Indoor Formaldehyde Research Articles

Long-Term Formaldehyde Emissions from Medium-Density Fiberboard in a Full-Scale Experimental Room: Emission Characteristics and the Effects of Temperature and Humidity.

We studied formaldehyde emissions from the medium-density fiberboard (MDF) in a full-scale experimental room to approximate emissions in actual buildings. Detailed indoor formaldehyde concentrations and temperature and humidity data were obtained for about 29 months. Temperature, relative humidity (RH), and absolute humidity (AH) ranged over -10.9-31.4 °C, 46.5-83.6%, and 1.1-23.1 g/kgair, respectively. Annual cyclical seasonal variations were observed for indoor formaldehyde concentrations and emission rates, exhibiting entirely different characteristics than those in an environmental chamber under constant environmental conditions. The maximum concentration occurred in summer rather than at initial introduction of the material. The concentrations in summer could be a few up to 20 times higher than that in winter, depending on the indoor temperature and humidity conditions. Concentrations decreased by 20-65% in corresponding months of the second year. Indoor formaldehyde concentrations were positively correlated with temperature and AH but were poorly correlated with RH. The combined effects of temperature and AH on formaldehyde emissions from MDF in actual buildings were verified. These detailed long-term experimental results could be used with environmental chamber measurement data to scale up and validate emission models from chambers held at constant conditions to actual buildings.

Study on the modified montmorillonite for adsorbing formaldehyde

It is very important to develop a cost-effective and environmentally friendly adsorbent for the efficient removal of indoor formaldehyde (HCHO). Herein we present the modified montmorillonite as adsorbents for HCHO. A series of alumina cross-linked montmorillonite with surfactant modification (Al-SCLM) were synthesized in the presence of polyvinyl alcohol (PVA). These adsorbents are safe and cheap, in rich sources, acceptable appearance for daily use. By the characterization such as XRD, FTIR, HCHO adsorption/desorption capacity measurement, it is found that the interlayer environment is a key factor for the superior adsorption capacity of the modified montmorillonite. The introduction of surfactant molecules is very favorable for the improvement of the montmorillonite's adsorption capacity. With optimization, the adsorbing capacity of HCHO over Al-SCLM is obviously superior to conventional inorgano-montmorillonite and organo-montmorillonite, and can be over 80% of that over activated carbon with the same volume. We can conveniently recover the adsorbents by heating them to 353K. The strategy that improving the adsorbing capacity by increasing the interlayer distance of materials with surfactant modification will be crucial for developing highly effective adsorbents for hazardous wastes, and has a good prospect for getting rid of HCHO in industrialization.

Support Morphology-Dependent Catalytic Activity of Pd/CeO₂ for Formaldehyde Oxidation.

To eliminate indoor formaldehyde (HCHO) pollution, Pd/CeO2 catalysts with different morphologies of ceria support were employed. The palladium nanoparticles loaded on {100}-faceted CeO2 nanocubes exhibited much higher activity than those loaded on {111}-faceted ceria nanooctahedrons and nanorods (enclosed by {100} and {111} facets). The HCHO could be fully converted into CO2 over the Pd/CeO2 nanocubes at a GHSV of 10,000 h(-1) and a HCHO inlet concentration of 600 ppm at ambient temperature. The prepared catalysts were characterized by a series of techniques. The HRTEM, ICP-MS and XRD results confirmed the exposed facets of the ceria and the sizes (1-2 nm) of the palladium nanoparticles with loading amounts close to 1%. According to the Pd 3d XPS and H2-TPR results, the status of the Pd-species was dependent on the morphologies of the supports. The {100} facets of ceria could maintain the metallic Pd species rather than the {111} facets, which promoted HCHO catalytic combustion. The Raman and O 1s XPS results revealed that the nanorods with more defect sites and oxygen vacancies were responsible for the easy oxidation of the Pd-species and low catalytic activity.

Experimental Evaluation of Indoor Formaldehyde Decomposition Performance of Atmospheric Plasma Reactor Utilizing Sensor Network

An experimental investigation is conducted into the indoor formaldehyde decomposition performance of an atmospheric plasma reactor with an airflow rate of 200 L/s, discharge power of 50 W, and operating voltage of 8.5 kV, utilizing a sensor network. It is shown that, given an initial formaldehyde concentration of ∼0.2 ppm, the reactor removes 15∼80% of the formaldehyde at a height of 107 cm and 20∼73% at a height of 180 cm after 5.5 hours. Moreover, it is shown that, in decomposing the formaldehyde, the reaction process does not generate O3. Finally, it is shown that the reduction in the formaldehyde concentration is particularly significant near the outlet of the plasma reactor and between the reactor and the door.

Relationships between socioeconomic and lifestyle factors and indoor air quality in French dwellings

BackgroundTo date, few studies have analyzed the relationships between socioeconomic status (SES) and indoor air quality (IAQ). ObjectiveThe aim of this study was to examine the relationships between socioeconomic and other factors and indoor air pollutant levels in French homes. MethodsThe indoor air concentrations of thirty chemical, biological and physical parameters were measured over one week in a sample of 567 dwellings representative of the French housing stock between September 2003 and December 2005. Information on SES (household structure, educational attainment, income, and occupation), building characteristics, and occupants' habits and activities (smoking, cooking, cleaning, etc.) were collected through administered questionnaires. Separate stepwise linear regression models were fitted to log-transformed concentrations on SES and other factors. Logistic regression was performed on fungal contamination data. ResultsHouseholds with lower income were more likely to have higher indoor concentrations of formaldehyde, but lower perchloroethylene indoor concentrations. Formaldehyde indoor concentrations were also associated with newly built buildings. Smoking was associated with increasing acetaldehyde and PM2.5 levels and the risk of a positive fungal contamination index. BTEX levels were also associated with occupant density and having an attached garage. The major predictors for fungal contamination were dampness and absolute humidity. ConclusionThese results, obtained from a large sample of dwellings, show for the first time in France the relationships between SES factors and indoor air pollutants, and believe they should be considered alongside occupant activities and building characteristics when study IAQ in homes.

Study on Indoor Formaldehyde Neutralization by Using Anatase and Rutile Nanotitania

Resin impregnated wooden furniture is one of the major sources of formaldehyde in homes from the use of urea-formaldehyde and phenol-formaldehyde resins as adhesives. Indoors, emission of formaldehyde is accelerated by heat and humidity. Dehumidifiers and air conditioners are recommended to improve indoor air quality but the maintenance is costly and relative humidity in some areas are difficult to control. Due to small band gap energy and large surface area, nanotitania could neutralize formaldehyde gas by photocatalytic phenomenon. A study was carried out to investigate the formulations of pure anatase, pure rutile and mixed rutile and anatase phases which can neutralize formaldehyde within a short time. Comparative study was then performed with a control and the result showed that for the control, there are still significant amount of formaldehyde present after running the sample for one hour.

Novel silicone-based polymer containing active methylene designed for the removal of indoor formaldehyde

Indoor air pollution is caused inevitably due to complicated home decoration, in which formaldehyde is one of the most typical pollutants. It will be a convenient, economical and effective strategy to remove indoor formaldehyde if imparting a feature of formaldehyde removal to decorative coatings. We have successfully explored a novel silicone-based polymer containing active methylene used as a formaldehyde absorbent in coatings via a straightforward transesterification process using inexpensive and easily available chemicals. The polymer has been characterized by 13C NMR, FTIR, GC and GPC. Formaldehyde removal capacity of the coating films containing different contents of the polymer has been investigated. The results indicated that coatings incorporating 4wt% of the polymer could make the coating films exhibit significant improvement on formaldehyde removal including purificatory performance (>85%) and durability of purificatory effect (>60%), compared to those consisting of absorbents without any silicon, and improve yellowing resistance performance, while other properties, such as gloss, adhesion, pencil hardness, flexibility and impact resistance, were kept almost unaffected. The chemical absorption process of the silicone-based polymer filled in interior decorative coatings is demonstrated as a promising technology to purify indoor formaldehyde and thus can reduce the harm to individuals.

Henry’s Law Constant and Overall Mass Transfer Coefficient for Formaldehyde Emission from Small Water Pools under Simulated Indoor Environmental Conditions

The Henry's law constant (HLC) and the overall mass transfer coefficient are both important parameters for modeling formaldehyde emissions from aqueous solutions. In this work, the apparent HLCs for formaldehyde aqueous solutions were determined in the concentration range from 0.01% to 1% (w/w) and at different temperatures (23, 40, and 55 °C) by a static headspace extraction method. The aqueous solutions tested included formaldehyde in water, formaldehyde-water with nonionic surfactant Tergitol NP-9, and formaldehyde-water with anionic surfactant sodium dodecyl sulfate. Overall, the measured HLCs ranged from 8.33 × 10(-6) to 1.12 × 10(-4) (gas-concentration/aqueous-concentration, dimensionless). Fourteen small-chamber tests were conducted with formaldehyde solutions in small pools. By applying the measured HLCs, the formaldehyde overall liquid-phase mass transfer coefficients (KOLs) were determined to be in the range of 8.12 × 10(-5) to 2.30 × 10(-4) m/h, and the overall gas-phase mass transfer coefficients were between 2.84 and 13.4 m/h. The influences of the formaldehyde concentration, temperature, agitation rate, and surfactant on HLC and KOL were investigated. This study provides useful data to support source modeling for indoor formaldehyde originating from the use of household products that contain formaldehyde-releasing biocides.

シマオオタニワタリを用いた緑のカーテンによる室内の二酸化炭素およびホルムアルデヒドの除去

シマオオタニワタリを用いた緑のカーテンによる室内の二酸化炭素およびホルムアルデヒドの除去

Facile Synthesis of 3D Amino-Functional Graphene-Sponge Composites Decorated by Graphene Nanodots with Enhanced Removal of Indoor Formaldehyde

Amino-functional graphene-sponge composites decorated by graphene nanodots (G-GND/S) were synthesized. The preparation technology prevents the loss of nano-materials and reduces the amount of graphene addition. G-GND/S was used as adsorbents to remove formaldehyde, and then their performances for formaldehyde adsorption were evaluated by dynamic adsorption experiment. The adsorption properties of three different materials: sponge, graphene-sponge, and GGND/ S, the breakthrough time and adsorption capacity had been compared, the results showed G-GND/S had better formaldehyde adsorption properties with longer breakthrough time (~2137 min/g) and adsorption ability of formaldehyde (22.8 mg/g). Large amounts of amine groups were the most important factor for the strength enhancement of the adsorption efficiency.

<b>Effects of Room Specifications and Lifestyles of Residents </b><b>on Indoor Formaldehyde Concentrations </b>

<b>Effects of Room Specifications and Lifestyles of Residents </b><b>on Indoor Formaldehyde Concentrations </b>

Study on the Formaldehyde Adsorption Kinetics of Dry Waters

Dry waters with an average diameter of 82 μm were prepared by a high speed mixed route. The formaldehyde absorption kinetics of dry waters was investigated by simulating indoor formaldehyde pollution in glass chamber. The results showed that pseudo-second order model could be used to simulate the adsorption process; the adsorption rate was highest in the initial 60 minutes; when the adsorption lasted for 180 minutes, the adsorption reached equilibrium.

Performance and kinetics of catalytic oxidation of formaldehyde over copper manganese oxide catalyst

Thermo-catalytic oxidation (TCO) has a great potential for formaldehyde removal in terms of both efficiency and lifetime. This study investigated the performance and kinetics of hopcalite catalyst (CuO–MnO2) for indoor formaldehyde removal. The effect of inlet concentration (typical indoor level: 180–1300 ppb) and moisture concentration (typical indoor level: 2000–30,000 ppm) on the reaction rate was studied at four temperature levels (25–180 °C). The relative humidity shows significant influence on the catalytic oxidation of formaldehyde by CuO/MnO2, especially at room temperature level. The catalytic oxidation of formaldehyde by CuO/MnO2 follows the traditional L–H model. The L–H model described the reaction process best. Furthermore, the reaction kinetics considering multiple parameters including concentration, moisture concentration and temperature was proposed based on the L–H model. Good agreement was found between experimental data and the prediction with the modified L–H model.

Indoor air assessment, health risks, and their relationship among elderly residents in urban warrens of Bangkok, Thailand

There are many sources of indoor air pollution in any residence, including combustion sources of tobacco smoke, cooking, engines, heating equipment, and fireplace. Indoor air quality is very important especially for the elderly who spend most of the day indoors, but there are limited studies on warrens of Bangkok, Thailand. This study evaluated volatile organic compounds (VOCs)—benzene, toluene, ethylbenzene, and xylene (BTEX)—and carbonyl compounds (CCs) in elderly residences of five warrens in an urban area in Bangkok. All active indoor and outdoor air samples during a 24-h period were applied to charcoal tubes for BTEX analyses using GC/FID and 2,4-dinitrophenylhydrazine (DNPH) cartridge for CC analyses by HPLC/UV. The median indoor VOC concentrations of benzene, toluene, ethylbenzene, xylene, formaldehyde, acetaldehyde, propionaldehyde, and valeraldehyde were 13.29, 128.51, 5.37, 16.16, 11.41, 4.81, 0.76, and 0.21 μg/m3, respectively. Total indoor VOC concentration (BTEX + CCs) of these warrens ranged from 142.32 to 272.31 μg/m3, which was higher than the outdoor VOC level. Indoor formaldehyde concentration was shown significantly higher than outdoor concentration (p 1). The VOC concentrations were related to health status, specific symptoms of colds, skin irritation, and non-specific symptoms of dizziness and headache. The VOC concentrations were affected by elderly behaviors of indoor smoking (p < 0.01), mosquito repellent/insecticide spraying (p < 0.05), indoor environments of air conditioning (p < 0.001), and exhaust fan (p < 0.001). In conclusion, the elderly in urban warrens had health risk from indoor air quality, which was related to their behaviors. Good ventilation and health promotion should be recommended.

Characterization of indoor air quality and resident health in an Arizona senior housing apartment building

A survey of key indoor air quality (IAQ) parameters and resident health was carried out in 72 apartments within a single low-income senior housing building in Phoenix, Arizona. Air sampling was carried out simultaneously with a questionnaire on personal habits and general health of residents. Mean PM10 concentrations are 66±16, 58±13, and 24±3 μg/m3 and mean PM2.5 concentrations are 62±16, 53±13, and 20±2 μg/m3 for the living room, kitchen, and outdoor balcony, respectively. Median PM10 concentrations are 17, 18 and 17 μg/m3 and median PM2.5 concentrations are 13, 14, and 13 μg/m3, respectively. The initial results indicate that increased indoor particle concentrations coincide with residents who report smoking cigarettes. Indoor formaldehyde concentrations revealed median levels of 36.9, 38.8, and 4.3 ppb in the living room, kitchen, and balcony, respectively. Results show that 36% of living room samples and 44% of kitchen samples exceeded the Health Canada REL for chronic exposure to formaldehyde (40 ppb). Associations between occupants’ behavior, self-reported health conditions, and IAQ are evaluated.Implications:This study provides a characterization of indoor air quality (IAQ) of subsidized apartments for seniors in Phoenix, Arizona. It is important for policy makers to understand the environments in which low-income seniors live, as they are vulnerable to the health impacts from poor IAQ. Formaldehyde concentrations were found to exceed the Health Canada 8-hr reference exposure level (REL) for up to 44% of indoor samples. Particulate matter exposure was governed by resident behavior (i.e., smoking). Associations between occupants’ behavior, IAQ, and self-reported health conditions are evaluated. This work can provide a foundation for subsequent remediation of IAQ conditions.

Subjective Symptoms among Medical Students Associated with Low-Level Formaldehyde Exposure during Gross Anatomy Dissection Courses

Subjective Symptoms among Medical Students Associated with Low-Level Formaldehyde Exposure during Gross Anatomy Dissection CoursesAbstract Number:1574 Mihoko Mori*, Tsuyoshi Saga, Koh-ichi Yamaki, and Tatsuya Ishitake Mihoko Mori* Department of Environmental Medicine, Kurume University School of Medicine, Japan, E-mail Address: [email protected] Search for more papers by this author , Tsuyoshi Saga Department of Anatomy, Kurume University School of Medicine, Japan Search for more papers by this author , Koh-ichi Yamaki Department of Anatomy, Kurume University School of Medicine, Japan Search for more papers by this author , and Tatsuya Ishitake Department of Environmental Medicine, Kurume University School of Medicine, Japan Search for more papers by this author AbstractMedical students and lecturers in Japan are exposed to formaldehyde (FA) during gross anatomy dissection courses. In 2011, our university renovated for the installation of dissection tables equipped with local ventilation systems and replaced the general ventilation system, which reduced the indoor FA level during dissection and the reports of subjective symptoms. This study aimed to clarify whether low-level FA exposure during the course was independently associated with students’ symptoms. We distributed questionnaires to 114 second-year students participating in the course (students exposed to FA) and 123 first-year students who have never participated in the course (students without FA exposure) at our university in May and July of 2013 (1 and 3 months, respectively, after the start of the course). The questionnaire covered 16 subjective symptoms (related to the eye, nose, and throat and indefinite complaints) among the second-year students during the course, current symptoms among the first-year students, sex, age, and allergy status. Participants who reported ‘sometimes’ or ‘often’ experiencing each subjective symptom were classified as having subjective symptoms. We analyzed the association between FA exposure and each subjective symptom using logistic regression analysis with adjusted for sex, age, and allergy symptoms. The symptoms significantly associated with exposure (and the associated odds ratios) were eye soreness (2.35), eye fatigue (1.83), tearing (2.62), itching of the nose (1.76), fatigability (2.42), and listlessness (2.09) in May and eye soreness (4.60), tearing (8.07), itching of the nose (2.15), sore throat (5.05), and fatigability (1.82) in July. The mean FA levels (±standard deviation) across 5 points in our laboratory in May and July were 0.11 (±0.08) ppm and 0.07 (±0.05) ppm, respectively. Even low-level FA exposure was associated with some students’ symptoms.

Study on the Purification Effect of Chlorophytum Comosum on Indoor Formaldehyde

In order to investigate the effect of absorption and purification of indoor formaldehyde by chlorophytum comosum under normal circumstance, chlorophytum comosum is used as the test material and formaldehyde concentration of different closure time is measured by indoor formaldehyde velocimeter. Absorptive capacity of chlorophytum comosum on indoor formaldehyde is analyzed by comparing formaldehyde concentration. The results of experiment show that taking closure time of 24h as an example formaldehyde concentration changes from 0.41 mg/m3 to 0.32 mg/m3 and the removal rate is 21.95% in the room of 15 square meters ,and absorption effect of chlorophytum comosum is good for indoor formaldehyde. Combined with the actual situation chlorophytum comosum can be used in the room place and decorative materials with less formaldehyde content are chosen ,and indoor temperature and humidity remain appropriate to purify indoor formaldehyde by combining with the ventilation method.

Energy and indoor air quality implications of alternative minimum ventilation rates in California offices

The energy and IAQ implications of varying prescribed minimum outdoor air ventilation rates (VRs) in California office buildings were estimated using the EnergyPlus building simulation software tool. Weighting factors were used to scale these model predictions to state wide estimates. Energy use predictions were then verified using surveyed California building energy end use data.Models predicted state wide office electricity use that was within 15% of reported electricity consumption from power utilities. The HVAC energy penalty of providing the current Title-24 VRs was approximately 6%, of the total HVAC energy use. Having economizers installed reduced average indoor formaldehyde exposure by 38% and lowered HVAC EUI by 20%. For California offices with economizers, 50% and 100% increases in Title-24 prescribed minimum VRs increased heating, ventilating, and air conditioning (HVAC) modeled energy use by 7.6% and 21.6%, respectively, while decreasing the annual average workplace formaldehyde exposure by 8.6% and 14.4%, respectively. Economizers increased VRs above the minimum 79% of the time lowering annual average concentrations of formaldehyde. Decreasing minimum VRs below the Title-24 rate would have smaller predicted effects on energy use and comparatively larger effects on formaldehyde concentrations. In buildings without economizers in many climate zones, increasing VRs up to 150% of the current Title-24 minimum would save HVAC energy and significantly reduce formaldehyde.A key conclusion is that raising future minimum VRs in California offices is unlikely to significantly improve time-averaged IAQ in buildings with economizers. Lowering future minimum VRs would be unlikely to deliver substantive energy savings.

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.

The effect of ventilation on indoor exposure to semivolatile organic compounds.

A mechanistic model was developed to examine how natural ventilation influences residential indoor exposure to semivolatile organic compounds (SVOCs) via inhalation, dermal sorption, and dust ingestion. The effect of ventilation on indoor particle mass concentration and mass transfer at source/sink surfaces, and the enhancing effect of particles on mass transfer at source/sink surfaces are included. When air exchange rate increases from 0.6/h to 1.8/h, the steady-state SVOC (gas-phase plus particle phase with log KOA varying from 9 to 13) concentration in the idealized model decreases by about 60%. In contrast, for the same change in ventilation, the simulated indoor formaldehyde (representing volatile organic compounds) gas-phase concentration decreases by about 70%. The effect of ventilation on exposure via each pathway has a relatively insignificant association with the KOA of the SVOCs: a change of KOA from 10(9) to 10(13) results in a change of only 2-30%. Sensitivity analysis identifies the deposition rate of PM2.5 as a primary factor influencing the relationship between ventilation and exposure for SVOCs with log KOA = 13. The relationship between ventilation rate and air speed near surfaces needs to be further substantiated.