Добірка наукової літератури з теми "Analyzer for total volatile organic compounds (TVOC)"

The article analyzes the impact of measured concentrations of Total Volatile Organic Compounds (TVOC) emissions determined for four BREEAM certified buildings on the Indoor Air Quality Index (IAQindex) and the overall Indoor Environment Quality index (IEQindex). The IEQindex indicates the percentage of building users who are satisfied from the indoor environment. In existing IEQ models, currently the concentration of CO2 is mostly used to evaluate the IAQindex sub-component. Authors point out that it is recommended to use TVOC instead CO2 at pre-occupant stage where building is mainly polluted by emission from finishing products. The research provides the approach where the component related to the emission of TVOCs is implemented to IEQ model. The first stage of assessment was a test of the volatile organic compounds concentrations in case study buildings. Secondly, the analysis results were assigned into the number of dissatisfied users (PD(IAQ)) from the theoretical function given by Jokl-Fanger resulting from the Weber-Fechner equation. Finally, the overall IEQindex was calculated. The IEQ approach proposed in this paper is mainly based on a consideration of EN 15251 and scientifically accepted models.

The qualitative and quantitative composition of volatile organic compounds (VOC) emitted from furnishings from solid wood and all kinds of wood derivative materials depends on many factors, of which the most important is the wood species. The intraspecies and interspecies differences in VOC emission result from the differences in the chemical composition and anatomical structure of heartwood and sapwood of different species. VOC composition analysis was performed separately for heartwood and sapwood of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) Karst.) and European larch (Larix decidua Mill.) trees. The studies were conducted in a glass climatic chamber of 0.025 m3, equipped with a system for the monitoring and control of climatic conditions. Samples of air for analyses were collected after 3, 7, 14 and 28 days of exposure. The results provided evidence for interspecies and intraspecies differences in the qualitative and quantitative compositions of VOC. The concentration of total VOC (TVOC) released from heartwood of Scots pine was higher than that released from sapwood. For European larch and Norway spruce, the opposite relations were observed. The VOC emission from Scots pine heartwood was about 17 times higher than the emission from European larch and Norway spruce heartwood. The differences in TVOC emitted from the sapwood of samples from different species were smaller. For each of the species, the highest percentage contribution to TVOC was made by terpenes. The second highest percentage contribution in TVOC was made by compounds containing a carbonyl group, mainly aldehydes, while aromatic compounds made the third highest contribution.

The high relative humidity of the air and many potential growth media, such as bedding materials, hay and grains in the horse stable, for example, provide suitable conditions for fungal growth. Metabolic activity of four common agricultural fungi incubated in peat and wood shavings at 25°C and 4°C was characterized in this study using previously specified volatile metabolites of micro-organisms and CO2 production as indicators. The volatile organic compounds were collected into Tenax resin and analysed by gas chromatography. Several microbial volatile organic compounds (MVOCs), e.g. 1-butanol, 2-hexanone, 2-heptanone, 3-octanone, 1-octen-3-ol and 1-octanol were detected in laboratory experiments; however, these accounted for only 0.08-1.5% of total volatile organic compounds (TVOCs). Emission rates of MVOCs were 0,001-0.176 μg/kg of bedding materials per hour. Despite some limitations of the analytical method, certain individual MVOCs, 2-hexanone, 2-heptanone and 3-octanone, were also detected in concentrations of less than 4.6 μg/m3 (0.07-0.31% of TVOC) in a horse stable where peat and shavings were used as bedding materials. MVOC emission rate was estimated to be 0.2-2.0 μg/kg x h-1 from bedding materials in the stable, being about ten times higher than the rates found in the laboratory experiments. Some compounds, e.g. 3-octanone and 1-octen-3-ol, can be assumed to originate mainly from microbial metabolisms.

Abstract. Measurements of temporal and spatial changes to indoor contaminant concentrations are vital to understanding pollution characteristics. Whilst scientific instruments provide high temporal resolution of indoor pollutants, their cost and complexity make them unfeasible for large-scale projects. Low-cost monitors offer an opportunity to collect high-density temporal and spatial data in a broader range of households. This paper presents a user study to assess the precision, accuracy, and usability of a low-cost indoor air quality monitor in a residential environment to collect data about the indoor pollution. Temperature, relative humidity, total volatile organic compounds (tVOC), carbon dioxide (CO2) equivalents, and fine particulate matter (PM2.5) data were measured with five low-cost (“Foobot”) monitors and were compared with data from other monitors reported to be scientifically validated. The study found a significant agreement between the instruments with regard to temperature, relative humidity, total volatile organic compounds, and fine particulate matter data. Foobot CO2 equivalent was found to provide misleading CO2 levels as indicators of ventilation. Calibration equations were derived for tVOC, CO2, and PM2.5 to improve sensors' accuracy. The data were analysed based on the percentage of time pollutant levels that exceeded WHO thresholds. The performance of low-cost monitors to measure total volatile organic compounds and particulate matter 2.5 µm has not been properly addressed. The findings suggest that Foobot is sufficiently accurate for identifying high pollutant exposures with potential health risks and for providing data at high granularity and good potential for user or scientific applications due to remote data retrieval. It may also be well suited to remote and larger-scale studies in quantifying exposure to pollutants.

Vehicular emission is a major environmental health problem in the world today especially in developing countries including Nigeria. This study was centered on assessing the vehicular emissions pollutants such as Carbon monoxide (CO), Hydrogen Sulphide (H2S), Formaldehyde (HCHO) and Total Volatile Organic Compound (TVOC) in Benin City, Edo State, Nigeria. The sampling of the CO and H2S gaseous pollutants was done using H-4S gas analyzer while JCG60 gas detector was used to measure TVOC and HCHO. The meteorological parameters were measured with HTC-1 hygrometer thermometer. AQI was calculated to determine the status of the ambient air quality of the study areas. Carbon monoxide concentration obtained from the result ranges from 3.12-16.1 ppm with location C having the highest amount of 16.1 ppm which exceeds the Federal Environmental Protection Agency (FEPA) standard of 10 ppm. The calculated AQI shows that the study areas are all polluted. Continuous measurement and inventory of air pollutants should be encouraged, as this will enable the policymakers to effectively implement control measures on air pollution.

Dubai has the reputation of a continuously growing city, with skyscrapers and mega residential projects. Many new residential projects with poor choices of material and ventilation have led to a faster rise in sick building syndrome (SBS) in Dubai than in any other country, and the IAQ (indoor air quality) has become more critical. Volatile organic compounds (VOCs) and formaldehyde (HCHO) affect the health of residents, producing the phenomenon known as SBS (sick building syndrome). It has been reported that wood materials used for furniture and wooden windows and doors are a significant source of indoor air pollution in new houses. This paper aims to identify the factor elements emitting harmful chemical substances, such as VOCs and HCHO, from wooden mashrabiya (traditional Arabic window) by examining the characteristics of the raw and surface materials through test pieces. As a methodology, a small chamber system was used to test the amount of hazardous chemicals generated for each test piece. For Total volatile organic compounds (TVOC) and HCHO, the blank concentration before the injection and the generation after seven days were measured. The results showed that to reduce TVOC, it is necessary to secure six months or more as a retention period for raw materials and surface materials. The longer the retention period, the smaller the TVOC emission amount. In the case of mashrabiya, an HCHO low-emitting adhesive and maintenance for one month or more are essential influencing factors. It was proven that using raw materials with a three-month or more retention period and surface materials with a one-month or more retention period is safe for indoor mashrabiya. This study is the first study in the Middle East to identify factors and characteristics that affect the emission of hazardous chemicals from wood composite materials, such as wood mashrabiya, that affect indoor air quality in residential projects in Dubai. It analyzes the correlation between emission levels and the retention period of raw and surface materials, in order to provide a new standard for indoor air pollutants.

The paper investigates the effects on building indoor air quality (IAQ) resulting from the choice of different design ventilation rates. A reference residential building was analysed by means of the multizone modelling software CONTAM, by monitoring the concentration of two pollutants: occupant-generated carbon dioxide (CO2) and total volatile organic compounds (TVOC) from indoor sources. A demand-controlled ventilation strategy based on building occupancy was implemented and users' presence schedules were defined. Specifically, the evolution of indoor pollutant concentrations was investigated when the design ventilation rates, recommended by two IAQ-related standards (the Italian UNI 10339 and the European EN 15251), were implemented through a mechanical ventilation system. Different results regarding the IAQ level were achieved accordingly to the dissimilar ventilation rates. After a statistical analysis on the distributions of CO2 and TVOC concentrations, EN 15251 outcomes showed overall better results of the analysed statistical metrics, i.e. prevalence, sensitivity and accuracy. Indeed, the EN 15251 design airflows led to indoor conditions that were more often classified either in the correct air quality class or in a higher class. Finally, a better alignment between the national and European IAQ standards is recommended, especially in terms of airflows, air quality classes and pollutant limit values.

Sydney Metro is the biggest project of Australia’s public transport, which was designed to provide passengers with more trains and faster services. This project was first implemented in 2017 and is planned to be completed in 2024. As presented, the project is currently in the construction stage located on the ground stations of the Sydney Trains Bankstown line (T3). Based on this stage, several construction activities will generate air pollutants, which will affect the air quality around construction areas. Moreover, it might cause health problems to people around there and also the passengers who usually take the train on the T3 line. However, there is no specific data for air quality inside the train that may be affected by the construction from each area. Therefore, the aim of this study is to investigate the air quality inside the train carriage of all related stations from the T3 line. A sampling campaign was conducted over 3 months to analyze particulate matter (PM) concentration, the main indoor pollutants including formaldehyde (HCHO) and total volatile organic compounds (TVOC). The results of the T3 line were analyzed and compared to Airport & South line (T8) that were not affected by the project’s construction. The results of this study indicate that Sydney Metro construction activities insignificantly affected the air quality inside the train. Average PM2.5 and PM10 inside the train of T3 line in the daytime were slightly higher than in the nighttime. The differences in PM2.5 and PM10 concentrations from these periods were around 6.8 μg/m3 and 12.1 μg/m3, respectively. The PM concentrations inside the train from the T3 line were slightly higher than the T8 line. However, these concentrations were still lower than those recommended by the national air quality standards. For HCHO and TVOC, the average HCHO and TVOC concentrations were less than the recommendation criteria.

Fire alarm systems are typically equipped with various sensors such as heat, smoke, and gas detectors. These provide fire alerts and notifications of emergency exits when a fire has been detected. However, such systems do not give early warning in order to allow appropriate action to be taken when an alarm is first triggered, as the fire may have already caused severe damage. This paper analyzes a new dataset gathered from controlled realistic fire experiments conducted in an indoor laboratory environment. The experiments were conducted in a controlled manner by triggering the source of fire using electrical devices and charcoal on paperboard, cardboard or clothing. Important data such as humidity, temperature, MQ139, Total Volatile Organic Compounds (TVOC) and eCO2 were collected using sensor devices. These datasets will be extremely valuable to researchers in the machine learning and data science communities interested in pursuing novel advanced statistical and machine learning techniques and methods for developing early fire detection systems. The analysis of the collected data demonstrates the possibility of using eCO2 and TVOC reading levels for early detection of smoldering fires. The experimental setup was based on Low-Power Wireless Area Networks (LPWAN), which can be used to reliably deliver fire-related data over long ranges without depending on the status of a cellular or WiFi Network.

Adopting the methods of subjective questionnaire and objective test, the indoor air quality (IAQ) of residential buildings in Lhasa were analyzed in summer and winter, and the results were compared with that in Chongqing. Firstly, the data shows that the overall IAQ in Lhasa is better. Excepted total volatile organic compounds (TVOC), the concentration of formaldehyde, carbon dioxide (CO2), PM2.5 are low. Secondly, more than 80% residents accepted the IAQ in Lhasa, which means the satisfaction rate is high. Thirdly, the IAQ in Lhasa is better than that in Chongqing, such that the exceed-standard rate of formaldehyde is only 2.5% in Lhasa, while 85.7% in Chongqing, and residents’ satisfaction rate in Lhasa is higher. Meanwhile, there are some difference about IAQ in different seasons. The overall concentration of indoor pollutants in summer is lower than that in winter, and residents satisfaction rate on the summer IAQ is higher than winter in Lhasa. Finally, the main effect factors on IAQ were analyzed, and some suggestions to improve the IAQ of residential buildings were provided.

Метою роботи є розробка системи поточного контролю температури, вологості, атмосферного тиску повітря на основі сучасної мікроелектронної компонентної бази, а також моніторингу та аналізу стану забруднення повітря в частині визначення концентрації летючих органічних сполук (TVOC) і еквівалентного рівня діоксиду вуглецю (eCO2). Дипломна робота орієнтована на поглиблене вивчення фізичних методів визначення вмісту найбільших забрудників повітря та передбачає аналіз сучасного стану ринку електронних первинних перетворювачів в названій сфері та контролерів для побудови систем моніторингу та аналізу. В першому розділі дипломної роботи розглянуто нормативну базу в сфері отримання та аналізу інформації про поточний стан атмосферного повітря, проаналізовано відмінності в підходах до індексації якості повітря в Європі та Україні, визначено їх недоліки та переваги. У другому розділі розглянуто методики визначення вмісту основних забрудників повітря та проведено аналіз структурних схем аналізаторів, розглянуто особливості їх ключових конструктивних елементів, проведено порівняння конструкції і архітектури, наведено окремі принципові схеми вимірювання. В третьому розділі розглянуто сучасні типи мікроелектронних первинних перетворювачів фізичних параметрів атмосферного повітря, його хімічного складу та механічних забрудників. Проаналізовано технічні та метрологічні параметри сучасних сенсорних пристроїв з оглядом на відповідність сучасним вимогам, нормам, типам інтерфейсів. За результатами детального вивчення інформації у зазначених областях вибрано мікроелектронні сенсори з цифровим вихідним інтерфейсом для побудови мікроконтролерних системи моніторингу: - сенсор температури, вологості та атмосферного тиску BME 280; - мікромеханічний сенсор абсолютного тиску моделі BMP180 (висоти над рівнем моря) з роздільною здатністю 6 кПа ( відповідає роздільній здатності за зміною висоти 0.5 м) в режимі ультра-низького споживання та 2 hPa кПа ( відповідає зміні висоти 0.17 м) в режимі прецизійного вимірювання; - сенсор комплексного визначення якості повітря Adafruit CCS811 з можливістю визначення рівня летючих органічних сполук та ефективного рівня СО2 (CCS811 - Adafruit CCS811 Air Quality Sensor Breakout - VOC and eCO2) з додатковим вбудованим блоком прецизійного сенсора температури і вологості HDC1080. Для проектування системи моніторингу використано контролер ARDUINO UNO. В роботі запропоновано структурну схему системи і наведено схему підключення кожного з компонентів. Також у третьому розділі розроблено програмний код у програмному середовищі Arduino IDE для підключення окремих компонентів системи моніторингу до мікроконтролера, проведено його налаштування.
The work aim is an air quality system development for temperature, humidity, atmospheric pressure monitoring based on modern microelectronic components, as well as for monitoring and analysis of air pollution in terms of volatile organic compounds (TVOC) and equivalent levels of carbon dioxide and other pollutant gases concentration determination. Thesis is focused on in-depth study of physical methods for determining the the largest air pollutants content, on the electronic sensors current state analysis in this area and controllers choice for monitoring and analysis systems design. The first section of the thesis considers the regulatory framework in the field of obtaining and analyzing information about the atmospheric air current state, analyzes the differences in approaches to air quality indexing in the both Europe and Ukraine, identifies their disadvantages and advantages. The second section considers the methods of the major air pollutants content determining and analyzes the structural schemes of analyzers, considers the features of their key structural elements, compares the design and architecture, provides some basic electronic circuits. The third section considers modern types of atmospheric air physical parameters microelectronic sensors, its chemical composition and mechanical pollutants. The modern sensor technical and metrological parameters are analyzed with regard to compliance with modern requirements, norms, types of interfaces. Based on the results of a detailed study of information in these areas, modern microelectronic sensors with a digital output interface were selected to build microcontroller monitoring systems: - BME280 temperature, humidity and atmospheric pressure sensor; - micromechanical absolute pressure sensor model BMP180 (altitude) with a resolution of 6 kPa (corresponds to a change in altitude 0.5m) in the ultra-low consumption mode and 2 hPa kPa (corresponds to a change in altitude 0.17m) in the mode of precision measurement; - Adafruit CCS811 integrated air quality sensor with the ability to determine the level of volatile organic compounds and effective CO2 level (CCS811 - Adafruit CCS811 Air Quality Sensor Breakout - VOC and eCO2) with an additional built-in unit of precision temperature and humidity sensor HDC1080. The ARDUINO UNO controller was used to design the monitoring system. The structural scheme of the system is offered and the scheme of connection of each of components is resulted in the work. Also the program code in the Arduino IDE software environment for separate components of the monitoring system is developed, its adjustment is carried out.

碩士
大仁科技大學
環境管理研究所
102
In recent years, more emphasis has been put on environmental protection and the promotion of health awareness. Many investigations of air pollution and the impact of the air pollution concentrations on human health have gradually received extensive discussions. In order to understand the impacts of total volatile organic compounds (hereinafter referred to as TVOC) in the industrial area on its neighboring schools and residences, this study selects four sites in the industrial area in the south and its neighboring elementary schools and residences. The climate in winter is relatively stable in southern Taiwan. In order to avoid students at schools and factories in operation, this study uses a portable instrument ppbRAE3000 to obtain samples on the air quality only from Monday to Friday during the winter vacation. The detections of air quality are conducted on each site for three time a day (7:00am-8:00am; 10:00am-11:00am; 15:00pm-16:00pm). The results show that the average concentrations of the TVOC (measured in ppb) in the industrial area, Elementary School A, Elementary School B, Elementary School C, Residence 1, and Residence 2 as follows. In the morning (1523.29 ± 933.38,863.47 ± 62.82,488.18 ± 16.84 , 424.85 ± 31.05,831.29 ± 183.158,725.79 ± 285.65); at noon (1035.52 ± 1281.91,484.64 ± 32.15,462.92 ± 15.18,266.70 ± 14.28,711.89 ± 189.64,515.03 ± 58.91); in the afternoon (733.22 ± 344.77,410.56 ± 17.05 , 496.12 ± 56.06,268.48 ± 22.75,355.61 ± 20.84,412.27 ± 40.97). The measured data show that, except for Elementary School B that is heavily influenced by the Taiwan Provincial Highway No. 1, the TVOC concentrations on other sites are highest in the morning, second highest at noon, and lowest in the afternoon. Elementary School C which is most distant away from the industrial area has the lowest TVOC concentrations. Residence 2 which is most distant away from the industrial area has TVOC concentrations lower than Residence 1 has. The results show that the distance from the industrial area is main factor that influences the TVOC concentrations in the air. Therefore, we suggest that some TVOC detection stations be built in the industrial area in the south and that the evacuation routes be planned for school children when the TVOC is detected to exceed normal ranges of concentrations.