Impact of forest fires on regional air quality in Southeast Asia     

Rajasekhar Balasubramanian Siao Wee See 《中国地球化学学报》2006,25(B08):221-222

Biomass burning, the burning of living and dead vegetation for land-clearing and land-use change, has been in practice in many tropical countries such as Brazil, Indonesia, Nigeria, and Mexico. Intense forest fires can also ignite subsurface organic soil components （e.g. peat）, which can continue to smolder long after the original surface fires are put out. Combustion of vegetation and peat has only recently been recognized as a major source of atmospheric pollution. The immediate effect of burning is the production and release of gases and particles into the atmosphere, in quantities that in some cases can be significant not only locally and regionally but also on a global scale. Vegetation fire emissions account for roughly half of the atmospheric constituents of hydrocarbon, carbon monoxide, nitrogen oxides, and precursors of tropospheric ozone and may be the second largest source of anthropogenic aerosols after the production of sulfates from SO2. As a result, there has been considerable interest in studying the contribution of forest fires to the production of air pollutants. In recent years, Southeast Asian countries have been affected repeatedly by episodes of smoke haze from forest fires in Indonesia. During 1997-1998, the region was again shrouded in a haze worsened by prolonged drought linked to the E1 Nino weather phenomenon. Satellite pictures confirmed that air pollutants, originating from fires covering an estimated 800000 hectares of southern Kalimantan, Sumatra, and Java, have been transported by southwesterly monsoon winds across neighbouring Malaysia and Singapore to as far as Thailand and the Philippines. The impact of these extensive fires on the health of the residents and ecology in the affected areas was substantial, costly, and possibly long lasting. Most of the research on the environmental aspects of biomass burning has been directed towards the tropics in Africa and America, specifically to the tropical rain forests of Brazil and to the savannas of Africa and South America.  相似文献   

Carbonation of Cl-rich scapolite boudins in Skallen, East Antarctica: evidence for changing fluid condition in the continental crust   总被引：2，自引：0，他引：2  

M. SATISH-KUMAR  J. HERMANN  T. TSUNOGAE  Y. OSANAI 《Journal of Metamorphic Geology》2006,24(3):241-261

Spectacular reaction textures in poikiloblastic scapolitite boudins, within marbles in the continental crust exposed in the Lützow–Holm Complex, East Antarctica, provide insights into the changing fluid composition and movement of fluid along grain boundaries and fractures. Petrographic and geochemical features indicate scapolite formation under contrasting fluid compositions. Core composition of scapolite poikiloblasts (Scp_I) are marialitic (Cl = 0.7 apfu) whereas rims in contact with biotite or clinopyroxene are meionite rich. Fine‐grained recrystallized equigranular scapolite (Scp_II) shows prominent chemical zoning, with a marialitic core and a meionitic rim (Cl = 0.36 apfu). Scapolite poikiloblasts are traversed by Scp_III reaction zones along fractures with compositional gradients. Pure CO₂ fluid inclusions are observed in healed fractures in scapolite poikiloblasts. These negative crystal‐shaped fluid inclusions are moderately dense, and are believed to be coeval with Scp_III formation at temperatures >600 °C and a minimum pressure of c. 3.8 kbar. Grain‐scale LA‐ICPMS studies on trace and rare earth elements on different textural types of scaplolites and a traverse through scapolite reaction zone with compositional gradient suggest a multistage fluid evolution history. Scp_I developed in the presence of an internally buffered, brine‐rich fluid derived probably from an evaporite source during prograde to peak metamorphism. Recrystallization and grain size reduction occurred in the presence of an externally sourced carbonate (CaCO₃)‐bearing fluid, resulting in the leaching of Cl, K, Rb and Ba from Scp_I along fractures and grain boundaries. Movement of fluids was enhanced by micro‐fracturing during the transformation of Scp_I to Scp_III. Fractures in fluorapatite are altered to chlorapatite proving evidence for the pathways of escaping Cl‐bearing fluids released from Scp_I. The present study thus provides evidence for the usefulness of scapolite in fingerprinting changing volatile composition and trace element contents of fluids that percolate within the continental crust.  相似文献   

Trace elements in natural organic-rich surface soils： Contributions from natural and anthropogenic sources     

Eiliv Steinnes 《中国地球化学学报》2006,25(B08):5-5

A large part of the Northem Hemisphere is covered by podzols and similar soil types, which have a surface layer characterized by high organic matter content. This layer is extremely important because it is the main source of plant nutrients. The elemental composition of the surface soil however is often strongly different from that of the underlying mineral soil, which may be due to a combination of natural processes and anthropogenic influence. Research in Norway over the last 30 years has contr/buted to the understanding of the relative importance of different factors in modifying the chemistry of the surface soil. The country is relatively pristine, but is substantially influenced in the south by atmospheric supply of pollutants from other parts of Europe. Vegetation is relatively uniform over large parts of the country, but climatic variations related to oceanic influence are considerable.  相似文献   

Fine-particle Mn and other metals linked to the introduction of MMT into gasoline in Sydney, Australia： Results of a natural experiment     

Brian Gulson David Cohen J. Michael Davis Ed Stelcer D. Garton Olg Hawas Alan Taylor 《中国地球化学学报》2006,25(B08):62-63

PM2.5 particulates were analyzed using accelerator-based ion beam methods for a suite of 21 species （H, C, Na, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Br, Pb） to evaluate the contribution to Sydney air associated with the introduction of MMT as a replacement for Pb. MMT was discontinued in 2004. Teflon filters continuously sampled for 7 years from 1998 to 2004 were analyzed from two sites： a suburb （Mascot） close to the Central Business District [CBD （n=718）] and a high trafficked area, and a relatively rural （background） setting, ～20 km west of the CBD （n=730）. Mean Mn concentrations in air at the background site increased from 1.5- 1.6 ng/m^3 to 〈2 ng/m^3 at the time of the greatest MMT use whereas those at Mascot increased from about 2 to 5 ng/m^3. From the maximum values, the Mn showed a steady decrease at both sites concomitant with the decreasing use of MMT. Lead concentrations in air at both sites decreased from 1998 onwards, concomitant with the phase out of leaded gasoline in 2002. A high correlation was obtained for the relationship between Mn in air and lead replacement gasoline （LRG） use （R2 0.83） and an improved correlation for Mn/Al＋Si＋K and LRG use （R2 0.93）. With Mn concentrations normalized to background values of Al＋Si＋K to account for the lithogenically-derived Mn, the proportion of anthropogenic Mn was -70%. Changes for Mn and Pb in the particulates are attributed to the before-during-after use of MMT and decreasing use of Pb in gasoline.  相似文献   

Calibration of Four Species of Tillandsia as Air Pollution Biomonitors   总被引：1，自引：0，他引：1  

Eduardo D. Wannaz  María L. Pignata 《Journal of Atmospheric Chemistry》2006,53(3):185-209

Many organisms have been used as bioindicators of atmospheric contamination, with moss and lichen species being the most common. However, studies using epiphytic vascular species of Tillandsia have shown a good correlation between the presence of pollutants and the bioindicator's response. Therefore, the aim of our investigation was to calibrate and compare the response of four Tillandsia species of Argentina to ascertain whether they could be used as atmospheric contamination biomonitors. For this, we analysed the correlation between the levels of heavy metals in total atmospheric deposition samples and: a) their rate of enrichment; b) the physiological response of the plant samples. Tillandsia samples collected from a non contaminated area in the province of Córdoba were transplanted to four areas in the capital city with different sources of pollution (industrial or traffic emissions). They were exposed for a period of 3 to 6 months after which the concentrations of Pb, Ni, Fe, Zn, Cu and S as well as the physiological parameters of foliar damage were determined. Simultaneously samples of total atmospheric deposition were also taken.The highest level of metal enrichment was found in T. capillaris followed by T. tricholepis, T. permutata and T. retorta. Also, the use of a foliar damage index proved to be effective and could be a useful tool to evaluate different levels of atmospheric quality in these species. The rate of heavy metal deposition was higher in the industrial area for all metals except for Zn whose values were higher in areas with high levels of traffic.  相似文献   

New aerosol particle formation via certain ion driven processes     

A. Luts  T.-E. Parts  M. Vana 《Atmospheric Research》2006,82(3-4):547

Ions can speed up the formation of aerosol particles. The former studies have mainly concerned on the role of the ion charge itself. We have studied the possible (additional) role of the actual small air ion spectrum shape, and the quantitative role of ion–ion recombination pathway. By means of our ion evolution model, formation of new species (H₂SO₄)_n(NH₃)_m(HNO₃)_k via ion–ion recombination was investigated. The model shows how the generation rate of the new species depends on the concentrations of H₂SO₄ and NH₃, and how it depends on the tropospheric background aerosol situation. The rate can be up to a few new neutral complexes per cubic centimeter and per second. New particle generation via ion–ion recombination provides an extra channel, especially for the clean atmosphere. Former results have shown that such situations are often present in Antarctica. Our aerosol spectrum measurements reveal a number of similar non-Antarctic results. Sometimes, such situations are followed by aerosol bursts, which may be (partly) due to an ion–ion recombination channel.  相似文献   

广州地区近地层湍流输送的特征   总被引：1，自引：1，他引：0  

刘海涛  朱超群 《热带气象学报》1998,14(3):233-238

利用风温梯度观测资料,以相似理论为基础,采用迭代方法得到普适函数Φ（ｚ／Ｌ）的半径验表达式,对近地层总体输送系数的牲进行了分析,求得了与风速、温度的拟合关系,并利用实测资料地其适用性作了检验。  相似文献   

森林排放非甲烷碳氢化合物的初步研究   总被引：15，自引：0，他引：15  

白建辉  王明星  John Graham  Ronald G. Prinn  黄忠良 《大气科学》1998,22(2):247-251

1995年6月至1996年4月,在广东肇庆鼎湖山自然保护区每两周采样一次,利用0.8 L不锈钢采样钢瓶采样和气相色谱法分析、研究森林排放的非甲烷碳氢化合物的浓度。结果表明,森林排放的异戊二烯有明显的季节变化,其浓度与温度有明显的正相关关系。  相似文献   

山东枣庄地区辐射逆温及其影响   总被引：1，自引：1，他引：0  

郑全岭  崔秀兰 《气象科学》1998,18(2):156-161

本文运用1981年11月17日-12月16日共30天实地考察资料,分析了山东枣庄地区冬季辐射逆温时空变化规律。并探讨了辐射逆温的生成与云量、风速的关系。  相似文献   

Helium and argon isotopic geochemistry of Jinding superlarge Pb-Zn deposit   总被引：5，自引：0，他引：5  

Ruizhong Hu  G. Turner  P. G. Burnard  Hong Zhong  Zaojun Ye  Xianwu Bi 《中国科学D辑(英文版)》1998,41(4):442-448

The study results of He and Ar isotopes from fluid inclusions in pyrites formed during mineralization stage of Jinding superlarge Pb-Zn deposit in west Yunnan, China are reported. The data show that the⁴⁰Ar/³⁶Ar and³He/⁴He ratios of fluid inclusions are respectively in the range of 301. 7–385. 7 and 0. 03–0.06Ra, suggesting the oreforming fluid is a kind of air saturated meteoric groundwater. On the basis of research on coupled relationships among He, Ar, S and Pb isotopes, the evolution history of ore-forming fluid of the deposit can be summarized as (i) air saturated meteogenic groundwater infiltrated down and was heated→ (ii) leached S, C and radiogenic He, Ar from the basinal strata → (iii) leached Pb and Zn from mantle-derived igneous rocks located in the bottom of the basin→ (iv) ore-forming fluid ascended and formed the deposit. Due to this process, the isotope signatures of crustal radiogenic He, atmospheric Ar (with partial radiogenic⁴⁰Ar), crustal S and mantle-derived Pb remained in the ore-forming fluid. Project supported by A30 Project of the National Climbing Program of China and University of Manchester.  相似文献