Formaldehyde Concentration In Air Research Articles

Determination of formaldehyde in indoor air by active and passive sampling methods

Formaldehyde (HCHO), the simplest molecule of the aldehyde group, is a toxic gas commonly found in indoor air. Many analysis methods have been developed to determine concentrations of formaldehyde in air, including sampling methods (active sampling and passive sampling), analytical methods (spectrophotometry, chromatography), and sensors. In general, the active sampling method is the standard and widely used method, and the passive sampling method is relatively simple, low-cost, and easy to implement. Gas sensing, meanwhile, is a quick detection method and has a lot of research potential. The purpose of this article is to compare analytical methods of formaldehyde in air and to summarize their advantages and disadvantages. This paper also focuses on HCHO passive samplers (the principle of operation, sampler geometries (tube, badge), validation experiments in the laboratory, and their applications in the determination of HCHO in personal/indoor air.

AERMOD Application for Assessment of Formaldehyde Emission Dispersion from Chipboard Production

The results of modeling the formaldehyde dispersion from the chipboard production at the plant in Ivatsevichi (the Brest region, the Republic of Belarus) are presented. The AERMOD Gaussian model developed by the U.S. Environmental Protection Agency (EPA) is applied. Maximum hourly concentrations of formaldehyde at the distance to 3 km from emission sources are calculated. The simulation results are verified by under-plume measurements of formaldehyde concentration in air at the distance to 650 m from the sources as well as near the sources of formaldehyde releases. The correlation between the measured and simulated concentrations is demonstrated. The sources of uncertainty of the results associated with the shortage of available meteorological information with a required temporal resolution are described.

О НЕОБХОДИМОСТИ СИНХРОНИЗАЦИИ ПРАВИЛ И МЕТОДОВ ИССЛЕДОВАНИЯ ПОКАЗАТЕЛЕЙ БЕЗОПАСНОСТИ НЕПРОДОВОЛЬСТВЕННОЙ ПРОДУКЦИИ В СООТВЕТСТВИИ С ТРЕБОВАНИЯМИ ТЕХНИЧЕСКИХ РЕГЛАМЕНТОВ ТАМОЖЕННОГО СОЮЗА

The article considers problematic practical moments of compliance with the rules and methods of research of safety indicators of non-food products in accordance with the requirements of the Technical Regulations of the Customs Union. The authors give examples of the inconsistency of the measurement procedures presented in the lists, indicated in the lists of various technical regulations for the study of non-food products, directly affects the work of laboratories and limits their ability to conduct research. Using the example of methods for determining the concentration of formaldehyde in air extracts indicated in different technical regulations for non-food products, it is shown that in practice there are situations when the same safety index for different groups of goods is investigated according to different measurement methods. It has been shown that until now in the lists of documents in the field of standardization, containing rules and methods of research (testing) and measurements, there are methods that do not meet the sensitivity requirements specified in the same technical regulations, as well as certain documents that have become invalid. Proposals on synchronization of rules and methods for researching the safety indicators of non-food products for timely provision of sanitary and epidemiological surveillance with objective data on valid up-to-date documents have been developed.

Analysis of the main factors affecting the concentration of formaldehyde in the air.

In the article the main factors affecting the concentration of formaldehyde in indoor air and the streets of Kyiv. The main factor influencing the concentration of formaldehyde in the air is a fire. In August and September 2015 exceeded the normal concentration of 1.2 -4 times. Seasonal cycle charting the course of the annual concentration of formaldehyde leads to the idea of seasonal factors that contribute to its fluctuations. As a result of the analysis, it was found that the analysis of indoor air is conducted only at the request and has no statistical nature. No information database created major factors pollution formaldehyde and not developed regulatory documents.

Formaldehyde in Urban Air

The properties of formaldehyde in the environment, approaches to the valuation of its content in the air, measuring techniques, and the main sources of its releases to the environment are discussed. An overview of the measured concentrations of formaldehyde in the air in the cities of Belarus and other CIS countries, Europe and the USA. It is shown that the average concentration of formaldehyde in ambient air of cities of the CIS as a whole are close to the average annual levels of content in the cities of Europe and somewhat lower than in the U.S.

Sn-Doped In2O3 Nanocrystalline Thin Films Deposited by Spray Pyrolysis: Microstructural, Optical, Electrical, and Formaldehyde-Sensing Characteristics

Undoped and Sn-doped (1, 1.5 and 2 at.%) indium oxide (In2O3) thin films have been grown by the chemical spray pyrolysis technique on cleaned glass substrates using indium nitrate [In(NO3)3] and stannic tetrachloride hydrated (SnCl4·5H2O) as the host and dopant precursors, respectively, and deionized water as the solvent. Structural characterization using x-ray diffraction reveals that the films possess cubic structure, with the average crystallite size in the range 10-14 nm. The surface morphology and roughness of the films have been investigated by means of an atomic force microscope. UV-Vis measurements indicate an enhancement in the optical transmittance in the visible region on Sn doping. Further, the doping effect has been found to substantially reduce the electrical resistance to a few orders of magnitude of the undoped In2O3 film. We report a simultaneous improvement in both the optical and electrical properties of indium oxide thin film due to the doping of Sn ions. These results indicate that Sn-doped In2O3 thin film can be a potential candidate for use in various optoelectronic devices. Among all the films examined, the 1 at.% Sn-doped film shows the maximum response (~91%) at 300 °C for 80 ppm concentration of formaldehyde in air.

Formaldehyde Gas Sensors: A Review

Many methods based on spectrophotometric, fluorometric, piezoresistive, amperometric or conductive measurements have been proposed for detecting the concentration of formaldehyde in air. However, conventional formaldehyde measurement systems are bulky and expensive and require the services of highly-trained operators. Accordingly, the emergence of sophisticated technologies in recent years has prompted the development of many microscale gaseous formaldehyde detection systems. Besides their compact size, such devices have many other advantages over their macroscale counterparts, including a real-time response, a more straightforward operation, lower power consumption, and the potential for low-cost batch production. This paper commences by providing a high level overview of the formaldehyde gas sensing field and then describes some of the more significant real-time sensors presented in the literature over the past 10 years or so.

Formaldehyde in hair straightening products: Rapid 1H NMR determination and risk assessment

Despite official regulations, the illegal use of formaldehyde-containing or releasing hair straightening products has become a popular practice in Europe and high contents of formaldehyde in such products have been reported. In this study, a methodology utilizing (1)H NMR spectroscopy has been developed to measure the concentration of formaldehyde in hair straightening products. For sample preparation, a dilution and alkaline hydrolysis is required. The total formaldehyde content can then be quantified by a distinct peak of the CH2 group of the methanediol molecule in the δ4.84-4.82 ppm range. The developed methodology was applied for the analysis of 10 hair straightening products. Seven of these products contained detectable amounts of formaldehyde that were higher than the maximum allowed concentration of 0.2%. The formaldehyde content of these products was found to be in the range 0.42-5.83% with an average concentration of 1.46%. The accuracy and reliability of the NMR results were confirmed by the EU reference photometric method. The air formaldehyde concentrations after application of hair straightening products were estimated in ranges 20-423 ppm and 1-18 ppm (for 1 and 24 m(3) salon volume). A probabilistic exposure estimation using Monte Carlo simulation found the average formaldehyde concentration to be 6 ppm (standard deviation 15 ppm). All exposure scenarios considerably exceeded the safe level of 0.1 ppm. Our findings confirmed that the risk of cosmetic formulations with formaldehyde above 0.2% is not negligible, as these products may facilitate considerable exposure of formaldehyde for consumers especially for salon workers.

Formaldehyde and tobacco smoke as alkylating agents: The formation of N-methylenvaline in pathologists and in plastic laminate workers

ObjectiveAim of this study was to investigate the relationships between the concentration of formaldehyde in air and the alkylation of hemoglobin to form a terminal N-methylenvaline residue in three occupationally exposed groups: a) technicians of pathology wards, b) workers of the plastic laminates industry, and c) a control group. All subjects recruited in this study were also tested on their smoking habits. MethodsFormaldehyde adsorbed on passive air samplers was quantified by HPLC with UV detection (360nm), cotinine was quantified by GC–MS. Terminal hemoglobin N-methylenvaline was determined by treating globine under reducing conditions with pentafluorophenyl isothiocyanate to yield a derivative, subsequently detected by GC–MS. One-way analysis of variance was performed to compare among the three groups the biomarkers considered in this study. ResultsFor air-FA and N-methylenvaline a difference between the three groups was detected (p<0.0001) and a significant higher concentration in the two professionally exposed groups was proved. Mean values for FA (μg/m3): group a) 188.6, group b) 210.1, and group c) 41.4; mean values for N-methylenvaline (nmol/g of globin): group a) 377.9, group b) 342.8, and group c) 144.8. Conversely, the comparison between the two professionally exposed groups, a) vs b), does not show any significant difference highlighting similar exposition to FA and, consequently, similar biological response. Tobacco smoke proves to have a minor impact on the formation of N-methylenvaline molecular adduct. ConclusionsA positive correlation was demonstrated between professional exposition to air-formaldehyde and hemoglobin alkylation to form N-methylenvaline molecular adduct in two occupationally exposed groups of subjects considered in the present study. In comparison with occupational exposition, tobacco smoke proved to have a minor impact on the formation of N-methylenvaline molecular adduct.

Effect of a Furniture Interior Air Purifying Device on Reducing Concentrations of Formaldehyde in Air

Effect of a furniture interior air purifying device on reducing concentrations of formaldehyde in air

Malondialdehyde−Deoxyguanosine Adduct Formation in Workers of Pathology Wards: The Role of Air Formaldehyde Exposure

Formaldehyde is an ubiquitous pollutant to which humans are exposed. Pathologists can experience high formaldehyde exposure levels. Formaldehyde-among other properties-induce oxidative stress and free radicals, which react with DNA and lipids, leading to oxidative damage and lipid peroxidation, respectively. We measured the levels of air-formaldehyde exposure in a group of Italian pathologists and controls. We analyzed the effect of formaldehyde exposure on leukocyte malondialdehyde-deoxyguanosine adducts (M(1)-dG), a biomarker of oxidative stress and lipid peroxidation. We studied the relationship between air-formaldehyde and M(1)-dG adducts. Air-formaldehyde levels were measured by personal air samplers. M(1)-dG adducts were analyzed by a (32)P-postlabeling assay. Reduction room pathologists were significantly exposed to air-formaldehyde with respect to controls and to the pathologists working in other laboratory areas (p < 0.001). A significant difference for M(1)-dG adducts between exposed pathologists and controls was found (p = 0.045). The effect becomes stronger when the evaluation of air-formaldehyde exposure was based on personal samplers (p = 0.018). Increased M(1)dG adduct levels were only found in individuals exposed to air-formaldehyde concentrations higher than 66 microg/m(3). When the exposed workers and controls were subgrouped according to smoking, M(1)-dG tended to increase in all of the subjects, but a significant association between M(1)-dG and air-formaldehyde was only found in nonsmokers (p = 0.009). Air-formaldehyde played a role positive but not significant (r = 0.355, p = 0.075, Pearson correlation) in the formation of M(1)-dG, only in nonsmokers. Working in the reduction rooms and exposure to air-formaldehyde concentrations higher than 66 microg/m(3) are associated with increased levels of M(1)-dG adducts.

Air concentrations of VOCs in portable and traditional classrooms: results of a pilot study in Los Angeles County.

Recent state and federal public school class-size reduction initiatives, increased elementary and pre-K enrollment driven by population growth and immigration, and limited resources for capital projects, modernization, and maintenance at aging schools have increased the prevalence of prefabricated, portable classrooms (portables). At present, approximately one of three California students are taught in portables, whose use is especially prevalent in more populated counties such as Los Angeles, home to the nation's second largest school district. Limited data existed on chemical compound air concentrations, and thus exposures, inside American public schools. Measurements have been limited, usually performed in complaint schools, and varied in sampling protocols and analysis methods. To address a school environment and children's health issue of present concern, an assessment of public school portables was conducted in Los Angeles County. Seven schools in two school districts were recruited, from which 20 classrooms--13 portables, seven in main buildings--were randomly selected. We report indoor air concentrations of 21 target toxic and odorous volatile organic compounds (VOCs), including formaldehyde and acetaldehyde, measured with passive samplers (DNSH PAKS and 3M OVM 3500) in the cooling and heating seasons between June 2000 and June 2001. None of the measured indoor air formaldehyde concentrations exceeded the existing California Air Resources Board guideline (50 ppb, or 60 microg/m(3)). The main sources of aldehydes in classrooms, especially portables, were likely interior finish materials and furnishings made of particleboard without lamination. Indoor air VOC concentrations were generally low in this pilot study. The four most prevalent VOCs measured were toluene, m-/p-xylene, alpha-pinene, and delta-limonene; likely indoor sources were personal, teaching, and cleaning products. Future schools research should attempt larger samples over larger geographical areas.

Isoprene and its degradation products as strong ozone precursors in Insubria, Northern Italy

Frequent smog episodes occur during spring, summer, and autumn in Insubria, Northern Italy. On a test site in this area the atmospheric concentration of the photo-oxidants ozone and peroxyacetyl nitrate has been monitored over a year (2000) together with ozone precursors listed in the European Union Air Quality Directive 2002/3/EC, such as nitrous oxides (NO X ) and volatile organic compounds (VOC) including hydrocarbons and carbonyls. The results of this study revealed a strong impact of biogenic isoprene on the air quality. In winter isoprene was detected at the ppt level and correlated with anthropogenic VOC. However, during the growing season isoprene exhibited a distinct diurnal variation with maximum concentrations late in the afternoon reaching up 70 ppbC attributed to strong emissions from the abundant vegetation of broad-leaf deciduous trees in this area. A new HPLC-MS method was developed for the determination of isoprene's primary atmospheric oxidation products methacrolein as its 2,4-dinitrophenylhydrazone and methyl vinyl ketone as an unusual double derivative with 2,4-dinitrophenylhydrazine. Methacrolein and methyl vinyl ketone followed the same diurnal and annual trends as isoprene. The average monthly concentration of isoprene and these products ranged from around 10 ppbC in June, July and September to 20 ppbC in August, which constitutes 15–30% of C 3–C 9 VOCs. The contribution from isoprene photo-oxidation to the ambient air formaldehyde concentrations was also found to be high during this period ranging from 30% to 60% in May, June, July and August. From the atmospheric VOC and NO X concentrations the local photochemical ozone formation was estimated by the incremental reactivity approach. The calculations showed that in summer isoprene's contribution to the local ozone formation was as high as 50–75%.

Gas chromatographic determination of formaldehyde in air using solid-phase microextraction sampling

The optimization of in situ derivatization and preconcentration of formaldehyde in air using solid phase microextraction with gas chromatographic determination was investigated. A dimethylpolysiloxane coating (7 μm) solid-phase microextraction needle was used in the final procedure as a support for derivatizing reagents such as 2,4-dinitrophenylhydrazine and acetylacetone. Standard concentrations of formaldehyde in air were obtained using a headspace technique and equilibrium concentrations of formaldehyde in air were calculated using Henry's law. After derivatization on the fiber, the derivative was thermally desorbed in the injector of a gas chromatograph and analyzed using an electron capture detector. A detection limit of 0.17 mg m−3 was obtained. Calibration was done at 296 K. Reproducibility of the method was 9.6%. Some real air samples were also analyzed. The method is very convenient and ideal for the rapid determination of formaldehyde in air.

Detection and Estimation of Part-per-Billion Levels of Formaldehyde Using a Portable High-Throughput Liquid Absorption Air Sampler

In view of the known adverse health effects of formaldehyde and its suspected carcinogenicity, a convenient and simple apparatus for its rapid detection is highly desirable. A portable high-throughput liquid absorption air sampler (PHTLAAS) was therefore evaluated for the rapid and ultrasensitive detection of formaldehyde. Controlled concentrations of formaldehyde in air were generated with a constant-drive syringe pump and mixing chamber apparatus and were either sampled by the PHTLAAS, at a rate of about 200 L/min, or fed to two series-connected liquid impingers. In either case, the formaldehyde was absorbed in a small volume of aqueous sodium bisulfite and measured by the chromotropic acid method. The reddish-purple color of the chromogen formed with chromotropic acid provides a sensitive test for the screening of low levels of formaldehyde in ambient air. Comparison of samples collected from the test sampler with those from the impingers before and after each test yielded PHTLAAS collection efficienci...

Energy dependencies of the proton transfer reactions [formula omitted

The proton transfer reaction system H 3O + + CH 2O ⇎CH 2OH + + H 2O has been investigated in both directions as a function of the mean relative kinetic energy, KE cm, between the reactants from 0.05 eV to 1 eV in a selected ion flow drift tube (SIFDT) experiment. The rate constant k f for the forward channel follows closely the calculated collisional limiting value, k c, showing a slightly negative energy dependence. The rate constant, k r, for the reverse channel, which is endoergic by 5.2 kcal mol −1, increases from k r = 2.3 × 10 −12 cm 3 s −1 at KE cm = 0.05 eV to k r = 2 × 10 −10 cm 3 s −1 at KE cm = 1 eV. This endoergic reaction is paralleled by an associative channel forming CH 2OH +·H 2O, which undergoes ligand switching with water molecules to produce H 3O +·H 2O, yielding a bond energy BE(CH 2OH +−H 2O) = 27.7 kcal mol −1 in agreement with previous data. The present results are important requisites to monitor the formaldehyde concentrations in air using proton transfer reactionmass spectrometry (PTR-MS).

Effects of Climatic Parameters on Formaldehyde Concentrations in Indoor Air

The results of measurements of indoor air formaldehyde concentrations in occupational and private residences are presented for the period 1986 to 1993, based on requests of persons who complained about irritations. In many cases, climatic parameters such as the air exchange rate, temperature and relative humidity were also monitored. Calculated mean values for temperature and humidity were 22°C and 45% respectively. The average air exchange rate was 0.36 h−1, which is well below a recommended guideline value of 0.8 h˜' and it was evident that the ventilation is clearly insufficient in many rooms. The average formaldehyde concentration was 119 μg/m −3 (252 data), which is only slightly below the German guideline value of 125 μg/m −3. In 31% of the cases this guideline was exceeded. As expected, a clear relation between formaldehyde concentrations and the air exchange rate was found. The highest levels result at AE≤0.8 h−1, but only a single value exceeds 125 μg/m −3 at AE≥0.8 h−1. The association of law ventilation rates with high formaldehyde levels is also evident from a comparison with theoretical data after normalization to AE=0.8 h−1, using the Hoetjer-equation. It was also observed that the calculated annual mean concentrations decreased from 1986 to 1993.

Effect of an Ozone-Generating Air-Purifying Device on Reducing Concentrations of Formaldehyde in Air

Abstract Formaldehyde, an air contaminant found in many indoor air investigations, poses distinct occupational exposure hazards in certain job categories (e.g., mortuary science) but is also of concern when found or suspected in office buildings and homes. A variety of air-purifying devices (APDs) are currently available or marketed for application to reduce or remove concentrations of a variety of indoor air pollutants through the use of ozone as a chemical oxidant. An investigation was conducted to determine if concentrations of formaldehyde similar to those found in industrial hygiene evaluations of funeral homes could be reduced with the use of an ozone-generating APD. An ozone-generating APD was placed in an exposure chamber and formaldehyde-containing embalming solution was allowed to evaporate naturally, creating peak and mean chamber concentrations of 2.5 and 1.3 ppm, respectively. Three 90-minute evaluations were conducted to establish a change in concentration for formaldehyde generated in the c...

Permeation-solid adsorbent sampling and GC analysis of formaldehyde

A passive method with membrane permeation sampling for the determination of time-weighted-average (TWA) concentration of formaldehyde in air is described. The sampling device was constructed by affixing an unbacked dimethyl silicone membrane to the base of a glass tube and by sealing the top with a rubber stopper. Formaldehyde permeates the membrane and reacts with 2-(hydroxymethyl)piperidine (2-HMP) coated on the surface of XAD-2. Sampling times from 15 min to 8 hr have been used. The formaldehyde—oxazolidine produced is thermally desorbed and determined by a packed column gas chromatograph equipped with a flame ionization detector (FID). The response of the monitor is directly proportional to the external concentration of formaldehyde over the concentration range 0.050–100 ppm. The permeation constant (the slope of the permeation curve) of the membrane is 0.333 μg ppm −1. hr, and the detection limit of the method is 0.03 ppm for an 8-hr sampling period. Relative humidity (RH) (35–94%), temperature (0–82°) and storage period (0–25 days) do not affect the permeation process for sample collection. Moreover, potential chemical interferences, 10 ppm acetone or acrolein, respectively, have no detectable effect on the process. The method gives TWA concentration directly from the measurements, and the equipment is economical and convenient for personal or multi-location sample collections.

Improved HPLC methodology in occupational exposure studies on formaldehyde

This work describes an HPLC method for the determination of formaldehyde concentration in air. Traps containing 20–40 mesh silica gel coated with 2,4-dinitrophenylhydrazine (DNPH) are used. After aspiration of air the traps are eluted with methanol. The hydrazone formed is then separated on a C18 column using a mobile phase of methanolwater (50–50 v/v). The effluent is monitored with a UV detector at 365 nm. To calibrate and to compare this method with that of Niosh 2502 (traps coated with 2 benzylamino ethanol on Chromosorb 102), a mixing chamber that generated atmospheres of known concentration of formaldehyde was used.