Formaldehyde monitoring in urea-formaldehyde foam-insulated houses in St. John's,Newfoundland, Canada: Correlative field evaluation of a real-time infrared spectrophotometric method

Formaldehyde air levels in a group of houses containing urea-formaldehyde foam insulation (UFFI) in St. John's, Newfoundland, Canada, were measured on at least four separate occasions. The NIOSH method and a portable, commercially available single-beam infrared spectrophotometer was used. No correlation was found to exist between the two methods. The formaldehyde air levels were found to be significantly higher in the group of UFFI-insulated houses than in the control group which did not contain UFFI. Large daily variations in the ambient formaldehyde levels could be observed in some selected UFFI houses, attributable to changes in both exterior and, to a lesser extent, interior conditions. In particular, the effect of direct sunlight on UFFI-containing walls is described.     

Health effects of residence in homes with urea formaldehyde foam insulation: a pilot study

All full-time residents (N = 24) from six homes with urea formal dehyde foam insimulation underwent standardized allergy, respiratory, and neuropsychiatric tests. Skin testing did not reveal an increased prevalence of atopy or reaction to 4% formalin. Spirometry was normal in all subjects, and bronchial reactivity was not significantly different from a population-based response to the same challenge. Memory difficulty was a frequently reported symptom. Memory storage deficits could not be documented, but 11 of 14 subjects had abnormal tests of attention span. Eight of the 11 subjects with attention span deficits had elevated depression scores. Chronic low level exposure to formaldehyde may cause significant mental status changes, but further testing of a larger, randomly population is necessary to evaluate this question.     

Formaldehyde in indoor air: Sources and toxicity

Formaldehyde, a highly reactive gas with a pungent odor, is released from a variety of sources including urea-formaldehyde foam insulation, particle board, and plywood, as well as various combustion processes. Concentrations of formaldehyde associated with the presence of these products are higher indoors than outdoors. Under controlled conditions, formaldehyde causes eye and nasal irritation at air concentrations of 0.24 mg/m³ and above. Exposure, residential or occupational, has been associated with eye, nose, and throat irritation, coughing, wheezing, skin rashes, nausea, and other symptoms. Formaldehyde is also a sensitizer; Individuals who are allergic to formaldehyde, or who suffer from respiratory diseases, are likely to suffer the effects of formaldehyde at even lower concentrations. Based on its known metabolism, reactivity with DNA and other marcomolecules, as well as its mutagenic effects in many test systems, formaldehyde is thought to be genotoxic. Recent studies have indicated that formaldehyde is also a carcinogen in rats and probably in mice. Epidemiological studies to date have been inadequate to determine whether or not formaldehyde is a human carcinogen. Formaldehyde seems to be a direct acting carcinogen and it is likely to pose a carcinogenic risk to humans.     

A passive sampling device for determining formaldehyde in indoor air

A passive sampling device based on the principle of diffusion has been developed for the determination of formaldehyde in ambient air. The sampler consists of a capped glass tube (with approximate dimensions of 2.4 × 9 cm) containing a glass-fiber filter treated with NaHSO₃. In the field, the device collects a sample by being uncapped for a specified sampling time. After being recapped and returned to the laboratory, the filter is analyzed by the chromotropic acid (CTA) method. Laboratory validation studies were conducted by exposing the sampling devices for 1 week to dry formaldehyde gas generated by passing trioxane vapor over an acid catalyst bed. In these tests, formaldehyde concentrations ranged from 0.05 to 0.80 mL/m³. Reproducibility was excellent, with relative standard deviations averaging 5.4% for five constant concentrations. The lower detection limit was determined to be 3.6 mL/m³ h. In an occupational environment an 8-h sample would be sufficient to detect compliance with the OSHA permissible exposure limit of 3 mL/m³; in a residential environment a 1-week sample would allow detection of 0.025 mL/m³ for indoor air quality audits.     

Possible health effects of energy conservation: Impairment of indoor air quality due to reduction of ventilation rate

Efforts to reduce the energy needs to heat or cool dwellings have the potential to create new health hazards. Increases in indoor levels of radon and its progeny from the reduction in air exchange rates add a substantial radioactive burden to the general population. Other indoor pollutants reaching critical concentrations in homes with low air exchange rates are CO and NO₂ from unvented combustion in gas stoves and heaters, tobacco smoke, and asbestos fibers. In addition, insulation materials and certain types of furniture may contribute the toxicant formaldehyde diffusing from foam injected walls or chipboard. Risk estimations using linear dose-response relationships show risk factors per kWh saved which are orders of magnitude greater than for a kWh produced by large power plants using coal, oil, gas, or uranium.     

Setting up the criteria and credit-awarding scheme for building interior material selection to achieve better indoor air quality

Methods, standards, and regulations that are aimed to reduce indoor air pollution from building materials are critically reviewed. These are classified as content control and emission control. Methods and standards can be found in both of these two classes. In the regulation domain, only content control is enforced in some countries and some regions, and asbestos is the only building material that is banned for building use. The controlled pollutants include heavy metals, radon, formaldehyde, and volatile organic compounds (VOCs). Emission rate control based upon environment chamber testing is very much in the nature of voluntary product labeling and ranking, and this mainly targets formaldehyde and VOC emissions. It is suggested that radon emission from building materials should be subject to similar emission rate control. A comprehensive set criteria and credit-awarding scheme that encourages the use of low-emission building material is synthesized, and how this scheme can be practiced in building design is proposed and discussed.     

Evaluation of selected monitoring methods for formaldehyde in domestic environments

Varioys analytical methodologies for the monitoring of formaldehyde (CH₂O) concentrations in domestic environments have been developed and evaluated. A modified CEA Instruments, Inc., analyzer has near-real-time CH₃O-specific analysis capability with an 0.01 mg/m³ detection limit. A solid sorbent, 13X molecular sieve has been utilized in a pumped collection unit with a demonstrated 0.03–12.5 mg/m³ linear dynamic range using sampling periods of ≤ 15 min. The development of screening-type techniques has included (1) a semipermeable-membrane passive sampler for measurements of average CH₂O concentrations over 8–24-h periods, and (2) a visual colorimetric analysis method for semiquantitative CH₂O determinations using solid chemical reagents. A preliminary field evaluation has been completed. The results show excellent agreement between the new CH₂O monitoring methods and a reference sampling and analysis technique. A generation apparatus for the production of CH₂O vapor is also reported with a demonstrated linear dynamic range between 0.003 and 12.5 mg/m³.     

Formaldehyde in China: Production, consumption, exposure levels, and health effects

Formaldehyde, an economically important chemical, is classified as a human carcinogen that causes nasopharyngeal cancer and probably leukemia. As China is the largest producer and consumer of formaldehyde in the world, the Chinese population is potentially at increased risk for cancer and other associated health effects. In this paper we review formaldehyde production, consumption, exposure, and health effects in China. We collected and analyzed over 200 Chinese and English documents from scientific journals, selected newspapers, government publications, and websites pertaining to formaldehyde and its subsequent health effects.Over the last 20 years, China's formaldehyde industry has experienced unprecedented growth, and now produces and consumes one-third of the world's formaldehyde. More than 65% of the Chinese formaldehyde output is used to produce resins mainly found in wood products — the major source of indoor pollution in China. Although the Chinese government has issued a series of standards to regulate formaldehyde exposure, concentrations in homes, office buildings, workshops, public places, and food often exceed the national standards. In addition, there have been numerous reports of formaldehyde-induced health problems, including poisoning and cancer. The lack of quality epidemiological studies and basic data on exposed populations emphasizes the need for more extensive studies on formaldehyde and its related health effects in China.     

Comparison of the chromotropic acid and modified pararosaniline methods for the determination of formaldehyde in air

Follow-up tests were performed in 25 complaint homes previously investigated by the Wisconsin Division of Health to determine ambient formaldehyde concentrations. Four collection methods were compared in each home: (1) midget impingers containing double-distilled water and immersed in ice baths, (2) midget impingers containing 1% sodium bisulfite solution and immersed in ice baths, (3) midget impingers containing cold 1% sodium bisulfite solution (temperature not maintained with an ice bath), and (4) a refrigerated, complete sampling unit developed at Lawrence Berkley Laboratory which utilized double-distilled water as a collection medium. Air was drawn through the midget impingers using personal sampling pumps. All four types of sampling trains were operated simultaneously in a bedroom, collecting specimens within an area of about 4 ft², while in the kitchen or living room, all sampling trains except for the impingers containing 1% sodium bisulfite solution and immersed in ice baths were operated together. Analysis of variance indicated that the three samples collected using midget impingers and personal sampling pumps gave similar results. All specimens collected in water were analyzed using both the chromotropic acid and pararosaniline analytical methods. Quality control specimens prepared in the laboratory showed excellent agreement between the two methods; however, field specimens through which air had been drawn were assigned lower values using the pararosaniline method. Special precautions were taken to ensure that specimens collected in water were not contaminated with sodium bisulfite, a serious interference for the pararosaniline test. To rule out the possibility that specimens deteriorated between analysis, test results from each method were confirmed by repeating each method for selected sets of specimens for a period of several days. It was hypothesized that some source of interference was present in the field specimens which affected the pararosaniline analysis. Statistical tests were applied to determine whether the observed discrepancy between the analytical methods was consistent and a regression model was employed to determine whether any of the other environmental parameters measured during sample collection was associated with the discrepancy.     

Formaldehyde in conventional homes in Taiwan

A survey was conducted in the humid environment of Taipei City during April and May of 1991, to investigate the indoor formaldehyde exposure and its health effects on 117 conventional households. The levels of formaldehyde were measured by the pararosaniline method. The details regarding construction, ventilation, combustion of fuel, burning of Chinese incense, and the complaints concerning the respiratory system were obtained by a questionnaire. The results show that the age of the pressed wood used in furniture and indoor decoration, the ventilation rate, the combustion of fuel, and the burning of Chinese incense significantly affect the levels of formaldehyde. The respiratory complaints found in this study were concluded here to be only partially accounted for by exposure to formaldehyde.     

Formaldehyde and skin carcinogenesis

Groups of 32 animals (16 males/16 females) were given topical application of 200 μg 1% formaldehyde or 10% formaldehyde in water on the backskin twice a week. Two other groups were painted with 51.2 μg DMBA in 100 μL reagent grade acetone: one was followed 9 days later with applications of 200 μl 10% formaldehyde in water twice a week, and the other with 17 nmol TPA in 100 μL acetone twice a week. A fifth group of 176 mice was treated once with 51.2 μg DMBA in acetone and given no further treatment. The animals were painted and/or observed for 60 weeks. The animals painted once with DMBA alone were observed for 80 weeks. Animals receiving 1 and 10% formaldehyde alone developed no tumors. The 176 mice painted once with DMBA developed 225 skin tumors in 85 animals. Six of them were squamous cell carcinomas and 2 animals had lymphosarcomas. In the group painted with DMBA and then followed by formaldehyde, three animals had lung adenomas, and 11 had neoplastic growths of te skin (three squamous cell carcinomas and 22 papillomas). The final tumor rate after DMBA initiation followed by formaldehyde was not significantly different from the final tumor rate after DMBA alone, but the time of appearance of the first tumor and the mean latency time was significantly or very significantly, reduced. Hence, under the experimental conditions used formaldehyde had no carcinogenic potency of its own but did shorten the latency time in DMBA-induced carcinogenesis.Formaldehyde has also acute toxic and irritating effects. It is therefore important to induce practical methods for reducing exposure to formaldehyde in pathology laboratories.     

Effect of sample conditioning and chamber loading on rate of formaldehyde release from wood products in a desiccator test

Several variables may influence the observed rate of formaldehyde (CH₂O) offgassing from wood products in a small static test chamber. We studied the effect of sample conditioning at ≈100% relative humidity and chamber loading (sample size) on CH₂O release rate from particle board (PB) and plywood (PW). Samples of PB and PW were placed in glass desiccators with reservoirs of water at a loading of 21 m²/m³ (sample surface area per chamber volume). The rate of CH₂O offgassing from the PB did not change over several weeks under these conditions (0.24 μg/cm²/day), but the overall release rate from the PW decreased after 8 days. In another experiment, the loading of the desiccator had a major effect on the rate of CH₂O offgassing from PB over a loading range of 1 to 42 m²/m³. The same phenomenon was observed with different loadings of PW. The inverse of the observed release rate varied linearly with the chamber loading of PB or PW. At a loading which may be encountered in a house (0.25 m²/m³), the release rate coefficient for PB calculated from the above inverse relation was 22-fold higher than that measured at a more conventional test load of 21 m²/m³. These results indicate that great care should be exercised when using desiccator tests for assessing and comparing the potential strength of materials as sources of CH₂O in the indoor environment.     

Removal of nitrogen oxides with organic amines and metal complexes

Aqueous solutions containing organic amines and metal complexes were applied for the removal of nitrogen oxides. Organic amines were effective for the removal of the mixture composed of nitric oxide and nitrogen dioxide. In particular, methyl and ethyl amines removed these species with 1 : 1 ratio from the mixture at fairly rapid rates. Dinitrogen trioxide (N₂O₃) was suggested to be involved in the course of the removal.Metal complexes removed nitrogen dioxide efficiently. As has been previously reported for a number of inorganic or organic redox systems, it was concluded that the removal of nitrogen dioxide by metal complexes proceeded also by the redox mechanism.Iron (ii) chelate complexes were highly effective for the removal of nitric oxide and this was attributed to a reversible coordination to the complex.     

Association of organic matter, iron and inorganic phosphorus in lake waters

Gel permeation chromatography was used to fractionate ³²PO₄³⁻ labelled components by molecular size in filtered, destabilized lake foam, concentrated lake water, and lake sediment extracts. Evidence is presented for the abiotic formation of organic matter iron inorganic P complexes in lake foam, water and sediments. ³²PO₄^staggered was found to excahnge with low molecular weight, dissolved P fraction, probably an organic matter -Fe- inorganic P complex, but not with a high molecular weight, non-inorganic dissolved reactive P pool, hypothesized to be similar to the dimer. Our experiments suggest that inorganic P binding by high molecular weight organic matter may play a significant role in the P cycle. If the bound P is unavailable to algae and bacteria, the complexes could explain Rigler's (1968) hypothesis that the molybdenum blue technique may overestimate the free orthophosphate concentration by 10–100 times.     

Urinary biomarkers of flame retardant exposure among collegiate U.S. gymnasts

Flame retardants are widely used in polyurethane foam materials including gymnastics safety equipment such as pit cubes and landing mats. We previously reported elevated concentrations of flame retardants in the air and dust of a U.S. gymnastics training facility and elevated PentaBDE in the serum of collegiate gymnasts. Our objective in this pilot study was to compare urinary biomarkers of exposure to other flame retardants and additives of polyurethane foam including tris(1,3-dichloro-2-propyl) phosphate (TDCIPP), triphenyl phosphate (TPHP) and 2-ethylhexyl- 2,3,4,5-tetrabromobenzoate (EH-TBB) in samples collected from 11 collegiate gymnasts before and after a gymnastics practice (n = 53 urine samples total). We identified a 50% increase in the TPHP biomarker (p = 0.03) from before to after practice, a non-significant 22% increase in the TDCIPP biomarker (p = 0.14) and no change for the EH-TBB biomarker. These preliminary results indicate that the gymnastics training environment can be a source of recreational exposure to flame retardants. Such exposures are likely widespread, as we identified flame retardants in 89% of foam samples collected from gyms across the U.S.     

Elevated levels of PFOS and PFHxS in firefighters exposed to aqueous film forming foam (AFFF)

Exposure to aqueous film forming foam (AFFF) was evaluated in 149 firefighters working at AFFF training facilities in Australia by analysis of PFOS and related compounds in serum. A questionnaire was designed to capture information about basic demographic factors, lifestyle factors and potential occupational exposure (such as work history and self-reported skin contact with foam). The results showed that a number of factors were associated with PFAA serum concentrations. Blood donation was found to be linked to low PFAA levels, and the concentrations of PFOS and PFHxS were found to be positively associated with years of jobs with AFFF contact. The highest levels of PFOS and PFHxS were one order of magnitude higher compared to the general population in Australia and Canada. Study participants who had worked ten years or less had levels of PFOS that were similar to or only slightly above those of the general population. This coincides with the phase out of 3M AFFF from all training facilities in 2003, and suggests that the exposures to PFOS and PFHxS in AFFF have declined in recent years. Self-reporting of skin contact and frequency of contact were used as an index of exposure. Using this index, there was no relationship between PFOS levels and skin exposure. This index of exposure is limited as it relies on self-report and it only considers skin exposure to AFFF, and does not capture other routes of potential exposure. Possible associations between serum PFAA concentrations and five biochemical outcomes were assessed. The outcomes were serum cholesterol, triglycerides, high-density lipoproteins, low density lipoproteins, and uric acid. No statistical associations between any of these endpoints and serum PFAA concentrations were observed.     

Exposure to major volatile organic compounds and carbonyls in European indoor environments and associated health risk

This paper summarizes recent data on the occurrence of major organic compounds (benzene, toluene, xylenes, styrene, acetaldehyde, formaldehyde, naphthalene, limonene, α-pinene and ammonia, classified by the European Commission's INDEX strategy report as the priority pollutants to be regulated) and evaluates accordingly cancer and non-cancer risks posed by indoor exposure in dwellings and public buildings in European Union (EU) countries. The review process indicated that significant differences in indoor air quality exist within and among the countries where data were available, indicating corresponding differences in sources and emission strength of airborne chemicals, identified or not. Conservative exposure limits were not exceeded for non-carcinogenic effects, except for formaldehyde; for carcinogenic agents the estimated risks were up to three orders of magnitude higher than the one (10(-6)) proposed as acceptable by risk management bodies. However, the risk assessment evaluation process faces crucial difficulties, either due to the relative paucity of indoor air quality measurements in many EU countries, or by the lack of sampling consistency in the already existing studies, indicating the need for additional measurements of indoor air quality following a harmonized sampling and analytical protocol. Additionally, uncertainties embodied in the cancer potency factors and exposure limit values impose further difficulties in substance prioritization and risk management.     

Interactions of secondary amines with bentonite clay and humic materials in dilute aqueous systems

The speciation of dimethylamine, diethylamine, dibutylamine, and diethanolamine on bentonite clay saturated with 1) Na and Ca cations, 2) dodecyltrimethylammonium cation, and 3) tannic acid, and on humic acid and peat, has been studied. Adsorption isotherms were determined and the effect of ionic strength and pH on the adsorption were studied. The results show that the amines react with the particulates by ion exchange mechanisms. Hydrogen bonding seems to also contribute to the binding of dibutylamine.     

Low-infiltration housing in Rochester, New York: A study of air-exchange rates and indoor air quality

A sample of 58 occupied homes in Rochester, NY, most of which incorporated special builder-designed weatherization components, were studied to assess (1) the effectiveness of construction techniques designed to reduce air leakage; (2) the indoor air quality and air-exchange rates in selected airtight houses, and (3) the impact on indoor air quality of mechanical ventilation systems employing air-to-air heat exchangers. The “specific leakage area” was measured in each house using the fan pressurization technique. Houses built with polyethylene vapor barriers and joint-sealing were as a group 50% tighter than a similar group of houses without such components. Mechanical ventilation systems with air-to-air heat exchangers were installed in nine relatively airtight houses, some of which had gas stoves and/or tobacco smoking occupants. Air-exchange rates and indoor concentrations of radon (Rn), formaldehyde (HCHO), nitrogen dioxide (NO₂), and humidity were measured in each house for 1-week periods with and without mechanical ventilation. More detailed measurements, including concentrations of carbon monoxide and inhalable particulates, were made in two of these houses by a mobile laboratory. In all nine houses, air-exchange rates were relatively low (0.2–0.5 ach) without mechanical ventilation, and yet indoor concentrations of Rn, HCHO, and NO₂ were below existing guidelines. Mechanical ventilation systems were effective in further reducing indoor contaminant concentrations. We conclude that when contaminant source strengths are low, acceptable indoor air quality can be compatible with low air-exchange rates.     

Australian firefighters' exposure to air toxics during bushfire burns of autumn 2005 and 2006

Bushfire fighting is a hazardous occupation and control strategies are generally in place to minimize the hazards. However, little is known regarding firefighters' exposure to bushfire smoke, which is a complex mixture of toxic gases and particles. In Australia, during the prescribed burning season, firefighters are likely to be exposed on a regular basis to bushfire smoke, but whether these exposures affect health has yet to be determined. There are a number of factors that govern whether exposure to smoke will result in short-term and/or long-term health problems, including the concentrations of air pollutants within the breathing zone of the firefighter, the exposure duration, and health susceptibility of the individual, especially for pre-existing lung or heart disease. This paper presents measurements of firefighters' personal exposure to bushfire smoke, the first step within a risk management framework. It provides crucial information on the magnitude, extent and frequency of personal exposure to bushfire smoke for a range of typical scenarios. It is found that the primary air toxics of concern are carbon monoxide (CO), respirable particles and formaldehyde. Also, work activity is a major factor influencing exposure with exposure standards (both average and short-term limits) likely to be exceeded for activities such as suppression of spot fires, holding the fireline, and patrolling at the edge of a burn area in the urban-rural interface.