Sampling of ambient particulate matters were conducted along with the measurement of NO2 at three different sites in Phnom Penh including the central part of downtown, residential and river side areas. Day and night samplings of total suspended particulates (TSP) were conducted in the central downtown. Concentrations of TSP and NO2 as well as chemical composition of particulates, i.e. polycyclic aromatic hydrocarbons (PAHs) and heavy metals, were measured in order to discuss the contributions of emission sources. TSP concentration in the central downtown area was 100-250μg/m3, which was higher in daytime than nighttime, being similar to the concentration change of elements from soil such as Al, Ca and Fe. This suggests that TSP is mostly road dust or soil re-suspended by wind. On the other hand, both concentrations of PAHs with four or more aromatic rings and their mass fractions in particles were found to be higher during the night. This may be attributed to the emissions from diesel and other small generators for supplemental electricity, from kerosene uses for lighting and from biomass fuel for cooking, etc. The Mekong and Tonle Sap rivers may influence the ambient air transport and pollutant dispersion in Phnom Penh. The concentration of PAHs in Phnom Penh was approximately forty times higher than Kanazawa, Japan, and six times higher than Bangkok, Thailand.
Acid Deposition Monitoring Network in East Asia (EANET) started the monitoring activity regularly in January 2001 after the preparatory phase activity since 1998. The objectives of the network are to create a common understanding of the state of acid deposition in East Asia, to provide useful input for decision-making at local, national and regional levels aimed at preventing or reducing adverse impact on the environment caused by acid deposition, and to contribute to cooperation on the issues related to acid deposition among the participating countries. At present, EANET consists of thirteen participating countries including seven countries in Southeast Asia. Wet deposition and air concentration monitoring are implemented in 46 and 35 sites, respectively. Those monitoring are carried out according to the manuals prepared by the Scientific Advisory Committee, which is composed of the scientists from participating countries. EANET activities are introduced in detail as one of the inter-governmental programs for environmental issues in the region including the Southeast Asian countries.
Lake Tonle Sap, the largest lake in Southeast Asia, has been closely associated with the lives and culture of Cambodian people and society. A great amount of aquatic resources arising from its high biodiversity has supported them since the Khmer Dynastic Time to the present. However, because problems of environmental pollution, and atmospheric pollution in particular, have become worse within a short space of time in Cambodia due to rapid development of tourism of the Angkor Monument Complex for instance, its harmful effect to the natural environment has been of recent concern. Rapid deterioration of the natural environment will probably trigger a certain change of the lake ecosystem, and the change might lead to a fatal damage to the plentiful aquatic resources. The present article describes the preliminary results of the research missions “Evaluation of Mechanisms Sustaining the Biodiversity in Lake Tonle Sap” from 2003 to 2005. On the basis of these results loss and damage of the natural environment and biodiversity of the lake are estimated, along with the progress of atmospheric pollution.
Thailand is the world leader in natural rubber production and export. Intermediate products from natural rubber industries include ribbed smoked sheets (RSS) , air dried sheets (ADS) , block rubber, crepe rubber, and concentrated rubber latex. In these production processes, many environmental problems arise. These include air, water, and odor pollutions. In this article, environmental problems and existing control techniques in each rubber production are reviewed. In rubber sheet drying industry, main concern is the smoke particles from fuel wood burning because of the presence of hazardous components such as PAHs (polycyclic aromatic hydrocarbons) associated with the particles. The PAH concentration is very high in the workspace and this could have adverse effect on workers' health. Moreover, the wastewater in rubber drying cooperatives is not treated properly. Appropriate technologies are needed in dealing with both smoke particles and wastewater problems. In rubber latex industry, main concern is wastewater but it is generally well treated. The odor problem arising from ammonia used for latex preservation remains, however, unsolved. In rubber glove industry, main problem is the wastewater and it is treated the same way as in rubber latex industry.
Methodology for an effective and substantial technology transfer to developing countries in East Asia is discussed from the viewpoint of monitoring of air and water pollutants. First example of technology transfer is an introduction of passive samplers at Shenyang, China for monitoring SO2 concentration. Second example is the Hi-volume air sampling to evaluate the aerosol concentration and chemical compositions in Bangkok, Thailand. Third was a portable UV-COD analyzer for river pollution at Cavite, Philippines. In these successful technology transfers, the most important factors in transferring technologies to adequate sites (countries) are low cost, maintenance-free and simple operation for analysis. However, we have to keep in mind the objectives of the technology transfer. Most of ODA confine their target on the pollution control officers in national / local governments. But private companies actually pay the cost for installing the waste gas treatment facilities. Therefore promotion and encouragement of pollution control engineers in private companies are very important when we have pollution control seminars in developing countries.
Field measurements of size-resolved particle number concentrations of PM2.5 and ultrafine particles (UFPs) (<0.3μm) were performed using an ultrafine particle counter (UFPC) at a roadside and indoor / outdoor of a building located about 50m away from the roadside. Similar behavior of both UFP and PM2.5 were found for number concentrations at all measuring sites, and it was made clear that the wind speed influences UFP concentration more significantly than rainfall. In addition, high correlations between UFP concentration and nitrogen monoxide (NO) and elemental carbon (EC) concentrations indicated that the particles emitted from motor vehicles, particularly diesel emission particles, are transported near the building and penetrated into the indoor space of the building. Furthermore, since the indoor / outdoor ratios (I / O ratios) of UFP and PM2.5 increased when a fan ventilator was used, it was thought that UFP and PM2.5 come into the building through the gaps between windows and doors with the walls.
Aerial observations of atmospheric pollutants were carried out over the seas between Japan and the Asian continent as well as over the coastal region of China. The data of ammonium to sulfate ratio were compared with those taken at Fukue and Okinawa by use of AMS. Aerial observations of atmospheric pollutants over China and the East China Sea close to the continent revealed very high concentrations of sulfate, nitrate, and ammonium over there. It was shown that the concentration of sulfate was nearly equal to that of ammonium in China and over the East China Sea. This fact suggests that the aerosols over China were rich in sulfate and well neutralized with ammonia. Over the East China Sea, sulfate was in fine particles and still to be neutralized well with ammonia, whereas nitrate was present mainly in coarse particles. Ammonium to sulfate ratio became lower when the air mass was transported long range from the continent to the Pacific. This indicates that there is addition of sulfate (formation from gaseous SO2) within the air mass whereas only removal processes exist for ammonia gas during the transport.
New type of Resin Wool Filter (RWF) retains a high electrical charge density and persists organic droplet challenge. The RWF consists of merino wool fibers, polyester fibers, and p-t-butyl-phenol-formaldehyde (PTBP) resin particle, and the detailed local charge distribution of RWF and the effect on the collection efficiency are not yet well understood. In the present work, the charging state of RWF was studied by observing the deposition sites in RWF by using negatively / positively charged particles with a known size and a known number of electrical charges. As a result, the polyester fibers and resin particles adhering on the polyester fibers are charged negatively while the wool fibers retain positive charge. The resin particles adhering on the wool fibers are negatively charged or polarized by the charge of wool fibers. Furthermore it is found that the induced force prevails over the Coulombic force for singly charged 0.309-μm particles so that the particles with unit positive charge deposit on the surface of positively charged wool fibers.
We performed long-term continuous monitoring of aerosols at Tango Peninsula (Kyoto Prefecture) , in the coastal area of the Sea of Japan. We conducted long-term automatic continuous collection of aerosols with particle size segregation (<2.5μm and 2.5∼10μm) by means of a tape filter. A high-sensitivity inductively coupled Argon plasma mass spectrometer was used for the trace metal analysis. With this system, we could analyze trace metal concentrations from half-day or one-day samples of aerosols. High time resolution data of trace metal concentrations as well as trace metal concentration ratios can be used to evaluate long-range transport. A heavy Kosa event was observed in March and April 2002. We compared the variations in the concentrations of water-soluble inorganic ions as well as the trace metal components during the Kosa event with those collected during non-Kosa periods. Sulfate and ammonium ions, present as (NH4)2SO4, were the major water-soluble inorganic ions in aerosol particles with the diameter of less than 2.5μm, indicating that neutralization had advanced greatly. Chlorine loss was observed in aerosol particles of 2.5∼10μm in diameter during the non-Kosa period. There was a clear difference between soil-originated and anthropogenic trace metal components. During Kosa events, concentrations of almost all trace metals increased ; however, sometimes an increase in the anthropogenic trace metal component was observed without a corresponding increase in the soil-originated trace metal component. From backward trajectory analysis, when sulfate and lead concentrations were both high, the air mass had traveled from central China, and then across the Bohai and Yellow seas and the Korean Peninsula. Concentration ratios of Pb / Cd and Th / U showed characteristic values in the case of a Kosa event when the air mass had traveled over central China and the Korean Peninsula. Thus, trace metal concentration ratios are valuable for evaluating long-range aerosol transport.