Development of a novel methodology for indoor emission source identification (original) (raw)
Related papers
2019
Phthalates are ubiquitous indoor organic pollutants that are found in different building and consumer materials and are known to cause severe human health problems. In this paper, the emission of these compounds from vinyl floorings (VF) into indoor air has been studied using Automated Thermal Desorption-Gas Chromatography-Mass Spectroscopy (ATD-GC-MS) and a special device known as micro-chamber or thermal extractor (µ-CTE TM). So a robust analytical ATD-GC-MS method has been developed and validated to analyse eight selected phthalates. Calibration curves were linear (R 2 > 0.99), limit of detection (LOD) was down to 0.004 µg/m 3 , and the values of relative standard deviation (RSD) were less than 15% for all chosen phthalates. Then, a new micro-chamber measurement method based on diffusion has been developed for studying the emission of Diisononyl phthalate (DiNP) and Din -octyl phthalate (DnOP) from VF at different temperatures and estimating y0 (gas-phase concentration of phthalates on the surface of the material). This method was quite repeatable with 11% RSD for DiNP and 8% for DnOP.
2012
The study objectives were to improve the understanding of the long-term variation of VOC emission chromatograms of building materials and to develop a method to account for this variation in the identification of individual sources of VOC emissions. This is of importance for the application of the source identification method since materials age over time in real indoor environments. The method is based on the mixed air sample measurements containing pollutants from multiple aged materials and the emission signatures of individual new materials determined by PTR-MS. Three emission decay source models were employed and evaluated for their ability to track the change of individual material emission signatures by PTR-MS over a nine-month period. Nine building material specimens were studied in a ventilated 50-L small-size chamber for their emissions individually for nine months, and also in combination later. Chamber exhaust air was sampled by PTR-MS to construct a temporal profile of emission signature unique to individual product type. The similar process was taken to measure mixture emissions from multiple materials, which is for applying and validating the developed method for source identification enhancement, considering the variation in long-term emission rates of individual VOCs. Results showed that the proposed approach could predict the emission signatures of individual building materials at a later time (9-month) with less than 6% difference variance, and hence indicated the potential of the source identification method for aged materials in real indoor environments.
Knowing the value of the key mass-transfer model parameters is a critical requirement for evaluating volatile organic compound (VOC) emissions from indoor materials. The key parameters are diffusion coefficient (D), partition coefficient (K), and initial material-phase emittable concentration (C0). Although these parameters can be individually measured in the laboratory, the required time and expense are substantial. A simple method of determining D and C0 using data from ventilated chamber tests and dimensionless analysis is proposed and then validated using VOC emission data from the material emissions database developed by National Research Council Canada (NRC). The primary application of this method is to provide a rapid screening-level estimate of inhalation exposure to VOCs in building materials. Two standard scenarios using the NRC database are employed to demonstrate the value of the approach to indoor air quality assessment. The method could be a useful screening tool for assessing material emissions or environmental exposures.
Indoor Air, 2010
The objectives of this study were to determine Volatile Organic Compound (VOC) emission signatures of nine typical building materials by using Proton Transfer Reaction-Mass Spectrometry (PTR-MS), and to explore the correlation between the PTR-MS measurements and the measurements of acceptability by human subjects. VOC emissions from each material were measured in a 50-L small-scale chamber. Chamber air was sampled by PTR-MS to determine emission signatures. Sorbent tube sampling and TD-GC/MS analysis were also performed to identify the major VOCs emitted and to compare the resulting data with the PTR-MS emission signatures. The data on the acceptability of air quality assessed by human subjects were obtained from a previous experimental study in which the emissions from the same batch of materials were determined under the same area-specific ventilation rates as in the case of the measurements with PTR-MS. Results show that PTR-MS can be an effective tool for establishing VOC emission signatures of material types, and that there were reasonable correlations between the PTR-MS measurements and the acceptability of air quality for the nine materials tested when the sum of selected major individual VOC odor indices was used to represent the emission level measured by PTR-MS. Keywords Emission signature, PTR-MS, GC/MS, perceived air quality, VOC Practical Implications The study shows that unique emission patterns may exist for different types of building materials. These patterns, or signatures, can be established by using PTR-MS, an on-line monitoring device. The sum of selected major individual VOC odor indices determined by PTR-MS correlates well with the acceptability of air quality assessed by human subjects, and hence provides a feasible approach to assessing perceived indoor air quality. This on-line assessment will open a new gate in understanding the role of VOC emissions from building materials on perceived air quality, forming a good foundation to develop real-time or near real-time methods for standard material emission testing and labeling, quality control of emissions from materials, and assessing the acceptability of air quality in buildings.
Science of The Total Environment, 2016
There is a growing concern regarding the adverse health effects due to indoor air pollution in developing countries including India. Hence, it becomes important to study the causes and sources of indoor air pollutants. This study presents the indoor concentrations of PM 0.6 (particles with aerodynamic diameter less than 0.6 μm) and identifies sources leading to indoor air pollution. Indoor air samples were collected at IIT Kanpur campus. Ninety-eight PM 0.6 samples were collected during November 2013 to September 2014. PM 0.6 concentration was measured using a single stage impactor type PM 0.6 sampler. The average PM 0.6 concentration indoor was about 94.44 μg/m 3. Samples collected were then analysed for metal concentrations using ICP-OES (Inductively Coupled Plasma-Optical Emission Spectrometer). Eight metals Ba, Ca, Cr, Cu, Fe, Mg, Ni and Pb were quantified from PM samples using ICP-OES. Positive Matrix Factorization (PMF) was used for source apportionment of indoor air pollution. PMF is a factor analysis tool which helps in resolving the profile and contribution of the sources from an unknown mixture. Five possible sources of indoor pollutants were identified by factor analysis-(1) Coal combustion (21.8%) (2) Tobacco smoking (9.8%) (3) Wall dust (25.7%) (4) Soil particles (17.5%) (5) Wooden furniture/paper products (25.2%).
Indoor Air, 1993
Polymer materials and thew additives are today ever present in our daily surroundings. llese materials have been found to emit a number of different volatile organic compounds (VOCs) into the ambient air, thus affecting the quality of the indoor air VOCs with detectable concentrations are exchanged between the different materials and indoor aiz Materials present in the system act as sorbents as well as sources of emission, depending on the concentration of the VOCs in the air at a specific time.
A simple method for screening emission sources of carbonyl compounds in indoor air
Journal of Hazardous Materials, 2010
Volatile organic compounds (VOCs) emitted from building and furnishing materials are frequently observed in high concentrations in indoor air. Nondestructive analytical methods that determine the main parameters influencing concentration of the chemical substances are necessary to screen for sources of VOC emissions. Toward this goal, we have developed a new flux sampler, referred to herein as an emission cell for simultaneous multi-sampling (ECSMS), that is used for screening indoor emission sources of VOCs and for determining the emission rates of these sources. Because the ECSMS is based on passive sampling, it can be easily used on-site at a low cost. Among VOCs, low-molecular-weight carbonyl compounds including formaldehyde are frequently detected at high concentrations in indoor environments. In this study, we determined the reliability of the ECSMS for the collection of formaldehyde and other carbonyl compounds emitted from wood-based composites of medium density fiberboards and particleboards. We then used emission rates determined by the ECSMS to predict airborne concentrations of formaldehyde emitted from a bookshelf in a large chamber, and these data were compared to formaldehyde concentrations that were acquired simultaneously by means of an active sampling method. The values obtained from the two methods were quite similar, suggesting that ECSMS measurement is an effective method for screening primary sources influencing indoor concentrations of formaldehyde.
2004
A study to measure indoor concentrations and emission rates of volatile organic compounds (VOCs), including formaldehyde, was conducted in a new, unoccupied manufactured house installed at the National Institute of Standards and Technology (NIST) campus. The house was instrumented to continuously monitor indoor temperature and relative humidity, heating and air conditioning system operation, and outdoor weather. It also was equipped with an automated tracer gas injection and detection system to estimate air change rates every 2 h. Another automated system measured indoor concentrations of total VOCs with a flame ionization detector every 30 min. Active samples for the analysis of VOCs and aldehydes were collected indoors and outdoors on 12 occasions from August 2002 through September 2003. Individual VOCs were quantified by thermal desorption to a gas chromatograph with a mass spectrometer detector (GC/MS). Formaldehyde and acetaldehyde were quantified by high performance liquid chromatography (HPLC). Weather conditions changed substantially across the twelve active sampling periods. Outdoor temperatures ranged from 7 °C to 36 o C. House air change rates ranged from 0.26 h-1 to 0.60 h-1. Indoor temperature was relatively constant at 20 °C to 24 o C for all but one sampling event. Indoor relative humidity (RH) ranged from 21 % to 70 %.