Occupational exposure to volatile organic compounds and mitigation by push-pull local exhaust ventilation in printing plants

The extensive use of multiple organic solvents in offset lithographic printing causing high emissions of volatile organic compounds (VOCs) indeed poses a serious risk to printing workers' health. In this study, indoor air quality (IAQ) assessments were carried out in seven printing plants and the main objectives were to understand the effect of VOC emissions on IAQ and develop effective mitigation measures to protect workers. The thorough gas chromatography/mass spectrometry (GC/MS) measurements showed that although a variety of VOCs were presented in the indoor air, none of them was found close to individual 8-h time-weighted average (TWA) of the occupational exposure limit (OEL). The additive effect was also found below the critical value of unity. However, short-term personal exposure to total volatile organic compounds (TVOCs) was exceedingly high when a print worker carried out blanket and ink roller cleaning procedures. Therefore, the occupational health risk was mainly due to repeated short-term exposures during intermittent VOC-emitting procedures rather than long-term exposure to background VOCs. Push-pull local exhaust ventilation (LEV) was identified as an effective mitigation measure. Computational fluid dynamics (CFD) analysis was conducted to study the push-pull LEV operation. It was found that there existed a threshold LEV air flow rate for an abrupt reduction in the worker's exposure to VOCs. The reduction was less sensitive when the LEV airflow was further increased beyond the threshold. These phenomena, consistent with experimental results reported by other investigators, were explained by detailed CFD analysis showing the competition between the general ventilation and the push-pull LEV to become the dominating driving force for the resultant local flow pattern.     

Indoor air exposure to volatile compounds emitted by paints: experiment and model

To describe the evaporation of organic solvents from paints and the resulting indoor concentrations, a mathematical model and an indoor paint experiment are presented. The model describes painting in terms of an increasing area of paint during application and two compartments of paint once applied. Evaporation of organic solvents is driven by the vapor pressure of the organic solvent. The experiment revealed concentrations of n-alkanes in indoor air, during painting, and 3 days thereafter. To compare experimental results to model predictions, model parameters were measured at the start of the experiment. Diffusional exchange between paint compartments and fraction of paint applied to the upper compartment were set by expert judgment. Model predictions and experimental results were in agreement, although the timing of the concentration peak appeared difficult to predict.     

Ocular symptoms, tear film stability, nasal patency, and biomarkers in nasal lavage in indoor painters in relation to emissions from water-based paint

Purpose  

Despite the decreased use of solvent-based paint (SBP) and increased use of water-based paints (WBP) with possible risk for microbial growth, few health studies are available. The aim was to study the symptoms and ocular and nasal biomarkers in house painters in relation to paint use and personal exposure to volatile organic compounds (VOC) and microbial VOC (MVOC) during indoor painting with WBP.     

Development of solvent exposure index for construction painters

This article describes methodological approaches for reconstructing long-term occupational exposure to organic solvents among construction painters. A detailed exposure questionnaire was administered to 125 painters to develop a job exposure matrix (JEM). The questionnaire inquired about painting activities with solvent-based paints and use of protection equipment for the previous 25 years in 5-year intervals. Current and historical distributions of solvent air concentrations were assessed for the same time period based on the following information: industrial hygiene measurements, paint composition changes, and VOC emission rate changes from architectural and industrial maintenance coatings. Changes in protection factors of respirators were also assessed. A cumulative solvent exposure index was calculated for each painter through Monte Carlo simulations by combining appropriate input distributions of solvent air concentrations and protection factors of respirators with JEM. Sensitivity simulations revealed that the historical variations in solvent air concentrations had a higher impact on the cumulative solvent exposure index than changes in protection factors for respirators. Fifty-eight percent of painters were classified with a different exposure quartile when the solvent exposure index was used vs. an exposure based only on years using solvent-based paints, suggesting the need for more detailed exposure analysis than just years working when conducting epidemiologic studies for this worker population.     

Occupational exposure to nitrous oxide - the role of scavenging and ventilation systems in reducing the exposure level in operating rooms

OBJECTIVES: The aim of this study was to assess the level of occupational exposure to nitrous oxide (N(2)O) in operating rooms (ORs), as related to different ventilation and scavenging systems used to remove waste anaesthetic gases from the work environment. METHODS: The monitoring of N(2)O in the air covered 35 ORs in 10 hospitals equipped with different systems for ventilation and anaesthetic scavenging. The examined systems included: natural ventilation with supplementary fresh air provided by a pressure ventilation system (up to 6 air changes/h); pressure and exhaust ventilation systems equipped with ventilation units supplying fresh air to and discharging contaminated air outside the working area (more than 10 air changes/h); complete air-conditioning system with laminar air flow (more than 15 air changes/h). The measurements were carried out during surgical procedures (general anaesthesia induced intravenously and maintained with inhaled N(2)O and sevofluran delivered through cuffed endotracheal tubes) with connected or disconnected air scavenging. Air was collected from the breathing zone of operating personnel continuously through the whole time of anaesthesia to Tedlar((R)) bags, and N(2)O concentrations in air samples were analyzed by adsorption gas chromatography/mass spectrometry. RESULTS: N(2)O levels in excess of the occupational exposure limit (OEL) value of 180mg/m(3) were registered in all ORs equipped with ventilation systems alone. The OEL value was exceeded several times in rooms with natural ventilation plus supplementary pressure ventilations and twice or less in those with pressure/exhaust ventilation systems or air conditioning. N(2)O levels below or within the OEL value were observed in rooms where the system of air conditioning or pressure/exhaust ventilation was combined with scavenging systems. Systems combining natural/pressure ventilation with scavenging were inadequate to maintain N(2)O concentration below the OEL value. CONCLUSION: Air conditioning and an efficient pressure/exhaust ventilation (above 12 air exchanges/h) together with efficient active scavenging systems are sufficient to sustain N(2)O exposure in ORs at levels below or within the OEL value of 180mg/m(3).     

Evaluation of individual exposure to organic solvents using a portable VOC monitor]

Analysis by gas chromatograph after collection of personal samples is the most common method of evaluating individuals' exposures to organic solvents. This method provides us time-weighted averages (TWA) only, and does not measure fluctuating concentrations of organic solvents. A portable VOC monitor is widely used as a rapid screening instrument for volatile organic compounds (VOCs) in houses, schools, etc. The VOC monitor equipped with a photoionization detector can measure real-time concentrations of VOCs. In this study, the author investigated whether the VOC monitor can evaluate individuals' exposures to organic solvents. First, standard organic solvent gases were prepared and the gas concentrations were measured by a passive air sampler and the VOC monitor. Correction factors (CF) were obtained for the response of the isobutylene calibrated VOC monitor to equal concentrations of the organic solvents. Methyl ethyl ketone's CF was 0.5952, toluene's CF was 0.4418, and N,N-dimethylformamide's CF was 0.9017. Then, a mixed standard organic solvents gas was prepared and the gas concentration was measured by both methods. A significant correlation between both methods was obtained (p < 0.001). Subsequently, 37 male workers in a synthetic-leather factory were examined for solvent exposure using both the VOC and a passive sampler, Similar results were obtained by both methods (p < 0.001). Real-time data can be obtained using the VOC monitor and high exposure tasks can be identified. The VOC monitor will be useful for reducing occupational exposure. Since the VOC monitor provides detailed data of individuals' exposures to organic solvents.     

Volatile organic compounds, respirable dust, and personal factors related to prevalence and incidence of sick building syndrome in primary schools

Possible relations between incidence and prevalence of sick building syndrome (SBS), indoor exposures, and personal factors were studied in a four year longitudinal study among personnel (n = 129) in six primary schools. The mean concentration of carbon dioxide was above the recommended value of 0.08 microliter/l (800 ppm) in all schools, indicating a poor outdoor air supply. Indoor concentration of volatile hydrocarbon (VOC) was enhanced at high room temperatures. Respirable dust, but not concentration of VOC was enhanced at lower ventilation rates and high air humidity. Chronic SBS was related to VOC, previous wall to wall carpeting in the schools, hyper-reactivity, and psychosocial factors. Incidence of new SBS was related to concentration of respirable dust, current smoking, and the psychosocial climate. Remission of hyperreactivity, decrease in sick leave owing to airway illness, removal of carpeting in the schools, and moving from new to old dwellings resulted in a decrease in SBS score. It is concluded that SBS is of multifactorial origin, related to a variety of factors and exposures. The total concentration of hydrocarbons is a simple and convenient measure of exposure, which also seems to be a predictor of chronic symptoms. Further investigations on the effect of temperature, ventilation, and air humidity on SBS should consider how these factors may influence the chemical composition of the air. Because poor air quality in schools could also affect the children, it may have implications for the state of health of a large proportion of the population.     

Volatile organic compounds, respirable dust, and personal factors related to prevalence and incidence of sick building syndrome in primary schools.

Possible relations between incidence and prevalence of sick building syndrome (SBS), indoor exposures, and personal factors were studied in a four year longitudinal study among personnel (n = 129) in six primary schools. The mean concentration of carbon dioxide was above the recommended value of 0.08 microliter/l (800 ppm) in all schools, indicating a poor outdoor air supply. Indoor concentration of volatile hydrocarbon (VOC) was enhanced at high room temperatures. Respirable dust, but not concentration of VOC was enhanced at lower ventilation rates and high air humidity. Chronic SBS was related to VOC, previous wall to wall carpeting in the schools, hyper-reactivity, and psychosocial factors. Incidence of new SBS was related to concentration of respirable dust, current smoking, and the psychosocial climate. Remission of hyperreactivity, decrease in sick leave owing to airway illness, removal of carpeting in the schools, and moving from new to old dwellings resulted in a decrease in SBS score. It is concluded that SBS is of multifactorial origin, related to a variety of factors and exposures. The total concentration of hydrocarbons is a simple and convenient measure of exposure, which also seems to be a predictor of chronic symptoms. Further investigations on the effect of temperature, ventilation, and air humidity on SBS should consider how these factors may influence the chemical composition of the air. Because poor air quality in schools could also affect the children, it may have implications for the state of health of a large proportion of the population.     

Emission of volatile and semivolatile organic compounds from water-based akrylate paints

Identification and testing of organic compounds emissions from water-based akrylate paints were conducted. TD-GC/MS system was applied for identification of compounds. Emission was monitored in an environmental chamber with controlled temperature, relative humidity, and air exchange. Quantitative analysis was measured by GC method. Emission of main volatile organic compounds (VOC) semivolatile organic compounds (SVOC) and total volatile organic compounds (TVOC) were defined in various periods of time, within 30 days after paints application. The main organic compounds indicated high level of an initial emission after 24 hours. Some of water-based akrylate paints may release small quantities of SVOC (texanol) even 30 days after their application. It was demonstrated that the first-order emission decay model well describes the emission course from water-based paints.     

Assessing exposure to solvent vapour during the application of paints, etc.--model calculations versus common sense

Simple formulae expressing average and maximum concentrations of solvent vapour in indoor air during the application of paints, glues, and the like, have been derived using a six parameter mathematical exposure model MEM 1. The model is valid for solvents that evaporate from the liquid without fractionation and at a constant rate. Some features of the relation between exposure level and system parameters were found to be considerably more tricky than expected.     

Exposure assessment of non-electric ice resurfacer operators in indoor ice rinks: a pilot study

Exposure of ice resurfacer operators to indoor air contaminants was measured in six indoor ice arenas. A standardized questionnaire on technical and operational features was employed and indoor airborne concentrations of carbon monoxide (CO), carbon dioxide (CO₂), nitric oxide (NO), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), and total volatile organic compounds (VOCs) were measured. Air samples were collected using a range of direct reading instruments attached to the driver’s seat of the resurfacer. The range of mean exposure concentrations via positional sampling (i.e. as close as able to the operator’s breathing zone) were 5.7–7.4 ppm, 694–2171 ppm, <0.5 to 0.5 ppm, and < 0.1 to 0.2 ppm, for CO, CO₂, NO, and NO₂, respectively. Exposure levels for SO₂ and VOC were below detection. Overall, each of the measured indoor air contaminants was found to be below its respective occupational exposure limits (OEL), suggesting that the risk of hazardous exposure is low. The use of natural gas as a fuel source is believed to contribute to low contaminant concentrations.     

Inflammation markers in nasal lavage, and nasal symptoms in relation to relocation to a newly painted building: a longitudinal study

Introduction: There is a need to evaluate possible health effects of ventilation improvements and emissions from new buildings, in longitudinal studies. New methods to study biological effects on the eyes and upper airways are now available. Material and methods: A longitudinal study was performed on 83 trained social workers in two offices in Uppsala, Sweden. The exposed group (n= 57) moved to a newly redecorated building nearby. Low emitting building material had been used, including a new type of solvent-free water-based paint. The control group (n= 26) worked in the same office during the study period (November 1995 to February 1996). Hygiene management was carried out in both offices, at the beginning and the end of the investigation. Tear film stability (BUT) was measured. Nasal patency was measured by acoustic rhinometry, and eosinophilic cationic protein (ECP), myeloperoxidase (MPO), lysozyme and albumin were analyzed in nasal lavage fluid (NAL). Results: The relocation resulted in an increase in the personal outdoor airflow rate from 11 to 22 l/s. Indoor concentrations of terpenes were higher in the new building, and powdering of the new linoleum floor was observed. Measurements showed low levels of volatile organic compounds (VOC), formaldehyde, carbon dioxide (CO₂), nitrogen dioxide, respirable dust, and microorganisms in the air of all buildings. The move resulted in an increased nasal patency and an increase of ECP and lysozyme in NAL, after adjusting for changes in the control group. No changes were observed for nasal or ocular symptoms. A seasonal effect, with a decrease of ECP, was observed in the control group. Conclusion: A well-ventilated office building can be redecorated without any major ocular or nasal effects, or measurable increase of indoor air pollution if low-emitting building materials are selected. In agreement with previous evidence, the improved ventilation flow may explain the increase of nasal patency. The increase of ECP and lysozyme in NAL suggested an inflammatory effect in the new building. Since this building had increased ventilation flow, increased concentrations of terpenes, and powdering from the polish on the new linoleum floor, identification of causative agents was difficult. The hygiene measures did not give any evidence that emissions from the new type of solvent-free water-based paints or building dampness were responsible for the observed nasal effects. Considering the higher emissions of VOC reported from older types of water-based latex paints and solvent-based wall paints, the new type of solvent-free water-based paint seems to be a good choice from the hygiene point of view. Received: 21 December 1998 / Accepted: 20 June 1999     

Occupational exposure to water-based paints and self-reported asthma,lower airway symptoms,bronchial hyperresponsiveness,and lung function

The associations between occupational exposure to water-based paints and the prevalence of self-reported asthma, other lower airway symptoms, bronchial hyperresponsiveness (BHR), and lung function were studied in house painters. Symptom prevalences were obtained from a self-administered questionnaire sent to 415 male painters during 1989–1992. Clinical investigations were carried out in three selected groups: 23 painters with asthmatic symptoms, nine painters with other lower airway symptoms, and 12 painters without airway symptoms. The clinical studies included lung function test, methacholine provocation test, and occurrence of atopy, confirmed by skin prick test to common allergens. In addition, a group of 18 young male painters with no occupational exposure to solvent-based paints were followed with dynamic spirometry before and after a workshift, when only water-based paints were used. The prevalence of self-reported asthma (7%) was somewhat, but not statistically, increased compared to an industrial population without exposure to water-based paints or other airway irritants. A decrease in FEV₁ and FVC during the workday was observed in the young painters. In the clinical studies the painters exhibited increased BHR compared to the referents and a decreased FEV₁. The number of years working as a painter was related to a decrease in FEV₁, which was most pronounced in subjects with atopy who also reported lower airway symptoms in relation to the degree of work with water-based paints, but not to the degree of use of solvent-based paints. Our results indicate that house painters have an increased risk of airway problems. A contributory cause could be exposure to volatile organic compounds or other volatile compounds emitted from water-based paints. It is also concluded that painters with atopy should be informed about the increased risk of airway illness. This would be an important task for occupational health services in their aim of preventing the adverse effects of occupational exposures.     

Hearing loss among workers exposed to moderate concentrations of solvents.

OBJECTIVES: It is known that some industrial organic solvents are ototoxic. This study was aimed at evaluating the hearing effects of a mixture of organic solvents alone or in combination with noise on employees in paint and lacquer enterprises. The concentration of solvents was below the occupational exposure limits (OEL) for most of the subjects. METHODS: Altogether 517 subjects were divided into the following three groups: persons with no risk due to noise or organic solvent exposure at the workplace, workers exposed to organic solvents only, and workers exposed to both organic solvents and noise. RESULTS: The relative risk (RR) of hearing loss in the solvent-only exposure group was significantly increased (RR 4.4 and RR 2.8 for noise exposure of < 80 dB-A and < 85 dB-A, respectively) in a wide range of frequencies (2-8 kHz). No additional risk in the solvent + noise exposure group was found (RR 2.8). Hearing thresholds were significantly poorer in a wide range of frequencies (1-8 kHz) for both groups exposed to solvents, when compared with the reference group. The mean hearing thresholds at frequencies of 2-4 kHz were poorer for workers exposed to solvents + noise than for the solvent-only group; this finding suggests an additional effect for noise. However, there was no correlation between hearing loss and the extent of solvent exposure. CONCLUSIONS: The results indicate that occupational organic solvent exposure at moderate concentrations increases the risk of hearing loss, and the ototoxic effects should be considered when the health effects of exposed workers are monitored.     

Lead in housing paints: an exposure source still not taken seriously for children lead poisoning in China

After prohibitions on lead gasoline additives, which have proved to be a public health accomplishment world wide, many countries focus on other exposure source of children lead poisoning. Removing lead from paints is one of the important measures. Although there have been regulatory limits on lead in paints in China, evidence reported in this article indicates that lead-based paints were very common in new paints available for housing and in existing residential paints. Twenty-nine of 58 new paint samples (50%) had lead content equal to or exceeding 600 ppm, including 14 (24%) equal to or exceeding 5000 ppm. The highest sample contained 153,000 ppm lead, about 15% of the paint weight. Thirty-two new paints (55%) contained “soluble” lead exceeding 90 ppm, the current lead limit on paints in China. Of the existing paints, 16 of 28 samples of existing paint (57%) collected from 24 kindergartens and primary schools had lead concentrations equal to or exceeding 600 ppm, including six samples (21%) equal to or exceeding 5000 ppm. The highest concentration sample contained 51,800 ppm lead, accounting for 5.2% of the paint weight. It has been shown in many areas that paint lead is a major exposure source for lead poisoning in children. This is particularly true after the phasing out of lead from gasoline. Effective limitation on lead content in new paint, and lead hazard control measures directed towards existing paint, could reduce children blood lead levels (BLLs). There has been a lead standard for paints in China since 1986 and a stricter limit was introduced in recent years. Governments should take it seriously and enforce regulations, commit a long-term challenge to eliminate paint lead as it is the threat to current and the next generation.     

Lead levels in new enamel household paints from Asia, Africa and South America

In 2006 a report on the analysis for lead in 80 new residential paints from four countries in Asia revealed high levels in three of the countries (China, India and Malaysia) and low levels in a fourth country (Singapore) where a lead in paint regulation was enforced. The authors warned of the possible export of lead-painted consumer products to the United States and other countries and the dangers the lead paint represented to children in the countries where it was available for purchase. The need for a worldwide ban on the use of lead in paints was emphasized to prevent an increase in exposure and disease from this very preventable environmental source. Since the earlier paper almost 300 additional new paint samples have been collected from the four initial countries plus 8 additional countries, three from Asia, three from Africa and two from South America. During the intervening time period two million toys and other items imported into the United States were recalled because the lead content exceeded the United States standard. High lead paints were detected in all 12 countries. The average lead concentration by country ranged from 6988 (Singapore) to 31,960 ppm (Ecuador). One multinational company sold high lead paint in one country through January 2007 but sold low lead paint later in 2007 indicating that a major change to cease adding lead to their paints had occurred. However, the finding that almost one-third of the samples would meet the new United States standard for new paint of 90 ppm, suggests that the technology is already available in at least 11 of the 12 countries to produce low lead enamel paints for domestic use. The need remains urgent to establish effective worldwide controls to prevent the needless poisoning of millions of children from this preventable exposure.     

职业接触定量化定义探讨

目的比较化学物职业接触限值(OEL)与环境空气污染物浓度限值,探讨职业接触定量化的界定。方法搜集中国、美国、欧洲化学物OEL与环境空气污染物浓度限值,并进行统计分析。结果共收集到30种化学物的45对OEL和环境浓度限值。OEL和环境空气污染物浓度限值几何均数分别为2.09 mg/m3和0.01 mg/m3,OEL是环境空气污染物浓度限值的200.17倍。2限值回归方程为lgy=1.182 lgx-2.36[决定系数(R2)=0.567]。2限值概率密度函数曲线交点浓度值为0.092 9 mg/m3,是OEL的1/22.45,环境空气污染物浓度限值8.93倍。当浓度取1/20 OEL时,该浓度低于对应的环境空气污染物浓度限值比例为20%。结论当工作场所化学物浓度高于OEL 1/10时,可定义为职业接触。     

A healthy home environment?

Over the past seven years, the U.S. Environmental Protection Agency has consistently ranked indoor air pollution among the top five risks to public health. One of the most dangerous indoor air pollutants is carbon monoxide (CO). CO can be lethal, but perhaps more important, many people suffer ill health from chronic, often undetected exposure to low levels of this gas, resulting in fatigue, headache, dizziness, nausea, and vomiting. Another dangerous pollutant is volatile organic compounds (VOCs), which come from sources including building products, cleaning agents, and paints. One VOC, formaldehyde, can act as an irritant to the conjunctiva and upper and lower respiratory tract. Formaldehyde is also known to cause nasal cancer in test animals.     

房屋装修过程中室内空气污染物的动态变化

[目的]观察房屋装修过程中室内空气主要污染物的动态变化。[方法]选择一套装修中的普通民宅为观察对象,分别于装修前后不同阶段7次采集室内空气样本,采用分光光度法及气相色谱法分析样本,动态观察空气中甲醛、苯及苯系物、总挥发性有机物（TVOC）等污染物的浓度变化。[结果]参照《室内空气质量标准》（GB／T18883-2002）,房屋在常规装修过程中超标的主要污染物为二甲苯（为标准限值0．20mg／m^3的5．0—75．0倍）、TVOC（为标准限值0．60mg／m^3的12．0—79．0倍）和甲醛（为标准限值0．10mg／m^3的1．4—4．0倍）,其中二甲苯和TVOC主要来源于油漆稀释剂,甲醛主要来源于墙面乳胶漆以及家具板材所用胶黏剂;在时间上以油漆喷涂、乳胶漆滚涂以及家具进场后污染最为严重。[结论]室内装修过程中挥发性污染物超标严重,主要超标物质为二甲苯、TVOC和甲醛。污染物浓度值与通风状况、装修时间密切相关。监测结果表明,装修结束后通风5个月基本可使室内污染物浓度降低到标准限值之下。     

Occupational exposure during application and removal of antifouling paints

Exposure data on biocides are relatively rare in published literature, especially for secondary exposure. This is also the case for antifouling exposure. Therefore, a field study was carried out measuring exposure to antifouling paints. Both primary exposure (rolling and spraying) and secondary exposure (during sand blasting) were studied. Exposure during rolling was measured in boatyards where paints containing dichlofluanid (DCF) were applied. Spraying was measured in dockyards (larger than boatyards) where paints containing copper were applied. Furthermore, during sand blasting the removal of old paint layers containing copper was measured. A total of 54 datasets was collected, both for inhalation and dermal exposure data. For paint and stripped paint bulk analyses were performed. The following values are all arithmetic means of the datasets. Inhalation of copper amounted to 3 mg m-3 during spraying and to 0.8 mg m-3 during sand blasting. Potential body exposure loading amounted to 272 mg h-1 copper during spraying and 33 mg h-1 during sand blasting. For dichlofluanid the inhalation exposure loading was 0.14 mg m-3 during rolling, whereas the potential body exposure loading was 267 mg h-1 and potential hand exposure loading 277 mg h-1. The results for primary exposure compare well to the very few public data available. For the secondary exposure (sand blasting) no comparable data were available. The present study shows that the exposure loading should be considered more extensively, including applicable protective gear. In this light the findings for the potmen during sand blasting suggest that personal protective equipment should be (re)considered carefully.