Mean Formaldehyde Concentration Research Articles

Organoleptic quality and formaldehyde content of mackerel marketed in Dar es Salaam, Tanzania

BackgroundFish constitutes a nutritious food that deteriorates quickly when poorly preserved. Several biochemicals, including formaldehyde, accumulate naturally in the fish post-mortem. Apart from this natural formaldehyde, reports reveal the deliberate addition of formalin (37% formaldehyde solution) to the stored fish as a preservative. This is risky to consumers since formaldehyde is carcinogenic, genotoxic, and a potentiator of other carcinogens.AimThis study aimed to assess both the organoleptic quality and formaldehyde content of mackerels, the most consumed fish in Dar es Salaam, Tanzania.MethodsA total of 60 mackerel samples were conveniently and equally obtained from the local markets, street vendors, and supermarkets in five districts of the Dar es Salaam region. Organoleptic quality was evaluated based on organoleptic characteristics. Formaldehyde analysis was done by High-Performance Liquid Chromatography (HPLC). Analysis of variance was subsequently run to test the variation of formaldehyde content in mackerel by outlet type and district.ResultsAll analyzed mackerel samples had acceptable levels of organoleptic quality (2.46 ± 0.50) and a mean formaldehyde concentration of 10.89 ± 2.44 mg/kg. On average, the samples from supermarkets had the highest level of organoleptic quality (2.20 ± 0.21) but were also the most contaminated with formaldehyde (16.07 ± 4.68 mg/kg), while those from local markets were the least contaminated (3.91 ± 1.86 mg/kg) (p = 0.000). Moreover, 0% (n = 0), 20% (n = 4), and 35% (n = 7) of samples from local markets, street vendors, and supermarkets, respectively, had formaldehyde concentrations above 20 mg/kg, the previously estimated highest concentration for naturally formed formaldehyde in fish.ConclusionMackerels marketed in Dar es Salaam have acceptable organoleptic quality but are substantially contaminated with formaldehyde. Whether this is natural or artificial formaldehyde, our findings are inconclusive given the conflicting global standards. Nonetheless, the findings reveal the potential exposure of fish consumers to formaldehyde. Future research should explore the dynamics of the accumulation of natural formaldehyde in marketed fish and accurately assess the risk associated with the exposure of consumers to the formaldehyde in fish. The emanating findings will ultimately guide the development of local guidelines for natural and permissible formaldehyde concentrations in fish and fish products in Tanzania.

Investigation of window-opening behaviour and indoor air quality in dwellings situated in the temperate zone in China

Indoor air quality (IAQ) is a key factor that could affect the indoor environment and people's health. In this study, we report a comprehensive study on IAQ in 30 dwellings in the temperate zone in China. Thirty naturally ventilated dwellings were selected in the urban area of Kunming, which is the largest city in temperate zone in China. In four seasons, short-term measurement of formaldehyde and benzene, toluene, xylenes-volatile organic compounds and air infiltration rate were conducted in these dwellings. A long-term 1-year monitoring of temperature, relative humidity, fine particulate matter (PM2.5), carbon dioxide (CO2), window-opening behaviour and night-time air change rate (ACR) were conducted in 13 of these dwellings by remote sensors. Short-term measurements showed the mean formaldehyde concentration in summer (100.76 μg/m3), benzene concentration in winter (8.46 µg/m3), PM2.5 concentration (80.4 µg/m3) in spring of 2017 exceeded the Chinese standard, the US Office of Environmental Health Hazard Assessment value and the World Health Organization guidelines. The night-time ACR was the highest in summer (2.1 h−1) and the lowest in winter (1.6 h−1) in bedrooms of 13 long-term monitored dwellings due to seasonal time variation in window opening in bedrooms, which was mainly driven by CO2 concentration, indoor temperature and outdoor PM10 concentration.

Indoor occurrence and health risk of formaldehyde, toluene, xylene and total volatile organic compounds derived from an extensive monitoring campaign in Harbin, a megacity of China

Human exposure to formaldehyde, toluene, xylene (FTX) and other volatile organic compounds (VOCs) are associated with negative health impact. To characterize the exposure and health effects of FTX and TVOC from indoor environments, we conducted an extensive monitoring campaign involving 1278 measurements of 472 indoor locations in Harbin, a megacity in China from May 2013 to March 2018. The results showed that household had the highest mean formaldehyde concentration (0.171 ± 0.084 mg m-3) among all types of indoor environments. Meanwhile, there was no significant differences in formaldehyde concentration of the living room, master bedroom, secondary bedroom and study room (p > 0.05), as well as toluene and xylene. The highest mean concentration of toluene, xylene and TVOC was measured in public bath center. Great difference was found between formaldehyde concentrations in 2013 and other years, except 2015. There were great positive nonlinear correlations between the indoor temperature and concentration of formaldehyde (p < 0.01), good negative nonlinear correlations between the finish time of decoration and concentration of formaldehyde (p < 0.01), good positive linear correlations between the relative humidity and concentration of formaldehyde (p < 0.01). A risk assessment methodology was utilized to evaluate the potential adverse health effects of the individual FTX compounds according to their carcinogenicities. The predicted carcinogenic risk of formaldehyde was greater than the threshold value 1E-06 at all environments. The non-carcinogenic risk of TX compounds in the population is negligible. For estimating human health risk exposure, sensitivity analysis showed that more attention should be given to the influential variables such as the level of pollutants.

Nasal cytology as a screening tool in formaldehyde-exposed workers.

Workers in pathology and anatomy laboratories may be exposed to formaldehyde. An evaluation of the early effects of this substance is, therefore, paramount. This preliminary study was conducted to evaluate if nasal cytology could be used as a tool to detect changes in nasal mucosa in workers exposed to formaldehyde. To assess whether nasal cytology was able to reveal any alteration of nasal mucosa in workers exposed to formaldehyde compared to unexposed subjects, and to ascertain whether a specific pattern of alterations correlated with years of exposure in order to evaluate long-term occupational exposure effects. The study included a group of workers exposed to formaldehyde and a group of non-exposed workers. All subjects underwent clinical examination, followed by nasal cytology. Pathological indices from each rhinocytograms were compared between the two groups. Nasal cytology revealed a chronic inflammatory non-allergic condition in the exposed group. Qualitative analysis of data distribution of neutrophils and mucous-secreting/ciliated cells ratio showed data clustering with a cut-off set at 15 years of exposure. The mean formaldehyde concentrations ranged from <0.04 to 0.15 parts per million (ppm). The maximum levels of formaldehyde concentrations ranged from 0.2 to 0.67 ppm. Our data indicate that nasal cytology may be a promising tool for the health surveillance of workers exposed to formaldehyde and may also represent a useful research tool for the study of the health effects of other chemicals irritants for the upper airways.

Investigation of the Pollution Level and Affecting Factors of Formaldehyde in Typical Public Places in Guangxi, China

ABSTRACTThis study focused on measuring the concentration of formaldehyde in furniture markets, malls, hotels, and restaurants in Guilin, Liuzhou, and Nanning in Guangxi China. Correlations between the indoor formaldehyde concentration and temperature, humidity, and air change rate were also obtained. The sixty sampled public places selected for this study represented the typical public indoor environment in Guangxi. The over standard rates of formaldehyde concentrations (0.1 mg m–3) measured in furniture markets, malls, and hotels were 94%, 87%, and 20%, respectively. The highest formaldehyde concentrations measured in furniture markets, malls, hotels and restaurants were 0.313 mg m–3, 0.231 mg m–3, 0.111 mg m–3, and 0.082 mg m–3. The overall mean formaldehyde concentrations in these four venues were found to be present in this descending order; furniture market (0.193 mg m–3) > mall (0.147 mg m–3) > hotel (0.079 mg m–3) > restaurant (0.058 mg m–3). This work showed that wood-related decorations and merchandises that contain high levels of formaldehyde, were the major sources of formaldehyde pollution in the indoor environment. Further analysis demonstrated that strong correlations (r > 0.80, p < 0.01) existed between the indoor formaldehyde concentration and temperature, humidity, and air change rate, which indicated that these indoor environmental factors appeared to be other key reasons for the high levels of indoor formaldehyde pollution. The results showed that a decrease in temperature and humidity, or an increase in air change rate in an indoor environment can effectively alleviate the level of indoor formaldehyde pollution. The findings of this study can further promote the development of measures to control indoor air pollution.

An assessment of formaldehyde emissions from laminate flooring manufactured in China

Formaldehyde emissions from two laminate flooring products, labeled as California Air Resources Board (CARB) compliant, were evaluated. Passive 24-hr samples (n = 79) and real-time measurements were collected following installation and removal of the products in two rooms of similar size. Mean formaldehyde concentrations following installation were 0.038 and 0.022 ppm for Products 1 and 2 respectively, and 7 days after flooring removal the concentrations returned to background pre-installation levels. Both products were also evaluated in a small chamber (ASTM D6007) using Deconstructive (de-laminated product) and Non-Deconstructive (intact product) methods. Deconstructive testing showed that Product 1 exceeded the applicable CARB emission standard by 4-fold, while Product 2 was equivalent to the standard. Non-Deconstructive measurements were far below the Deconstructive results and were used to predict 24-hr steady-state room air concentrations. Based on the products that we tested (one of which was found to not be compliant with the CARB standard), the airborne formaldehyde concentrations measured following installation in a real-world setting would not be expected to elicit adverse acute health effects.

Investigation of IAQ in Mechanically Ventilated Kindergartens and Elementary Schools in Korea

This study investigates the indoor pollutant levels in school buildings according to the operation of mechanical ventilation system. Three classrooms at two different elementary schools and four classrooms at two children's day care center in Korea were chosen for investigation of indoor air quality with mechanical ventilation systems. Measurements were conducted for particulate matter, formaldehyde, total volatile organic compounds, carbon monoxide, carbon dioxide, nitrogen dioxide, ozone, radon, and total bacteria counts. Differences in indoor pollutants concentrations with and without operation of ventilation systems in each classroom were analyzed. The results show that operation of ventilation systems could decrease the levels of indoor pollutants in the classrooms, especially showing the reduction of HCHO concentrations by 14.9-62.3%. representative samples in Singapore. This study reported that indoor CO 2 concentration levels were lower in Singapore child care centers when compared to child care centers from other cold climate countries due to the higher ventilation rate of child care centers in Singapore. St-Jean et al. (11) have assessed indoor air quality in 21 day care centers in Montreal, Canada and determined association between building characteristics and IAQ. They reported that over 85% of the day care centers had a mean CO 2 concentration higher than 1000 ppm. The mean formaldehyde concentration was 22.9 µg/m 3 . They also reported that the presence of a mechanical ventilation system and a large surface of play are per child were significantly associated with lower CO 2 levels. Chitra and Nagendra (4) have investigated indoor air quality parameters in a naturally ventilated school building located near an urban roadway in India. This study reported that the mean value of indoor PM 10 , PM 2.5 , PM 1 and CO concentrations were found to be 149 ± 69, 61 ± 29, 43 ± 24, 0.10 ± 0.18 and 95 ± 61, 32 ± 16, 18 ± 9 µg/m 3 , 0.11 ± 0.14 ppm, respectively for winter and summer seasons. Norback et al. (12) have studied the relationship between VOCs, respirable dust, and personal factors to prevalence and incidence of sick building syndrome in six primary schools. They reported that the average CO 2 concentrations in all sites were greater than 800 ppm and indicated inadequate ventilation. Lee and Chang (13) investigated IAQ of five classrooms in Hong Kong. This study showed that the average respirable suspended particulate matter (RSPM) concentrations were higher than the Hong Kong air quality objective (annual average, 55 µg/m 3

Formaldehyde concentrations in household air of asthma patients determined using colorimetric detector tubes

Formaldehyde is a colorless, pungent gas commonly found in homes and is a respiratory irritant, sensitizer, carcinogen, and asthma trigger. Typical household sources include plywood and particleboard, cleaners, cosmetics, pesticides, and others. Development of a fast and simple measurement technique could facilitate continued research on this important chemical. The goal of this research is to apply an inexpensive short-term measurement method to find correlations between formaldehyde sources and concentration, and formaldehyde concentration and asthma control. Formaldehyde was measured using 30-min grab samples in length-of-stain detector tubes in homes (n = 70) of asthmatics in the Boston, MA area. Clinical status and potential formaldehyde sources were determined. The geometric mean formaldehyde level was 35.1 ppb and ranged from 5 to 132 ppb. Based on one-way ANOVA, t-tests, and linear regression, predictors of log-transformed formaldehyde concentration included absolute humidity, season, and the presence of decorative laminates, fiberglass, or permanent press fabrics (P < 0.05), as well as temperature and household cleaner use (P < 0.10). The geometric mean formaldehyde concentration was 57% higher in homes of children with very poorly controlled asthma compared to homes of other asthmatic children (P = 0.078). This study provides a simple method for measuring household formaldehyde and suggests that exposure is related to poorly controlled asthma.

Occupational exposure to formaldehyde in an institute of morphology in Brazil: a comparison of area and personal sampling

Formaldehyde (FA) is a harmful chemical, which is classified as carcinogenic to humans (Group 1) by the International Agency for Research on Cancer. Solutions of FA that are used to preserve cadavers in research and education morphological institutes represent a risk to occupational health of professionals and students. During the dissection of cadavers in the anatomy laboratories, FA vapors are emitted, resulting in the exposure of students and their instructors to elevated levels of FA. The World Health Organization recommends an air quality guideline value of 0.1mgm(-3) for exposure to FA. The limit of occupational exposure adopted by the Brazilian legislation (2.3mgm(-3)) is markedly higher than those adopted by institutions of other countries around the world. The purpose of this study was to determine the levels of personal exposure and the area concentration of FA in the morphology department of the Federal Fluminense University, Brazil, and investigate and compare the relationship between them. Four rooms distributed in the three floors of the Morphology Department were evaluated: the embalming laboratory, the anatomy laboratories, the corridor of the teachers' rooms, and the entrance hall. Thirty-six samples in total were collected in the second semester of 2010 and first semester of 2011. The air sampling and FA analysis were performed according to the EPA TO-11A Protocol, using a diffusive sampling device for carbonyl compounds. Personal samples were collected from monitors using a sampling device pinned on each person's lapel. The samples were analyzed using rapid resolution liquid chromatography with UV-DAD detection at 360nm. The concentrations of FA ranged from 0.20 and 0.18mgm(-3) in the corridor between the teachers' rooms, 0.03 to 0.37mgm(-3) in the entrance hall, 0.22 to 2.07mgm(-3) in the anatomy laboratory, 2.21 to 2.52mgm(-3), in the embalming room. The levels found in the corridor between the teachers' rooms and in the entrance hall were lower than in other compartments because of their large distances to the sources of FA and better ventilation. The other rooms presented higher levels of FA because of the activities carried there (embalming and dissection procedures). Even in the rooms that showed the lowest levels of FA, the values found were higher than those established by all international guideline limits, except the Brazilian legislation limit, although, the concentration level in the embalming room was even greater than the Brazilian guideline. These concentrations are 100-1,000-fold higher than those reported in an FA outdoor study. The exposure levels of monitors and students ranged from 1.89 to 4.82mgm(-3), indicating that current practices at the Morphology Department at the university would represent a health risk. The simultaneous monitoring of area concentrations and personal exposure showed that the characteristics of classes and of cadavers' parts, the number of students in the room and even the activities of the monitors influence the FA concentrations. This study revealed that the concentration of FA was low in the ventilated areas of the Morphology Department, and that the personal exposure when the person was close to the cadavers during the dissection procedure was higher than the mean FA concentration. This should be considered in the risk assessment of FA during these activities without effective protection equipment. It is suggested that the Brazilian legislation of exposure to formaldehyde requires an urgent update considering international legislation.

Local ventilation system successfully reduced formaldehyde exposure during gross anatomy dissection classes

Dear Editor, In the recent Acta Anatomica Nipponica (Kaibogaku Zasshi Vol. 85, No. 1, 2010)—a special issue concerning the improvement of the formaldehyde (FA) environment in gross-anatomy laboratories—four papers were published, two of which described originally developed dissection tables equipped with local ventilation systems (Shinoda and Oba 2010; Kikuta et al. 2010) and two of which outlined the environmental health hazards caused by FA (Uchiyama 2010; Sakamoto and Miyake 2010). Due to its effectiveness and low cost, the FA solution is widely used in Japanese medical and dental schools to embalm human bodies donated for use in gross anatomy dissection classes. However, the gaseous FA that evaporates from embalmed bodies causes not only acute irritation to the eyes and respiratory tract but also chronic non-threshold carcinogenicity. According to a risk-based evaluation of FA, the Ministry of Health, Labor, and Welfare in Japan has set the administrative level of FA to 0.1 ppm in working environments in which FA is handled. In our medical school, the dissection laboratory for students (L23 9 W12 9 H3.3 m, in which 20–23 bodies prepared with 10 l of 5.5% FA/30% ethanol solution are used) had a high-performance general (whole-room) ventilation system with a competence of 25000 m/h; however, the mean FA concentration of the room (‘‘A’’ measurement) and the estimated maximum exposure to FA (‘‘B’’ measurement) during dissection classes were 0.520 and 0.480 ppm, respectively (HPLC analysis performed by Panasonic Health Organization Science Center of Industrial Hygiene, Osaka, Japan). To reduce FA exposure during dissection classes, we introduced 23 dissection tables with local ventilation apparatus (Meiko Medical, Fukuoka, Japan). The details of this system have already been described elsewhere (Shinoda and Oba 2010). Briefly, the system consists of a simple plenum-chambered dissection table and a transparent vinyl duct which connects the table to the pre-existing general ventilation duct via a flow control valve in the ceiling. The 40 pre-existing, randomly oriented air-supply openings in the ceiling were not replaced (no downward flow of air for each dissecting table). The total ventilation flow rate was 18 m/min/table. The local ventilation system we introduced successfully reduced the FA concentration of the room during dissection classes. The A and B FA measurements were 0.035 and 0.054 ppm, respectively. Using a photoelectronic method (FP-30, Rikenkeiki, Tokyo, Japan), we also measured the 30-min mean FA concentration at the center of the dissection room (1.2 m above the floor) and at the corner of a dissection table (0.5 m above the table) in every class 30–60 min after the start of the dissection (Fig. 1). The mean FA concentrations at the center of the room and the corner of the table were 0.056 (n = 41) and 0.057 ppm (n = 41), respectively. FA concentrations higher than 0.1 ppm were recorded for dissection schedules #8 and 9, during which the upper extremities were placed in the abducent position; thus, the source of the FA was out of the effective range of the local ventilation system. Thirty-nine of the 41 measurements of FA concentration at the center of the room and 40 of the 41 measurements at the corner of M. Takahashi M. Abe T. Yamagishi K. Nakatani Y. Nakajima (&) Anatomy and Cell Biology, Graduate School of Medicine, Osaka City University, 1-4-3 Asahimachi, Abeno-ku, Osaka 545-8585, Japan e-mail: yuji@med.osaka-cu.ac.jp

Human Cancer Risk from the Inhalation of Formaldehyde in Different Indoor Environments in Guiyang City, China

This study was conducted to estimate the risk of human cancer from the inhalation of formaldehyde in different indoor environments in Guiyang City in China. Offices had the highest mean formaldehyde concentration (0.11 mg/m(3)) and classrooms had the lowest mean formaldehyde concentration (0.04 mg/m(3)). The cancer risk levels in different indoor environments ranged from 6.96 x 10(-6 )to 2.48 x 10(-4) and were greater than the acceptable cancer risk 1 x 10(-6). High human formaldehyde risks imply a critical influence on human health in Guiyang City. The highest cancer risk values occurred in bedrooms (ranging from 1.87 in 10,000 to 2.48 in 10,000). For office workers, offices were the highest risk environment after bedrooms where formaldehyde concentration levels were identified. Students were the most sensitive population, and the highest priority should be given to protecting their health in indoor environments. Regulations and standards for low emission materials and public education in relation to indoor pollution are highly recommended in China to protect human health.

Formaldehyde Concentrations in Ambient Air in Urban and Rural Areas in Gunma Prefecture, Japan

We measured formaldehyde concentrations in ambient air at urban (Isesaki) and rural (Annaka) sites in Gunma Prefecture, Japan from June 1998 to March 2003. Measurements were carried out once in a month to obtain daily mean formaldehyde concentrations. At both the sites, mean concentrations of formaldehyde were significantly higher from April to September (summer) than from October to March (winter). Formaldehyde concentrations in Annaka were essentially as high as those in Isesaki in summer, but were significantly lower in winter. At both the sites, concentrations of formaldehyde and oxidants correlated significantly with one another in the summer; correlation coefficients in Annaka and Isesaki were 0.82 and 0.64, respectively. The fraction of formaldehyde formed photochemically based on concentrations of benzene was calculated to be as high as 80% in both the sites in summer. The results suggested that formaldehyde concentrations were high even in rural air, reflecting photochemical reactions rather than automobile exhaust.

Exposure to formaldehyde during an anatomy dissecting course

Formaldehyde is a flammable, colorless and readily polymerized gas at ambient temperature, and is one of the major pollutants in indoor air. Medical students during their dissection course are exposed to formaldehyde, whose exposure is recently considered to be one of the causes of multiple chemical sensitivity. To understand the system that produces exposures and to plan for implementing control options, this study examined formaldehyde exposures that occurred in the gross anatomy laboratory. Formaldehyde in air was sampled by an active 2,4-dinitrophenylhydrazine (DNPH)-silica gel cartridge, extracted with acetonitrile and analyzed with an high performance liquid chromatograph-ultraviolet(HPLC-UV)detector. The geometric mean formaldehyde concentration was 20-93 ppb in the anatomy laboratory before starting the anatomy dissecting. After beginning the dissecting, however, the highest geometric mean concentrations were 1012-1380 ppb. Significant differences were observed during the exposed period for symptoms of "unusual thirst", "burning eyes", "itchy eyes", "bad feeling", "fatigue", etc. in comparison with the non-exposed period. These results show that medical schools should take more concrete measures to reduce exposure to formaldehyde.

Indoor environmental quality in six commercial office buildings in the midwest United States.

The aims of this study were to characterize physical, mechanical, and environmental factors influencing indoor environmental quality (IEQ) in commercial office buildings; document occupant perceptions and psychosocial attributes; and evaluate relationships among these parameters. Six large office buildings in metropolitan areas were selected in Iowa, Minnesota, and Nebraska. Comprehensive sampling was conducted over one week in each building, during all four seasons. This paper presents the study methods and selected results from the first round of sampling (November 1996 to April 1997). Air flow and recirculation rates were quite variable, with the proportion of outdoor air provided to occupants ranging from 10 to 79 CFM/person. Carbon dioxide, carbon monoxide, and temperature were within ranges anticipated for nonproblem buildings. Relative humidity was low, ranging from 11.7 to 24.0 percent. Indoor geometric mean concentrations of total volatile organic compounds (TVOCs) ranged from 73 to 235 microg/m3. The most prevalent compounds included xylene, toluene, 2-propanol, limonene, and heptane. Geometric mean formaldehyde concentrations ranged from 1.7 to 13.3 microg/m3, and mean acetaldehyde levels ranged from <3.0 to 7.5 microg/m3. Airborne concentrations of culturable bacteria and fungi were low, with no samples exceeding 150 CFU/m3. Total (direct count) bioaerosols were more variable, ranging from 5010 to 10,700 organisms/m3. Geometric mean endotoxin concentrations ranged from 0.5 to 3.0 EU/m3. Respirable particulates (PM10) were low (14 to 36 microg/m3). Noise levels ranged from 48 to 56 dBA, with mean light values ranging from 200 to 420 lux. Environmental parameters were significantly correlated with each other. The prevalence of upper respiratory symptoms (dry eyes, runny nose), central nervous system symptoms (headache, irritability), and musculoskeletal symptoms (pain/stiffness in shoulders/neck) were elevated compared to other studies using similar questionnaires. Importantly, psychosocial factors were significantly related to increased symptoms in females, while environmental factors were more closely correlated with symptoms in males. Endotoxin concentrations were associated with symptoms in both males and females. These data will help to identify and quantify the relative role of factors that contribute to sick building syndrome. The data collected in this study may also be used to evaluate the effectiveness of current building operation practices, and can be used to prioritize allocations of resources for reduction of risk associated with IEQ complaints.

Formaldehyde in rainwater at Trombay, Mumbai: a coastal site in India

Formaldehyde was measured in rainwater samples collected at a residential area of Trombay, Mumbai (a coastal site in India). A mean concentration of 2.1 µmo1/1 and a range of 0.4-11.0 µmol/l were observed. The mean formaldehyde concentration in rainwater has increased from 1.2 µmol/l in 1979 by a factor of about two at this site.

Indoor and outdoor formaldehyde concentrations in homes in residential areas in Greater Cairo.

Indoor and outdoor measurements of formaldehyde were conducted at seven flats located in residential areas in Greater Cairo, during spring and summer seasons 1999. The mean daytime formaldehyde concentrations in kitchens, bedrooms and living rooms were 89, 100 and 100 ppb, respectively, in the seven flats. Significant positive correlations were found between the concentrations of formaldehyde found in these three rooms. On the other hand, no significant differences were found between the mean formaldehyde concentrations in these three rooms. The maximum mean concentration of formaldehyde (147 ppb) was recorded in a new flat, while the minimum concentration (43 ppb) was observed in an old flat. The maximum hourly and daytime concentrations were 350 and 225 ppb, respectively. Air temperature, relative humidity and the age of the flat are factors affecting the emission and concentration of formaldehyde. The maximum indoor and outdoor formaldehyde concentrations were recorded during the summer season. During the spring, 38% of the samples indicated that the concentration of formaldehyde in the seven flats exceeded 0.1 ppm, the American Society of Heating, Refrigerating, and Air Conditioning Engineers' (ASHRAE) standard; in the summer, this figure increased to 53%.

Appropriate Sampling Strategies for the Measurement of Formaldehyde in Indoor Air

Active and passive sampling methods are available for the determination of maximum formaldehyde concentrations and average formaldehyde concentrations respectively. The present work compares the performance of an active cartridge type sampler with an impinger method and a diffusive monitor which have previously been used at the Building Research Establishment. Good agreement between the three methods was found in a comparison at two formaldehyde concentration levels. The sampling strategy required to obtain a representative reading of the formaldehyde concentration in an indoor atmosphere was investigated using a commercially available diffusive sampler. An investigation of spatial variation in five rooms suggests that sampling in one location should give a representative reading of the formaldehyde concentration in a room, providing the sampler is not placed near a major source of formaldehyde. An initial investigation of temporal variation in six rooms found that one three day sampling period was sufficient to obtain a representative reading of the mean monthly formaldehyde concentration. Between month variation was found to be higher than within month variation although no strong seasonal effects were observed. The results suggest that more than one three day sampling period should be used to estimate the annual mean formaldehyde concentration and two measurements (summer and winter) may be a reasonable approach. Further work in a larger number of homes is in hand to verify the effectiveness of this sampling strategy.

Solvent and Formaldehyde Exposure in Parquet and Carpet Work

Abstract Hazardous, solvent-containing products are still widely used in carpet and parquet work. In this study, exposure of Finnish parquet and carpet workers to solvents was monitored. In addition, formaldehyde concentrations were measured during varnishing work. Three carpet and three parquet firms participated in the study. The measurements were carried out at 13 construction sites during 16 working days. In parquet work, the highest solvent concentrations were measured during puttying and undercoat varnishing. Mean additive concentrations of solvents were 6.5 to 7.3 times higher than the limit value, compared to the American Conference of Governmental Industrial Hygienists Threshold Limit Values 1988–89. For coating parquetry with a urea-formaldehyde-based varnish, the additive concentration of solvents was 3.3 times that recommended, and the mean formaldehyde concentration was 4.3 ppm. Dispersion adhesives used for installing parquetry and carpets did not emit solvent vapors in considerable amounts. However, using contact and synthetic resin adhesives in rooms with poor ventilation resulted in an additive concentration of solvents that was 3–5 times the amount recommended. Exposure of carpet and parquet fitters to solvents can best be reduced By changing from solvent-based products to water-based ones. High solvent concentrations can also be reduced by introducing more effective ventilation and improving upon the use of respirators.

Determination of in vivo concentration-time profiles of chlorhexidine and noxythiolin bladder irrigations.

The in vivo concentration-time profiles of chlorhexidine and noxythiolin bladder irrigations were determined by utilizing high-performance liquid chromatography techniques following a once daily irrigation. A total of 14 chlorhexidine irrigations established a mean concentration of 0.006% w/v, 2-3 h post irrigation. A total of 12 noxythiolin irrigations established a mean concentration of 0.266% w/v, 2-3 h post irrigation, which correlated to a mean formaldehyde concentration of 0.0119% w/v at 2-3 h, as estimated from N-methylthiourea. For both solutions the minimum inhibitory concentration was exceeded for up to 5 h post irrigation, which is sufficient contact time to establish a total kill, thus indicating the possibility that a once daily irrigation may be appropriate in asymptomatic bacteriuria which utilizes either chlorhexidine or noxythiolin.

Formaldehyde exposure in nonoccupational environments.

Free formaldehyde may be released from wood products and foam insulation where urea-formaldehyde resins have been used. From January, 1978 to November, 1979, 100 structures were investigated by the Wisconsin Division of Health after receiving complaints of health problems from occupants. Air samples were collected in midget impingers and analyzed for formaldehyde content by the chromotropic acid procedure. Health information was obtained from the occupants via questionnaires. Mean formaldehyde concentration observed ranged from below the limit of detection to 3.68 ppm. Eye irritation, burning eyes, runny nose, dry or sore throat, headache, and cough were the primary symptoms which were reported by the occupants. Statistically significant associations were seen between formaldehyde levels and age of home/building materials. Observations presented suggest nonoccupational, indoor environmental exposure to formaldehyde is significant and may reach levels which exceed occupational exposure standards.