOC emissions. It is found that the simulated gaseous pollutants such as SO2, NO x , and NH3 are not transported far away from the source regions but show significant diurnal variations of their concentrations. However, the daily variations of the concentrations are not significant due to invariant emission rates. On the other hand, concentrations of the transformed pollutants including SO4 2−, NH4 +, and NO3 are found to have significant daily variations but little diurnal variations. The model-estimated deposition indicates that dry deposition is largely contributed by gaseous pollutants while wet deposition of pollutants is mainly contributed by the transformed pollutants.
Keywords: CB-4 model; Regional acid deposition model; Emission database for global atmospheric research; Transformed pollutants;

Past and present-day biogenic volatile organic compound emissions in East Asia by Allison Steiner; Chao Luo; Yan Huang; W.L Chameides (4895-4905).
Biogenic volatile organic carbon (VOC) emissions from vegetation in East Asia are estimated for two contrasting land-cover scenarios: near present-day conditions derived from satellite data and pre-disturbed land-cover based on climatological parameters and plant functional type. Hourly fluxes of isoprene and monoterpenes are calculated on a grid of 60 km×60 km cells covering much of East Asia using meteorological conditions derived from a 12-month simulation of the region using regional climate model, monthly leaf area indexes, and the Guenther et al. (J. Geophys. Res. 101 (1995) 1345) ecosystem-dependent emission factors. Total present-day isoprene emissions are estimated at approximately 12 Tg C yr−1 and monoterpene emissions at 6 Tg C yr−1. These emissions are approximately 5.4 and 4 Tg C yr−1 lower than the estimated pre-disturbed emissions of isoprene and monoterpenes, respectively, largely due to the conversion of forested land to cropland. ORVOC emission estimates for the present-day scenario, obtained by assuming a constant ORVOC emission factor for all ecosystems, are slightly higher in magnitude than isoprene emissions. Present-day totals of combined biogenic and anthropogenic VOC emissions are generally larger than biogenic VOC emissions in the pre-disturbed scenario, indicating that human activities have led to a net increase in the atmospheric source of VOC in East Asia.
Keywords: Biogenic emissions; Volatile organic compounds; Asia; Land use; Isoprene;

Vertical and horizontal profiles of airborne particulate matter near major roads in Macao, China by Ye Wu; Jiming Hao; Lixin Fu; Zhishi Wang; Uwa Tang (4907-4918).
Vertical profiles, horizontal profiles and size distribution of airborne particulate matter were measured near major roads in Macao using DustTrak and TEOM monitors. A significant decrease in the concentrations of PM10, PM2.5 and PM1, as the height above the ground increases from 2 to 79 m, was found. At the height of 79 m, the concentrations of PM10, PM2.5 and PM1, decrease to about 60%, 62% and 80% of the maximum occurring at 2 m above the ground, respectively. However, the horizontal profiles near another major road revealed there was no significant trend of decrease in concentrations of particulate matter as the distance from the road increases. Over the total measured distance (0–228 m), the maximum decreases of PM10, PM2.5 and PM1 are only 7%, 9% and 10%, of the maximum occurring at 2 m from the road, respectively. The daytime averaged PM2.5 and PM1 contribute 66–67% and 51–60%, respectively, of the total PM10 mass after the particle readings by DustTrak were recalibrated by TEOM. It showed that fine particles and submicrometer particles contributed a major part of PM10 at the roadside in Macao, which is most likely attributed to the combinations of local sources including exhausted particulate matter from vehicles and resuspended fine dust, and secondary particles (sulfate, nitrate and ammonium) of regional scales.
Keywords: PM10; PM2.5; PM1; Vertical profile; Horizontal profile; Particle size distribution; Traffic;

The composition of landfill gas (LFG) was analyzed for vapor-phase mercury (Hg) (primarily in its elemental form, Hg0) and relevant environmental parameters from 42 out of 106 ventpipes placed across two different sectors of the Nan-Ji-Do (NJD) landfill site in Seoul, Korea during September/October 2000. Results of our studies showed that large quantities of Hg emanated through these ventpipes which were infiltrated deep into the waste layer. The mean concentration of Hg, computed using the data sets collected from 42 ventpipes, was 420 ng m−3 with a range of 3.45–2952 ng m−3. Because large differences were apparent in its concentration levels not only between the two sectors of 1 and 2 but also between the plain and slope areas, evaluation of the data was made by dividing them into four different categories, namely plain areas of sectors 1 and 2 and slope areas of sectors 1 and 2. By categorizing the data in such a manner, the emission fluxes of ventilated Hg were estimated for each data group at the NJD site. The flux values of Hg for each data group were distinguished so that the enhanced fluxes were observed in plain compared to slope areas. The computed LFG fluxes of Hg from the whole NJD site were on the order of 23 g on an annual basis. The overall results of our study suggest that the vent emission of Hg from the study site is comparable in magnitude to those reported previously (e.g., the Florida landfill sites in US), while the LFG emissions of Hg may not necessarily be the most dominant source in the NJD site.
Keywords: Mercury; Landfill; Infiltrated ventpipes; Waste; Emission;

Nighttime variations in HO2 radical mixing ratios at Rishiri Island observed with elevated monoterpene mixing ratios by Yugo Kanaya; Kenji Nakamura; Shungo Kato; Jun Matsumoto; Hiroshi Tanimoto; Hajime Akimoto (4929-4940).
HO2 radical concentrations were measured by a laser-induced fluorescence instrument for three nighttime periods during the intensive field campaign at Rishiri Island, Japan, in June 2000. The HO2 mixing ratio had temporal variations around its average of 4.2±1.2 (1σ) pptv and showed a positive correlation with the summed mixing ratio of four monoterpene species, α-pinene, β-pinene, camphene, and limonene, that sometimes reached 1 ppbv. Our model calculations suggested that ozonolysis reactions of monoterpenes were the main source of nighttime radicals and they explained 58% of measured HO2 concentration levels. The model roughly reproduced the dependence of the HO2 mixing ratio on the square root of the radical production rate due to the ozonolysis reactions of the monoterpenes. However, the absolute HO2 mixing ratio was significantly underpredicted by the model. We discuss possible reasons in terms of misunderstood RO2 chemistry, RO2 interference with HO2 observations, unknown radical production process associated by high NO2 mixing ratio, and the contribution of unmeasured olefinic species to radical production via their reactions with ozone.
Keywords: HO2 radical; Nighttime chemistry; Monoterpene; Ozonolysis reaction; Boundary layer;

Some results of snow chemical surveys in the Kunnes River valley, East Tienshan mountains, China by Jiang Fengqing; Zhu Cheng; Wei Wenshou; Osamu Abe (4941-4949).
Chemical surveys of snow were carried out in the upper reaches of the Kunnes River, a tributary of the Yili River in East Tienshan Mountains, China. Some surprisingly high values of sodium and potassium (K++Na+) ranging from 4.44 to 8.99 mg/l compared with other data from neighboring areas are detected. Moreover, some relative high values of SO4 2− with mean concentration 15.8 mg/l for new snow and 14.40 mg/l for deposited snow, ranging from 10.43 to 23.71 mg/l are also found. Therefore, it is inferred that the sodium and potassium (K++Na+) are in the forms of sulfate and that the sources of the sulfate are deserts and some dried lakes in Central Asia. It is also found that there is obviously spatial variation of ions such as K++Na+, Ca2+, SO4 2− and HCO3 . The concentrations of K++Na+ and SO4 2−, and that of Ca2+ and HCO3 have similar spatial pattern. The temporal pattern of ion concentration of new snow is considered to be mainly controlled by the depth and area of snow cover in the study area and in the areas to the west.
Keywords: Snow chemistry; Ions; Sulfate; Kunnes River valley; The East Tienshan Mountains; Central Asia;

Estimation of nitrogen dry deposition in South Korea by Soon-Ung Park; Young-Hee Lee; Eun-Hee Lee (4951-4964).
Dry deposition of nitrogen over South Korea has been estimated using a simplified chemical model and the K-mean clustering technique. The three consecutive daily mean National Center for Environmental Protection (NCEP) reanalyzed 850 hPa geopotential height fields without precipitation on the last day over South Korea are used for clusterings of synoptic patterns for the period of 1994–1998. The estimated long-term dry deposition of nitrogen by aggregating each cluster over South Korea is found to be about 530 eq ha−1  yr−1, of which 30%, 23%, 19%, 18% and 9% are contributed by HNO3, NH4 +, NO2, NH3 and NO3 nitrogen species, suggesting the importance of secondary pollutants of nitrogen species for dry deposition of nitrogen.
Keywords: K-mean clustering technique; Empirical radical concentration; National Center for Environmental Protection (NCEP) reanalysis data; Nitrogen species; Secondary pollutants;

A spatially explicit inventory of CH4 emissions was compiled for Australia to give net CH4 emissions of 85, 391 and 2609  Gg yr −1 from Tasmania, central-south and southeast Australia in 1997, respectively. These estimates were refined by applying the synthesis filtering technique to in situ surface CH4 concentrations measured at Cape Grim, (40.68°S,144.68°E). The refined estimates are 65, 249 and 1502  Gg yr −1 , respectively, with uncertainties of the estimates being reduced by 25%, 50% and 80%, respectively. Sensitivity analysis shows that the inversion results do not change significantly under a range of assumptions. The inventory is therefore considered to significantly overestimate net emissions from central-south and southeast Australia in 1997. We also conclude that in situ CH4 concentration measurements can provide definite constraints for estimating regional CH4 emissions in Australia.
Keywords: Synthesis inversion; Methane; Inventory verification; Australia; Kalman filter;

Emissions of nitrous oxide and methane from Antarctic Tundra: role of penguin dropping deposition by Liguang Sun; Renbin Zhu; Zhouqing Xie; Guangxi Xing (4977-4982).
During the austral summers of 1999 and 2000, we made measurements of methane and nitrous oxide fluxes from tundra soils in maritime Antarctica, using a static open chamber technique. N2O and CH4 fluxes from the non-ornithogenic moss soils averaged 0.8 and −8.7 μg m−2  h−1, respectively, in the summer of 1999 and 1.4 and 26.7 μg m−2  h−1, respectively, in the summer of 2000. N2O flux from the ornithogenic soils was approximately two orders of magnitude greater than that from moss soils and averaged 89.7 μg m−2  h−1, and CH4 flux was approximately one order of magnitude greater and averaged 227.9 μg m−2  h−1, indicating that high organic carbon and nitrogen compound of penguin droppings deposition in the soils resulted in high CH4 and N2O emissions as a result of biologic transformation. The relationships between the fluxes and environmental factors were discussed.
Keywords: Methane; Nitrous oxide; Soil; Penguin dropping; Antarctica;

Publishers note (4983).