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vol.50-1(2012/5/31)
| The Disaster Situation Outline of the Building and Equipment Caused by the Great East Japan Earthquake |
| The Great East Japan Earthquake generated on March 11, 2011 brought damage to much of the northeast area of Japan. The disaster of building and equipment, suffered by the East Japan Calamity, were caused on the earthquake and specially on tsunami. Furthermore, a lot of radioactive contaminants are emitted from the Fukushima Daiichi Nuclear Power Plant caused by the earthquake and tsunami, and it has been a still serious problem. This paper describes the outline of disaster situation of the Great East Japan Earthquake, and the disaster of the building and its equipment. |
| The damage situation relevant to an air conditioning facility |
| Last year, the magnitude 9.0 powerful earthquake occurred in the Pacific coast of Tohoku, Japan. The incident took place at around 14:46 JST, Friday, on March 11, 2011. The epicenter was detected in the Sanriku coast of Tohoku. It was the most devastating earthquake ever recorded in Japan, causing land subsidence, soil liquefaction, and even triggering a disastrous tsunami. This tsunami had greatly affected a wide-ranging seabed and had damaged infrastructures, sweeping away most cities. Furthermore, the total number of victims, which is composed of the missing people and dead people, reached up to around 19,000. Our report covers the following things: 1.the characteristics of the earthquake and the extent of its damage; 2. the cause and effect of the damages on the air conditioning units, particularly the ones hanging on the ceiling, which were considered a major threat to life and safety; 3. solutions to prevent such damages. Interviews and surveys were conducted to obtain necessary information about these matters. In response to the disaster, the authorities have to be more alert in making preparations on dealing with earthquakes and other related incidents. Comprehensive measures should certainly be applied to secure the lives of the people and avoid untoward damages that the Tokai and other earthquakes will be making in the future. |
| Environmental Pollution Caused by Radioactive Substances and its Countermeasure Techniques |
| Fukushima and the neighboring area have been polluted by the accident of the nuclear plant and there are some locally contaminated areas called as “hot spot”. Although the radioactive substance that piled up on the road or the roof of buildings is moved away by the rain, the decontamination is indispensable to prompt reduction. Especially, the decontamination in urban areas is an urgent subject. It is necessary for people in Fukushima to decontaminate for reducing radioactivity level. So, a survey research was conducted to find the actual condition of contamination, the radioactive concentration of the soil and the plant in urban area. It turned out that the radioactive concentration of soil or plants were heavily polluted by caesium-134 and 137, and iodine-131 was already disappeared by its lifetime. Especially, cesium-134＋137 was ranged 3400 Bq/kg at the surface of soil in garden, however, it was remarkably decreased in the deeper point at 10cm and ranged 23 Bq/kg, and we could not detect the cesium at 15cm. And it turned out that the evergreen plants have been polluted at high radioactive concentration and decontamination by cutting down the plant was decreased by 14% average at the point of 100cm from ground surface. In present study, we also aimed at decontaminating the substance by a high-pressure cleaning machine for terrace in houses in Fukushima prefecture, and we also aimed at examining the decontamination effect of the washing method. In the measurement, the level at drain where radioactive lever were high was decreased from 0.64 to 0.24[μSv/h] by decontamination with a high pressure washing machine, it meant that radiation level was reduced by 61.8% respectively. |
| Radioactive Substances in Atmospheric Aerosol Particles Collected at Kanagawa Area before and after the Great East Japan Earthquake |
| Atmospheric aerosol samples were collected at Shonan campus of Tokai University in Kanagawa, Japan from 7th to 20th March in 2011, even when the Great East Japan Earthquake occurred and subsequent accident happened at Fukushima Daiichi Nuclear Power Plant, approximately 260 km apart from the sampling site. This study aimed to demonstrate the radioactive contamination of the aerosol samples by identifying radioactive nuclides and measurement of radioactivity of the collected samples. Counting rate of collected samples was measured from the surface of particle trapped on a quartz fiber filter by using GM survey meter. Remarkable increase in counting rate was observed after the accident with a maximum of 6.0×104 cpm in the daily aerosol sample collected from 13th to 14th March. In the contaminated samples, 132Te, 131I, 132I, 134Cs and 137Cs were identified by Germanium detector. Size distribution of the nuclides was also obtained from size-fractionated samples collected by Andersen sampler and showed mass median diameter nuclides were approximately 1 micro meter. A significant change was not found in acute toxicity of water extracts of aerosol samples to Vibrio fischeri by the contamination. The data presented here must contribute to further discussion on an environmental behavior of and assessment of internal exposure to the radioactive nuclides emitted and transported from the power plant. |
| Development of Surface Particle Counter and its Performance |
| Particle contaminants (Size: 10-100 μm) can cause the quality defects of products in many industries such as optical machine assembly and coating process in car productions. The authors developed a new measurement instrument that can measure surface particle concentration on a plate. It can be also applied for ISO/FDIS 14644-9. This paper reports the introduction of the new instruments and its performance of counting efficiency. |
| Problem and scope on deodorization technologies applied for indoor environment |
| This paper provides an overview of deodorant methods based on the principles of ventilation, adsorption, absorption, sensory deodorization and oxidization, and especially explains the main features of the methods as follows. 1) Adsorption method and the degradation of activated carbon The enhanced activated carbon is called as impregnated activated carbon. Impregnating agents deteriorate easily in general environments, the degradation of its chemical substance removal and deodorization capabilities occurs early. 2) Oxidization methods and the safety of oxidizing species or byproducts Oxidization methods available in deodorant equipment are categorized into the following systems: combustion, ozonolysis, oxidizing species, photocatalyst method and ion emission one. In the ozonolysis or oxidizing species method, the major concerns are the density of ozone or species supply and byproducts resulting from the degradability or ozonolysis of contaminated substances. In both methods, it is essential to monitor these issues and confirm the safety of the methods. In addition, the paper focuses air cleaners, deodorant agents and toilets with a deodorant function as examples from among deodorant products that employ the above-described technologies and discusses their capabilities. Air cleaners and deodorizers that embody an automatic physical adsorbent exchanger and an automatic chemical adsorbent feeder are also introduced as highly anticipated new technologies. |
vol.50-2(2012/7/31)
| Performance of temporary house |
| For people who lost their houses by the Great East Japan Earthquake which occurred on March 11, 2011, 50,000 or more temporary houses were built in three prefectures of the Tohoku district. Most temporary housing units are terrace houses, the distance between buildings is narrow, and the performance of the thermal insulation does not comply with the next-generation energy-conservation standards. Therefore, we are anxious about the possibility many problems may occur, such as thermal environment, indoor air environment and sound environment problems. This paper provides the basic performance of temporary housings and questionnaire survey. |
| Indoor thermal environment of temporary houses built after Great East Japan Earthquake in 2011 |
| This research aims to propose the optimal environmental design method of temporary housing and show how to improve the environmental policy, after clarifying the relationship between the healthy situation of residents living temporary housing and the indoor thermal environment and indoor air quality. Therefore, a questionnaire, interviews, and environmental measurement for temporary housing in Sendai city, which is located in Miyagi prefecture, were carried out. This paper reported the measured results of indoor temperature and humidity, and occupants’ behaviors related to thermal environment in the temporary housing during the summer, fall and winter seasons of 2011. It was found the relationships between indoor temperature profiles and occupants’ behavior such as using air conditioner, opening or closing windows and so on from the measured results. From summer to fall season, indoor temperatures were decreasing according with the outdoor temperature. During winter season the indoor temperature was maintined around 20℃ during heating time. However after heating equipment was turned off, the indoor temperatre decreased rapidly. On the basis of investigated results, the optimal environmental design method of temporary housing could be provided and the methodology to improve the environmental policy will be shown. |
| The actual condition of the fungus contamination in temporary houses |
| The Great East Japan Earthquake generated on March 11, 2011 brought damage to much of the northeast area of Japan. The required number of temporary houses is more than 50,000. Many disaster victims will have to reside in temporary houses for the near- to long-term future. Mould contamination is expected to be an ongoing problem, especially given increased residential humidity resulting from the flood damage generated by the associated tsunami. This paper describes the results obtained in a survey of 40 temporary houses in Sendai-shi, Miyagi in August and October, 2011. We report that in 40 tested houses, fungal concentrations exceeded 1000 cfu/m3 in 45 of 66 rooms (70%). Thus, indoor environmental fungal growth, especially by xeric fungi, may present a serious concern for residents of temporary housing. |
| The actual condition of the chemical contamination in temporary houses |
| In Japan, the Great East Japan Earthquake had occurred on March 11th in 2011. There were serious damages in seaside cities of the Pacific Ocean in Tohoku district. Many people in these areas had lost their houses and more fifty thousand temporary houses were built in three prefectures of the Tohoku district. We are anxious about the possibility several problems may occur, such as indoor thermal environment and indoor air quality as well as sound environment problems. This research aimed to investigate the indoor air quality, especially VOC concentrations in indoor air in the temporary residential housings. In summer in 2011 and winter in 2012, measurements have been conducted in the temporary housing in Sendai and measuring results were compared with guideline value in Japan. As a result, TVOC concentrations in the most houses were over tentative guideline value in Japan, 400μg/m. |
| Risk Based Approach applied for Pharmaceutical Manufacturing of Highly Potent Products |
| Many pharmaceutical products have been manufactured in multi-used facilities where there is the risk of cross contamination. Increasing the development of the highly potent APIs (active pharmaceutical ingredients) such as genotoxic and carcinogenic has created a vital need for the scientific and risk based approach for properly managing the risk of cross contamination. Consulting ISPE's Baselin(R) Guide Risk-MaPP (Risk Based Manufacturer of Pharmaceutical Products) which provides a scientific risk-based methodology based on ICH Q9 to manage the risk of cross contamination, this document introduces an example of the risk assessment applied to air handling system in the pharmaceutical facilities. |
vol.50-3(2012/9/30)
| Basic Study of distinction between conductive particle and non-conductive particle by means of light scattering |
| Recently, the demand for Lithium-ion secondary batteries has risen rapidly. In the Lithium-ion secondary battery manufacturing process, it is indicated that conductive particles cause internal shorts which is one of the factors of its combustion. So in this manufacturing process, it is important not only to count the number of particles but to distinguish conductive particles from non-conductive particles. We calculated the distribution of the scattering of light from conductive particles and non-conductive particles respectively and we found out that the ratio of forward scattering intensity to backward scattering intensity depends on the conductivity of particles, which indicates the possibility of the distinction between conductive particle and non-conductive particle by means of light scattering. |
| Study on Odor Characteristic and Photocatalyst Decomposition of Nicotine |
| From the threshold dilution ratios of gaseous components in a tobacco smoke, we estimated the substances contributing to the odor in an environmental tobacco smoke (ETS). In the side-stream smoke, acetaldehyde was found to contribute most to the odor (approx. 70%), while nicotine in ETS was shown to be a lower contributing substance to about 1/30 of the odor of acetaldehyde. It was also confirmed that the odor threshold value of nicotine was 80 μg/m3 (0.011ppm; 0°C, 101.33kPa), and that, under the nicotine concentration of 300 μg/mc3 in the air, any correlation did not exist between the nicotine concentration and the odor concentration, proving that the other substances than nicotine made a greater contribution to the odor. In continueing, photocatalytic technology was applied to reduce nicotine. Using photocatalytic units with UV lamps placed at both sides of TiO2 photocatalytic filter, we performed a decomposition experiment of nicotine supported on the catalyst. It was found that nicotine almost was oxidized to finally decompose to carbon dioxide through nicotinic acid and cotinine although the decomposition rate was as much extremely slow. The amount of noxious carbon monoxide produced at the same time was only in such a small quantity as could be ignored in a ventilated atmosphere. |
| The performance and effect on indoor air quality of the smoking booth equipped a plasma deodorization air cleaning equipment |
| In recent years, it becomes important to separate a smoking area from the working space for maintaining indoor air quality. The installation of the exhaust fan and duct, initial cost, energy saving, environmental effect, etc make it difficult for the separation of smoking and non-smoking area in an existing building. In this study, a PLASMA-DASH-SIGMA [developed by Nittetsu Mining Co.,Ltd] equipped in a smoking booth was applied in the actual scale test room to investigate the removal characteristics by measuring environmental tobacco smoke. As a result, the measurements of CO, CO2, particles, VOCs, and odor in the non-smoking area in the test room showed the less influence to the indoor air quality by using smoking booth equipped the air cleaning equipment in the room. |
| Proposal of cleanbooth with return air system and the opening system which don't influence ambient surroundings |
| Cleanbooths are used as the local clean environments. However, they exhaust the air used in the booths from openings, and they sometimes influence ambient surrounding airflow distribution. Especially when cleanbooths are used in cleanrooms, this exhaust airflow may bring significant contamination problems. In this work, cleanbooth with return air system and the opening system which don't influence ambient surroundings were proposed and their performance were studied with theoretical model and numerical simulation technique. As the result, it was found that proposed systems achieved a good environment separative ability. These systems are also applicable to the automatic production machine booths. |
| The technical trend and prospects of the lithium ion battery for EV propulsion |
| Currently, vehicle faces 3 main problems; global warming measures, exhaust gas pollution and break-away from oil consumption for energy security problem. Vehicles with electric power train such as EV, HEV and plug-in HEV are expected to come into wide use to solve the upper problems. Battery performance and cost are one of the key factors to determine whether the vehicle with electric propulsion system come into wide use or not. This report introduces characteristics and conditions of batteries required as traction battery systems for battery electric vehicle, hybrid electric vehicle and plug-in hybrid electric vehicle. Current status of the lithium ion battery for traction battery system is described and problems of the lithium ion battery to be solved are also discussed. |
vol.50-4(2012/11/30)
| Radioactivity released from the Fukushima Daiichi Nuclear Power Plant accident and making of JACA guideline on exchanging work of contaminated air-filter |
| On March 11, 2011, a serious accident began at the Fukushima Daiichi Nuclear Power Plant (Fukushima-1 NPP) after a huge tsunami hit the plant as a result of the M9.0 earthquake. A large amount of radioactive nuclides, iodine, cesium, etc, were discharged from the Fukushima-1 NPP to atmospheric environment, and those moved into prefectures in the Tohoku and Kanto regions. The air-borne cesium and a part of iodine as being aerosol are trapped by air-filters and the radioactive nuclides may expose workers at the exchanging work of filter units. Furthermore, exchanged filters are not easily put into discard. On July, 2011, the JACA built a committee for making the guideline to suggest radioactive safety on work and treatment of exchanged air-filter device contaminated by radioactivity, and the committee released the guidelines on November. This paper describes the outline of radioactivity released from Fukushima-1 NPP and the making progress of JACA guideline. |
| Actual situation of the air filter that was contaminated with radioactive material |
| Japan Air Cleaning Association announced the guide on response to the accident of Fukushima Daiichi Nuclear Power Plant. This paper describes the following items. (1) The actual state of the air filter replacement (2) Situation of the contamination by type of air filter (3) Questionnaire results about air filter that is stored sites (4) Answers to common questions asked from customers |
| Simple Measurement of the Radioactivity on the Air Filter for Level Discrimination |
| The simple valuation method of the radioactivity on an air filter which was contaminated by the Fukushima Daiichi Nuclear Power Plant accident is required. We measured the radiation dose rate from a filter side, calculated the conversion coefficient which presumes the radioactivity on a filter using a 1-cm dose equivalent rate constant, and performed verification by survey. The value evaluated by this method and the quantitative analysis value by germanium semiconductor detector were equal to the rough value level. Since form of an air filter is complex, this method considers that we are practical. In addition, we explained instructions at the time of the measurement and revision by the aging of measurements. |
| Waste Air Filters and its Management |
| After the Fukushima Daiichi Nuclear Power Plant Accident, the Act on Special Measures concerning the Handring of Radioactive Pollution for the radioactively contaminated wastes was drafted and immediately binged into force. By the reason with respect to the enforcement of this New Law, the traditional Waste Management Act was enhanced and applied side by side to dispose the great majority of radioactively-contaminated wastes. In accordance with this New Laws, the waste disposal was sorting with the application of radioactive concentration(Bq/kg) and without the radioactive dosage(Sv/h). And then, the radioactively-contaminated wastes over 8,000Bq/kg became sorting into the Designated Wastes, on the other hand, in the case of out of the application, these wastes became the general industrial wastes. Now, let’s consider the disposal process of the radioactively contaminated Air Filter, these wastes are able to sorting into the recyclable materials, burnable substance, and its landfills using by the New Law. And if the radioactively contaminated Air Filter has set down the Designated Wastes, the national government shall be responsible for the cost relating to the storage management and retention time of it, but in these cases, the Air filter suppliers and users have to keep these wastes for a long time. Therefore, these processing methods are facing a strong criticism from the Japanese peoples, and these indecisive and defective measures Acts are not only causing the great distress to Air filter suppliers and users, but also plunging into the indeterminable situation. |
| Support and Future Prospects of JACA |
| Japan Air Cleaning Association (JACA) has established guidelines for handling of the air filter that has been contaminated with radioactive material in November 2011. Many air filter because it was contaminated with radioactive material, it has been stored inside the building can not be recycled or disposed of as industrial waste. We report on the well-known activity of the guidelines established by JACA, about the outlook for the future on how to dispose of contaminated air filters. |
| Principles and characteristics of light scattering particle counters |
| This article describes basic principles and characteristics of light scattering particle counters. Development of semiconductor ultra-fine processing technology required evolution of particle measurement technology, and we have improved it. This article describes improvement of the minimum detectable particle size, and improvement of the size resolution, and some improvement of liquid-borne particle counters. It also describes the views on the limits of the minimum measurable particle size of the current technology. Because the measurement using particle counters is easy to operate and easy to get the results compare with other measurement methods, the data errors occurred from that are often overlooked. So, thie article describes the main factors of errors. The measurement of the liquid-borne particles is often more difficult than that of the airborne particles. So, this article describes the main attention on the use of liquid-borne particle counter. |
| Onsite scanning of HEPA filter mounted on class II biological safety cabinet by particle counter: is it feasible? |
| Integrity of high efficiency particulate air (HEPA) filter mounted on class II biological safety cabinet (BSC) is one of three major protection barriers for workers in biomedical field and for the environment: air tightness of the casing, integrity of the HEPA filters, and air barrier at the front opening. The internationally specified method for certifying integrity of the HEPA filter, is to scan downstream of the filter with a photometer after loading polydispersed polyalphaolefin (PAO) aerosol on to the upstream of the filter. In Japan, a significant fraction of onsite certifiers of class II BSC still utilizes particle counters instead for this purpose. Recently, on this journal, Suzuki et al. reported a scanning method of HEPA filters in the clean room setting using a particle counter. Since certifiers of BSC HEPA filters may be mislead by their report, we reevaluated their method, if it can be applicable to the BSC certification. Even after modifying parameters, we could not find out a practical condition to scan HEPA filters by a particle counter with the specified sensitivity. Both users and BSC certifiers should realize that HEPA filter testing by particles counters is significantly less sensitive than internationally required and is endangering workers in biomedical laboratory and environment by potential failure in detecting defective HEPA filters. |
vol.50-5(2013/1/31)
| Current status of a commercial humidifier and handling of an evaporative humidifier in Japan |
| All humidifiers have been classified into steam, spray and evaporative type, and the various types of humidifiers have been developed depending on the specific application. Here is a brief introduction of the main types of humidifier used in public health and industrial air-conditioning. Furthermore, since an evaporative humidifier has been used more than 90% in office, school and health-care facility for the elderly in Japan, we mention some features and handling-care-points of an evaporative humidifier for you to use it in a hygienic way. |
| Measurement of microbe in AHU using vaporization type humidifier |
| Recently an application of a humidifier in a winter season becomes required. We know that a humidifier is polluted by a microbe than past literatures. Therefore at first we researched various conditions. And next we measured microbes in an air handling unit using vaporization type humidifier. Results were as follows; (1) Adhesive microbe --The surface concentrations of bacteria and fungus were more than 104cfu/m2. --The concentration of evaporative himidification module surface tended to be higher than the coil surface. (2) Airborne mocrobe --The concentration of evaporative humidification module outlet air tended to be higher than the coil outlet air. |
| The Measure Method of Microbial Contamination for an Evaporation Type Humidifier |
| The number of adoption of evaporation type humidifiers is increasing in recent years. Contamination of microbes is pointed out while an evaporation type humidifier has energy saving and a space-saving advantage. This paper introduces about the example of the measure against to microbial contaminations by UVGI, microwave, and silver ion, after describing the present condition and its measure method of the microbial contamination in an evaporation type humidifier. |
| Study on Microbial Contamination Measures in the Humidifier using Extremely Low Concentration Hypochlorous Acid Water |
| In late years, the adoption of the water humidification method increases. However, when adopting a water humidification method, the microbial contamination in the humidifier becomes the problem. On the other hands, it is reported that extremely low concentration hypochlorous acid water is useful for sterilization. In this study, the extremely low concentration hypochlorous acid water is used for humidifier to inhibit the mocrobial growth. This paper describes the effect of inhibition of microbial growth in humidifier system by using this water. |
| Computer Visualization: Characteristics of Visualization Techniques and Advanced Visualization |
| Computer visualization is widely used to analyze datasets obtained from measurements and numerical simulations. However, the increasing size and complexity of datasets makes it difficult to obtain appropriate visualization results by trial-and-error. In this report, we introduce the characteristics of basic visualization techniques and an adaptive visualization method to obtain effective visualization results efficiently. |
| Maintenance and calibration for the light scattering airborne particle counter |
| The appropriate maintenance of the measurement instruments is required to ensure the performance of the measurement instrument and the reliability of the measurement results. Generally, it is required for regular maintenance and calibration. But, for a particle counter, the relation between the measurement results and the calibration results can not be treated the same as a general measurement instrument. Therefore it is explained about the standards and calibration items relating to the performance of particle counter, and about the calibration method for the measurement of particle concentration and particle size in particular. And it is described the differences from maintenance and calibration in the general measurement instrument. |
vol.50-6(2013/3/31)
| Research on the “Task and Ambient” Air Cleaning System − Efficient treatment method of the high temperature heat from equipment − |
| In the cleanroom, since a high-heat-generation equipment is installed, in order to realize energy saving, it is important to process the generated heat efficiently. In this paper, the “Efficient treatment method of the high temperature heat from equipment” outline, the temperature distribution characteristic, the cleanliness characteristic, and the energy-saving performance are reported. As a result, it was clarified that the energy consumtion of this system is 10-20% smaller than that of the conventional T&A air-cleaning system and the air cleaning performances of this system are as same as that of the conventional T&A air-cleaning system. |
| Behavior of adsorption of airborne nanoparticle on wafer |
| With the shrinking of device size, strict control of airborne particles has been required. Previous studies have concluded that semiconductor cleanrooms contain negligible amounts of nanoparticles. A nanoparticle is a particle whose diameter is 100 nm or less. Several examples of nanoparticle measurement are shown in this report. Behavior of airborne particles is analyzed and their deposition velocity is experimentally obtained. It is confirmed that the measured velocity agrees with the theoretical value and the nanoparticles are found to have a higher rate of adsorption than above 100 nm particles. The results of investigation indicate that an ionizer is one of the origins of the nanoparticles. |
| Study on Improvement in Sensitivity of a QCM Surface-Modification-Type Sensor for Clean Rooms |
| The use of on-site real-time monitoring techniques for gaseous contaminants in clean rooms has been required to control the yield value of products and maintain a performance of chemical filters, etc. Especially, the use of Quartz Crystal Microbalance (QCM) sensors recently has been studied. We reported the effectiveness of surface modification of the QCM sensor electrode and controlling the air feed conditions of the sensor surface in order to improve the sensitivity. In this report, with the goal of improving the much higher sensitivity, we modified the surface of a QCM sensor electrode by depositing silicon on the electrodes and its etching to increase the surface area. Besides, examinations were conducted to find the optimum air-feed conditions (feed angle and velocity) of the sensor surface. The results show that the silicon membrane etching is important to increase the surface that contaminants can adhere to, which is an effective method of improving sensitivity. The micro structure of line & space or dots pattern can influence the adhesion of air onto the sensor electrode and accelerate the adsorption of contaminants. The most effective method for feeding air to the sensor electrode was at 45-90 feed angles to both surfaces of the sensor at a rate of 0.6 L/min-0.9 L/min. |
| Sensitive evaluation of airborne anion contaminants with short-time sampling using the solid phase sampler |
| The impinger method, the collection of ionic compounds into liquid, has been widely used for the evaluation of acid and base compounds in the cleanroom environment so far. But this method has some inconveniences, one is to need long sampling time, usually 24 hours, to achieve higher sensitivity, the other is the transportation of the apparatus by air. So we have developed the new solid phase adsorbent active sampler to solve these problems. We reported the evaluation method of sulfate ion(SO42−) and chloride ion(Cl-) using solid phase adsorbent active sampler(BremS(R)-A) for acid compounds in the previous conference 2). In this report, we examined the validity to other acid compounds such as fluoride(F-), bromide(Br-), iodide(I-), acetic acid(CH3COOH), formic acid(HCOOH) and nitrate ion(NO3-) in air using BremS(R)-A. Analytical results between BremS(R)-A and impinger method in air showed a good correlation, so BremS(R)-A is useful and convenient for the evaluation of these acids concentration in air. |
| A consideration on analytical method of styrene in indoor air by using charcoal tube collection / carbon disulfide extraction / GC-MS method |
| There are solid collection/thermal desorption/GC-MS method, solid collection/solvent extraction /GC-MS method and canister method in the analytical method of styrene in indoor air. It is widely used as a method that the analytical procedure is simple on charcoal tube collection and carbon disulfide extraction/GC-MS method in they analytical method and is cheap. However, the styrene which exists in the indoor environment, since recovery of styrene is low, has been underestimated, when this method was applied to the measurement of styrene in the general environment, and there is it. Then, recovery correction method which added styrene-d8(surrogate) ) was examined in this study. This method is sampling method, after styrene- d8 is beforehand added to the charcoal tube sampler. After the sampling, scavenger is transferred to the stoppered test tube, and it added this internal standard toluene-d8. In addition, styrene is extracted by adding carbon disulfide. The compensation of styrene is carried out from the recovery of surrogate. The measurement was carried out on known styrene gas using this method and it was compared with the theoretical value. As the result, theoretical value and analysis value agreed within ±3 %. |
| Analysis of Ions Generated by Corona Discharge Ionizer in Indoor Environment |
| Mass spectrometric measurements of ions generated by a corona discharge ionizer in indoor environment were conducted using an atmospheric pressure ionization mass spectrometer. In the obtained mass spectra, CO3− ions predominated and the conversions from CO3− to the ions of NO3− and HCO3− were observed. The ion composition in the mass spectra was strongly influenced by H2O concentration. With decreasing H2O concentration, the ion evolution to CO3− as well as that from CO3− to other ion species proceeded slowly. When the relative humidity was very low, O2− was the major ion species in the mass spectra instead of CO3− and was observed to persist for long in indoor air. The formations of O3, NOx, and OH radicals by corona discharge, which vary depending on indoor condition such as water vapor concentration, influence the negative ion chemistry in indoor air. |
| A suggestion on new air cleaning device using with chemical additive agent and air freshener |
| The air cleaning technology that achieves the high removal performance, the long-term durability of removal performance and the system that regularly monitors indoor air quality are demanded. Therefore, we developed the high performance room air cleaner with multi-function system which satisfies these demands. In addition to the high removal performance and the long-term durability of removal performance, this new room air cleaner has various diagnostic functions and the network ones. The present study reports the feature of this new room air cleaner and its chemical substance removal performance. |
| Calibration standards for number concentration measurement of airborne and liquid-borne particles |
| Metrological standards for calibration of number concentration of airborne and liquid-borne particles developed at the National Institute of Advanced Industrial Science and Technology (AIST) are described in this article. For airborne (i.e., aerosol) particles. AIST has been providing a calibration service for instruments that measure particle number concentration since 2008. In this service, the primary standard of AIST, which consists of a Faraday-cup aerosol electrometer and an aerosol generator that is capable of generating singly-charged, size-classified particles, is used. Another standard for airborne particles is an aerosol generator that utilizes the inkjet technique for generation of particles at a known rate. These standards are intended to provide means of quality assurance for airborne particle measurements by condensation particle counters (CPCs) and optical particle counters (OPCs). For liquid-borne particles, AIST has been providing a calibration service that evaluates particle number concentration of reference materials that contain mono-dispersed particles and pure water. The particle number concentration is determined by evaluation of the total particle number in a sampled liquid with a flow cytometer, which was modified by AIST, following measurement of the mass of the sampled liquid. Future directions in expanding these airborne and liquid-borne standards are discussed. |
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Air Cleaning Association