Indoor Air Quality Test Research Articles

Liquid crystal gel-based acetone sensor using correlated laser speckles

Acetone, a common volatile organic compound (VOC), poses health risks even at low concentrations. Current acetone sensors are costly and require specialized equipment and expertise. This work develops a novel vapor sensor for determining acetone vapor concentration using the speckle patterns generated by liquid crystal gels (LCGs). The vapor sensor comprises a LCG film prepared by the phase separation of a mixture containing polystyrene microspheres and liquid crystals (LCs). The orientation of the LC molecules changes when the LCG film is exposed to an acetone vapor environment, altering the equivalent refractive indices of the LC domains. This leads to a change in the scattering state of the LCG film under laser illumination, forming different speckle patterns. The concentration of acetone vapor is determined by calculating the correlation coefficient of the speckle images, where the sensitivity and limit of detection of the sensor are 4×10-4 ppm-1 and 754.05 ppm, respectively. The developed correlated laser speckle-based optical system is simpler, less expensive, and more stable than traditional LC film vapor sensors. This acetone gas sensor has potential applications in industrial and indoor air quality testing.

Design and Construction of Enzyme-Based Electrochemical Gas Sensors.

The demand for the ubiquitous detection of gases in complex environments is driving the design of highly specific gas sensors for the development of the Internet of Things, such as indoor air quality testing, human exhaled disease detection, monitoring gas emissions, etc. The interaction between analytes and bioreceptors can described as a "lock-and-key", in which the specific catalysis between enzymes and gas molecules provides a new paradigm for the construction of high-sensitivity and -specificity gas sensors. The electrochemical method has been widely used in gas detection and in the design and construction of enzyme-based electrochemical gas sensors, in which the specificity of an enzyme to a substrate is determined by a specific functional domain or recognition interface, which is the active site of the enzyme that can specifically catalyze the gas reaction, and the electrode-solution interface, where the chemical reaction occurs, respectively. As a result, the engineering design of the enzyme electrode interface is crucial in the process of designing and constructing enzyme-based electrochemical gas sensors. In this review, we summarize the design of enzyme-based electrochemical gas sensors. We particularly focus on the main concepts of enzyme electrodes and the selection and design of materials, as well as the immobilization of enzymes and construction methods. Furthermore, we discuss the fundamental factors that affect electron transfer at the enzyme electrode interface for electrochemical gas sensors and the challenges and opportunities related to the design and construction of these sensors.

Analysis and Study of credits for IGBC Green New Building

The green building movement in India has gained significant momentum with over 8,669 registered projects under the Indian Green Building Council. The LEED standards influence the design and construction of environmentally sustainable structures with a focus on resource conservation, waste reduction, and creating healthy spaces. The IGBC criteria encompasses aspects such as sustainable architecture and design, site selection, energy and water conservation, building materials, indoor environmental quality, and innovation. Energy efficiency and water conservation are emphasized through eco-friendly refrigerants, renewable energy sources, and water-wise practices. The use of certified green building materials, products, and equipment helps reduce environmental impact. Indoor environmental quality is maintained through adequate ventilation, low-emitting materials, and indoor air quality testing. Building owners and contractors can employ various strategies to improve the well-being of occupants. Key Words: Green building, Sustainable, Conservation, Environment, Eco-friendly, Renewable

Air Qualities in School Classrooms by On-site Direct-reading Measurement and Korean Standard Method for Indoor Air Quality Test

Air Qualities in School Classrooms by On-site Direct-reading Measurement and Korean Standard Method for Indoor Air Quality Test

Uncertainty evaluation for nine VOC gas certified reference materials used for indoor air testing

9 kinds of volatile organic compounds (VOC) gas certified reference materials (CRM) for indoor air quality testing were developed at nominal 1 µmol/mol in nitrogen. The property value was assigned gravimetrically and its uncertainty was evaluated by combining different contributions to uncertainty. The resources of uncertainty were discerned as the preparation process, homogeneity and stability and the evaluation method of each uncertainty component was proposed, especially the uncertainty calculation method of raw material’s purity encountered with “interference impurity” was discussed. The relative expanded uncertainties (k = 2) of the nine VOC CRM were in the range from 1.63 % to 2.32 %. The experimental results show: (1) the uncertainty component has basically the similar contribution to the gross uncertainty of its property value; (2) the uncertainty associated with the mass weighing of nine VOC mixed intermediate liquid has the greatest influence on the uncertainty caused by the preparation process; (3) the nine VOC CRM was stable for minimum 12 month with pressure above 2 MPa but their uncertainties should be assessed and combined; (4) more attention should be attached to the uncertainly connected with stability to study its long-time stability.

An Investigation of Indoor Air Quality in a Recently Refurbished Educational Building

Young people spend extended periods of time in educational buildings, yet relatively little is known about the air quality in such spaces, or the long-term risks which contaminant exposure places on their health and development. Although standards exist in many countries in relation to indoor air quality in educational buildings, they are rarely subject to detailed post-occupancy evaluation. In this study a novel indoor air quality testing methodology is proposed and demonstrated in the context of assessing the post-occupancy performance of a recently refurbished architecture studio building at Loughborough University, United Kingdom. The approach used provides a monitoring process that was designed to evaluate air quality in accordance with United Kingdom national guidelines (Building Bulletin 101) and international (WELL Building) standards. Additional, scenario-based, testing was incorporated to isolate the presence and source of harmful volatile organic compounds, which were measured using diffusive sampling methods involving analysis by thermal desorption - gas chromatography - mass spectrometry techniques. The findings show that whilst the case-study building appears to perform well in respect to existing national and international standards, these guidelines only assess average CO2 concentrations and total volatile organic compound limits. The results indicate that existing standards, designed to protect the health and wellbeing of students, are likely to be masking potentially serious indoor air quality problems. The presence of numerous harmful VOCs found in this study indicates that an urgent revaluation of educational building procurement and air quality monitoring guidelines is needed.

Indoor air quality test and air distribution CFD simulation in hospital consulting room

Abstract Reasonable air distribution is crucial to improve the air quality in hospital consulting room. Different air distribution schemes have certain effects on indoor temperature field, air flow field and particle concentration field. Based on a large general hospital project, this paper makes a subjective questionnaire survey and field test on indoor air quality of hospital buildings. Field test parameters include temperature, indoor air velocity, humidity, carbon dioxide and total volatile organic compound concentration. The results of the questionnaire survey show that a small number of people are not satisfied with the air quality in the hospital consulting room, and the concentration of carbon dioxide in some areas is high, which affects human health. The geometric model is established according to the test data, and the numerical simulation is carried out by CFD software to study the effects of three different air distribution. The research results show that the air distribution form of up-supply and side-return is more suitable for hospital consulting room and the air quality is better.

Performance of Calcium Chloride and Silica Gel as Solid Desiccant Dehumidifiers for Indoor Air Quality

Desiccant materials are recently discovered as a viable alternative in dehumidification technology due to their naturally hygroscopic qualities and minimal energy requirement. This paper discusses the performance of four brand samples of selected desiccants used for dehumidification. In this study, dehumidification ability and indoor air quality (IAQ) tests were carried out. The dehumidification ability test was conducted in a controlled environmental chamber at a temperature of 25°C, relative humidity of 70%, and air velocity of 2 m/s for 45-minute session. Meanwhile, the IAQ test was carried out in a naturally ventilated test room, and six IAQ parameters (relative humidity, air velocity, air temperature, particulate matter (PM10), airborne bacteria and carbon dioxide (CO2) were studied. The IAQ test was performed for five different conditions: control, application of brand samples A, B, C and D in the test room. From this study, it was found, brand A (0.6823 g/kg) and brand B (0.6849 g/kg) had a relatively good dehumidification ability during the 45-minute dehumidification ability test compared to brand C (0.3108 g/kg) and brand D (0.3982 g/kg). The IAQ test revealed that brand A had the biggest variation in indoor-outdoor relative humidity of 13.12%, while brand D had the smallest difference of 11.83%. Brand B had the highest average PM10 concentration of 0.037 μg/m3. The airborne bacterial count for all conditions had no statistical significance, indicating the application of desiccants were not effective in reducing airborne bacteria. From this study, it can be concluded that calcium chloride (brand A and B) samples performed better than silica gel (brand C and D) samples in terms of dehumidification ability and IAQ profile.

Indoor Air Quality of Historic Buildings: A Comparison of Certified to Non-certified Buildings

Since, there is a high level of concern for historic buildings becoming sustainable this paper will investigate the indoor air quality of three historical buildings that are on the National Registry of Historic Buildings and located around Fulton County, Georgia, USA and three historical buildings that are not certified in the same area. The certification for the three certified buildings was obtained thru Earth Craft Sustainable Preservation program, which is the only historic building certification in the United States. The research entails field measurements of CO₂ levels, air borne particles (both types and sizes), and greenhouse gas emissions. This was done by counting the airborne particles with sizes between 0.3 to 5.0 nanometers, and identifying biological and non-biological airborne particles both indoors and outdoors. These tests were used to determine if the interior of the certified buildings have better CO₂ levels than the exterior and to ascertain how much the certification process effects the indoor air quality. This information will be compared to the noncertified buildings to ascertain if the results of the testing will show that the indoor air quality and greenhouse gases are better than the noncertified buildings. This research will demonstrate the need for improved indoor air quality testing in historic buildings before certifying them as being sustainable in the area of indoor air quality.

제주국제공항 여객터미널의 실내 미세먼지 분석에 관한 연구

This study was conducted to analyse indoor air quality of the Juju International Airport such as fine dust. Density of fine dust, one of major component to figure out a indoor air quality, was measured from 2014 to 2018. The test was performed based on maintenance standards and recommended standards for air quality in the regulation on the “Regulation of Indoor Air Quality” and “Standard for Indoor Air Quality Test” from the Institute of National Environment Science. The test was performed every quarterly of the year based on the “Airport Environment Condition Standards” of the notification from the Ministry of Land, Infrastructure and Transport. As results, the PM-10 and PM-2.5 particles are measured and it is found out that the indoor air quality in the passenger terminal of the Jeju International Airport is controled less than the standard level of the Indoor Air Quality Control Law of the government.

The evaluation of homogeneity and stability of proficiency testing materials in indoor air quality test

The evaluation of homogeneity and stability of proficiency testing materials in indoor air quality test

Analysis of hospital interior air quality audits

In general, people spent more than 80∼90% of living time in the indoor every day, human health and indoor environmental quality are closely related. The hospital has a complex and unique environmental characteristics, medical personnel and patients are prolonged exposed to risk factors in a variety of environments. Therefore, the merits of indoor air quality in the hospital, not only has a threat to the health of medical personnel and patients, but also will directly affect the quality and efficiency of health care work. A regular monitoring can, improve and maintain a well of indoor air quality, thus ensuring the safety maintenance of medical personnel and patients in hospital, it has become an important issue for hospital. This study has literatures review to collate and analyse that are related issues with indoor air quality. Then measures the indoor air quality test with direct-reading instruments. In selected hospital of this study were field-tested, then use the measured data in the field, discussion and analysis of the causes of air pollutants and the establishment of the sensing area of pollutants Concentration empirical mode.

실내공기질 공정시험법 중 VOCs 측정방법의 문제점 고찰 및 개선방안에 관한 연구

During the last two decades, indoor air quality and volatile organic compounds (VOCs) have been of concern in Korean society due to their nature of potential health impacts. In order to investigate the pollution levels of VOCss in indoor environments, establishment of a solid test method for monitoring the airborne VOCss is essential. In Korea, a method based on adsorbent sampling and GC analysis coupled with thermal desorption was proclaimed as the Korea Standard Method for Indoor Air Quality Test. This study was carried out to examine some inherent problems of the VOCs measurement method. The VOCs method does not describe in detail preparing the standard samples. The standard samples may be prepared by impregnation of either liquid standard solutions or a mixture of standard gases. In this study, we investigated the optimal temperature condition for transferring the liquid standards onto a standard adsorbent tube. As a result, keeping the impregnation temperature at 250℃ will be recommended in regard of the boiling points of multiple target analytes and the thermal stability of the adsorbent. We also demonstrated some problems associated with handling of a syringe used for transferring the standard solutions onto the adsorbent tubes, and a best way to get rid of the syringe problems was suggested. Finally, a number of field works were conducted to evaluate the performance of adsorbent sampling methods. Comparison of different adsorbent tubes, i.e. tube packed with single sorbent (Tenax) and double sorbents (Tenax with Carbotrap), revealed that 30 to 40% differences between the two groups, implying that sampling efficiency is depending on the volatility and the strength of adsorbents. However, duplicate precisions for VOCs sampling with a same type of adsorbent and at same flow rates appeared to be satisfactory to be all within 20%, which is a quality control guideline. Distributed volume precisions were also found to be within a guideline value, 25%, although the precision was in general inferior to the duplicate precision. The Korea indoor VOCs test method should be more refined and improved in many aspects, particularly procedure and instrumentation for preparing the standard samples and specification of quality control assessment.

Indoor Air Quality Testing in Low-Energy Wooden Houses: Measurement of Formaldehyde and VOC-s

The objective of our study is to determine the indoor air quality of a low-energy wooden house. During the field measurements we detected the presence of formaldehyde (34 µg/m 3 ), BTX (35.51 µg/m 3 ), and some materials in the terpene family, limonene (64.7 µg/m 3 ), and alpha-pinene (297 µg/m 3 ), in the indoor air. The concentration of the detected TVOC (Total Volatile Organic Compounds) was 2150 µg/m 3 , which does not significantly differ from European average values. The LCI (Lowest Concentration of Interest) analysis shows that none of the VOCs tested by us are a health risk to the occupants in the building. However, it can be established that the health risk of benzene (0.622) stands out from the tested substances. The health risks of other aliphatic hydrocarbons (0.176) and alpha- pinene (0.198) may be considered identical, but even these do not pose a risk to humans. In order to clarify the sources of the harmful substances further investigations are needed.

Forensic Engineering Investigation Of Moisture Intrusion Leading To Mold Conditions

While Moisture Intrusion Was Thought To Be The Reason For Floor Tile And Carpet Adhesion Failure In An Occupied Elementary School, The Flooring Problems Were Symptoms Of Only Some Of The Many Moisture Problems That Were Discovered. By Using Destructive And Non-Destructive Testing Methods, A List Of More Than A Dozen Construction Deficiencies Was Compiled. Since The School Was In Session, The Parent-Teacher Organization Was Kept Informed Of The Indoor Air Quality In The School. Indoor Air Quality Testing Was Performed At Strategic Intervals Of The Project And A Final Indoor Air Quality (Iaq) Test Was Performed At The Completion Of The Work As A Baseline For Recommended Future Testing.

Evaluation of the Filtration Performance of Biocide Loaded Filter Media

This paper presents the results of a study designed to evaluate the filtration performance of nonwoven filtration media which have been loaded with a variety of biocides for use as potential indoor air filters. A test stand was constructed based on a modification of the ASTM 1215 Standard to provide testing of the bacterial removal efficiency of the filtration media. Biocide-loaded filtration media were first tested on an ASTM 1215 test stand using standard monodispersed latex spheres to determine the particle removal efficiency as a function of particle sizes in the 0.5 to 2.0 micrometer sizes. A multichannel optical particle counter was used to assess the efficiency. Additional samples of the same media were then tested in the modified ASTM 1215 test stand, referred to as the Biocontaminant Indoor Air Quality Test Stand (BIAQTS) by atomizing bacteria (Gram positive and Gram negative) and fungi into the test stand. Initial bacterial testing was conducted using single-stage microbial samplers to determine the efficiency of filters for removing Escherichia coli (E. coli) bacteria and other bacteria. In addition to testing the filtration efficiency, additional tests were conducted on samples of the filter by placing small disk samples of the unexposed biocide-loaded filters and a non-loaded control filter onto microorganism-loaded agar in petri dishes. Microorganisms studied included four bacteria, a fungus, and an opportunistic pathogen. The samples were then incubated and quantitative analyses were conducted to determine the zone of inhibited growth of the microorganisms around the disks due to the biocide treatments which were applied to the filters. The results are presented for two of a series of biocide-loaded nonwoven filters which were prepared using two different techniques for loading the biocides: 1) nonwoven filters which were prepared by mixing the biocide with the polypropylene polymer prior to meltblowing the polymer into a filter - referred to as impregnated biocide, and 2) spray application of the biocides as a finish onto the filter media–referred to as post treatment. The effects of impregnated versus post treatment applications on filtration efficiency and on the inhibition of bacterial growth on the filters are presented.

Predicting the emissions of individual VOCs from petroleum-based indoor coatings

The indoor use of petroleum-based coating materials may cause elevated volatile organic compound (VOC) concentrations. This paper presents a newly developed mass transfer model for estimating the emissions of individual VOCs from freshly coated surfaces. Results of a four-step validation show that the predicted individual VOC emissions are in good agreement with experimental data generated in small chambers and an indoor air quality test house. The values of the parameters introduced in this model are all easily obtained, and thus its utilization can provide indoor air quality professionals with emission rate estimates for individual VOCs without having to conduct costly dynamic chamber testing.

Gas-Phase Mass Transfer Model for Predicting Volatile Organic Compound (VOC) Emission Rates from Indoor Pollutant Sources

Abstract Analysis of the impact of sources on indoor pollutant concentrations and occupant exposure to indoor pollutants requires knowledge of the emission rates from the sources. Emission rates are often determined by chamber testing and the data from the chamber test are fitted to an empirical model. While the empirical models are useful, they do not provide information necessary to scale the chamber data to buildings nor do they provide information necessary to understand the processes controlling emissions. A mass transfer model for gas-phase-limited mass transfer is developed and described in this paper. Examples of sources with gas-phase-limited emissions are moth cakes, floor wax, stain, and varnish. The mass transfer model expresses the emission rate in terms of a mass transfer coefficient and a driving force. The mass transfer coefficient can be predicted from correlations of the Nusselt number and the Reynolds number. The experiments and data analysis used to develop the correlation are described in the paper. Experiments to verify the assumptions used to describe the driving force are also described. Suggestions for using data from existing empirical emission models to determine parameters for the mass transfer model are provided. The mass transfer model provides a significantly better fit to data from an indoor air quality test house than does the empirical first order decay model.