A simple method for screening emission sources of carbonyl compounds in indoor air

Sampling Volatile Organic Compound Emissions from Consumer Products: A Review

Volatile organic compounds (VOCs) are common constituents of many consumer products. Although many VOCs are generally considered harmless at low concentrations, some compound classes represent substances of concern in relation to human (inhalation) exposure and can elicit adverse health effects, especially when concentrations build up, such as in indoor settings. Determining VOC emissions from consumer products, such as toys, utensils or decorative articles, is of utmost importance to enable the assessment of inhalation exposure under real-world scenarios with respect to consumer safety. Due to the diverse sizes and shapes of such products, as well as their differing uses, a one-size-fits-all approach for measuring VOC emissions is not possible, thus, sampling procedures must be chosen carefully to best suit the sample under investigation. This review outlines the different sampling approaches for characterizing VOC emissions from consumer products, including headspace and emission test chamber methods. The advantages and disadvantages of each sampling technique are discussed in relation to their time and cost efficiency, as well as their suitability to realistically assess VOC inhalation exposures.

Comparison of rates of direct and indirect migration of phosphorus flame retardants from flame-retardant-treated polyester curtains to indoor dust

In this study, the pathways for migration of phosphorus flame retardants (PFRs), tris(1,3-dichloroisopropyl) phosphate (TDCPP) and tricresyl phosphate (TCsP) which were detected from curtains often, from flame-retardant-treated polyester curtains to indoor dust were investigated. Two possible migration pathways were compared quantitatively: (1) an indirect pathway in which the PFRs in the curtains first evaporate from the curtains and are then adsorbed onto indoor dust and (2) a direct pathway in which the PFRs are directly transferred to dust placed on the curtains. The contribution of the indirect pathway was evaluated by means of emission cell tests, which showed that the area-specific emission rates from curtains treated with PFRs were 0.044 (TDCPP, Curtain 5), 0.17 (TDCPP, Curtain 8), and 0.060 (TCsP, Curtain 12) μg m^-2 h^-1 at 20 °C (averaged during 24 h). The contribution of the direct pathway was evaluated by measurement of the time dependence of PFR concentrations on the indoor dust placed on the curtains. These measurements indicated that PFR concentrations on the dust increased with time and that the direct migration rates of PFRs from curtains treated with PFRs were 4.4 (TDCPP, Curtain 5), 12 (TDCPP, Curtain 8), and 7.0 (TCsP, Curtain 12) μg m^-2 h^-1 at 20 °C (averaged during 24 h), or 71-120 times the indirect migration rate. This result suggests that the direct pathway can be expected to predominate.

Characterization of the variation of carbonyl compounds concentrations before, during, and after the renovation of an apartment at Niterói, Brazil

The present work reports the variation of 31 carbonyl compounds (CC) in an apartment located at Niterói City, Rio de Janeiro State, Brazil. Eight sampling campaigns were conducted through a 1-year period, and three areas (living room, kitchen, and bedroom) were evaluated before, during, and after the renovation activities and reoccupation of the apartment. Samples were collected using SEP-PAK cartridges impregnated with 2,4-dinitrophenylhydrazine, and the hydrazones were analyzed using rapid resolution liquid chromatography with UV detection. The lowest total concentration of CC (19.0 ± 1.5 μg m(-3)) was found before the renovation when the apartment was empty, but door varnishing resulted in highest contamination of the apartment (1386 ± 384 μg m(-3)); however, an important dispersion of CC was observed in the subsequent sampling (148 ± 1.8 μg m(-3)). After apartment reoccupation, the indoor contamination seemed to depend on the routine activities taken there, such as household product use and cooking activities, but apparently, local temperature increase favored the vaporization of the volatile CC from the building materials in the apartment. As far as we are concerned, this is the first study comparing the concentrations of 31 CC in residential areas before, during, and after renovation activities taken in Brazil.

Development of an activated carbon filter to remove NO2 and HONO in indoor air

To obtain the optimum removal efficiency of NO2 and HONO by coated activated carbon (ACs), the influencing factors, including the loading rate, metal and non-metal precursors, and mixture ratios, were investigated. The NOx removal efficiency (RE) for K, with the same loading (1.0 wt.%), was generally higher than for those loaded with Cu or Mn. The RE of NO2 was also higher when KOH was used as the K precursor, compared to other K precursors (KI, KNO3, and KMnO4). In addition, the REs by the ACs loaded with K were approximately 38-55% higher than those by uncoated ACs. Overall, the REs (above 95%) of HONO and NOx with 3% KOH were the highest of the coated AC filters that were tested. Additionally, the REs of NOx and HONO using a mixing ratio of 6 (2.5% PABA (p-aminobenzoic acid)+6% H3PO4):4 (3% KOH) were the highest of all the coatings tested (both metal and non-metal). The results of this study show that AC loaded with various coatings has the potential to effectively reduce NO2 and HONO levels in indoor air.

Formaldehyde emission behavior of building materials: on-site measurements and modeling approach to predict indoor air pollution

The purpose of this paper was to investigate formaldehyde emission behavior of building materials from on-site measurements of air phase concentration at material surface used as input data of a box model to estimate the indoor air pollution of a newly built classroom. The relevance of this approach was explored using CFD modeling. In this box model, the contribution of building materials to indoor air pollution was estimated with two parameters: the convective mass transfer coefficient in the material/air boundary layer and the on-site measurements of gas phase concentration at material surfaces. An experimental method based on an emission test chamber was developed to quantify this convective mass transfer coefficient. The on-site measurement of gas phase concentration at material surface was measured by coupling a home-made sampler to SPME. First results had shown an accurate estimation of indoor formaldehyde concentration in this classroom by using a simple box model.

Evaluation of passenger health risk assessment of sustainable indoor air quality monitoring in metro systems based on a non-Gaussian dynamic sensor validation method

Sensor faults in metro systems provide incorrect information to indoor air quality (IAQ) ventilation systems, resulting in the miss-operation of ventilation systems and adverse effects on passenger health. In this study, a new sensor validation method is proposed to (1) detect, identify and repair sensor faults and (2) evaluate the influence of sensor reliability on passenger health risk. To address the dynamic non-Gaussianity problem of IAQ data, dynamic independent component analysis (DICA) is used. To detect and identify sensor faults, the DICA-based squared prediction error and sensor validity index are used, respectively. To restore the faults to normal measurements, a DICA-based iterative reconstruction algorithm is proposed. The comprehensive indoor air-quality index (CIAI) that evaluates the influence of the current IAQ on passenger health is then compared using the faulty and reconstructed IAQ data sets. Experimental results from a metro station showed that the DICA-based method can produce an improved IAQ level in the metro station and reduce passenger health risk since it more accurately validates sensor faults than do conventional methods.

Small-scale passive emission chamber for screening studies on monoterpene emission flux from the surface of wood-based indoor elements

Analysis of literature data published in the last few years leads to the conclusion that in the process of assessment of emission flux of organic compounds emitted from different types of equipment and finishing materials, new types of devices, among which small-scale passive emission chambers for the performance of in-situ research are designed and applied on a larger scale. These devices can be successfully used for the assessment of emission flux of organic compounds in any location of an apartment, with no interference with its normal exploitation. In the following article the possibility of application of a designed and constructed small-scale passive emission chamber for the evaluation of emission flux of organic compounds (mainly monoterpenes) emitted from the surface of wood-based material made of laminated chipboard has been presented. The emission chamber made from polished stainless steel of the inner volume of 3.65 dm(3) allows for the examination/assessment of emission flux from the surface of 452 cm(2). A diffusive passive sampler was installed inside of the small-scale chamber, which enables collecting samples of the analytes emitted from the examined surface of indoor material. The working time of the passive emission chamber equaled 300 min. The results of preliminary studies show that, the constructed device can be successfully used for screening studies, related with the determination of emission flux of monoterpenes from any type of wood-based flat surface located indoors.