Small bakeries--a cross-sectional study of respiratory symptoms, sensitization and dust exposure.

This cross-sectional study investigated the prevalence of respiratory symptoms and sensitization to dust components in 224 individuals in 18 small bakeries in Scotland. Each work practice in the bakeries was characterized by an assessment of dust exposure and assigned to a category with either a direct exposure to flour dust of an indirect exposure to flour dust. We found that work-related respiratory symptoms were significantly associated with specific IgE to wheat flour and amylase but not to exposure category (except for nasal/eye symptoms). However, specific IgE to wheat flour was significantly associated with exposure category. There was a higher prevalence of immunological sensitization, reporting of work-related respiratory symptoms and exposure to dust than in other studies and of the 144 personal dust sample results taken, 21 (14.6%) of the total exceeded 10 mg/m3, the substantial dust concentration as outlined by the COSHH Regulations. Follow-up of those with work-related asthma symptoms (questionnaire response) was inconclusive of the work-relatedness of their symptoms, although it did confirm respiratory morbidity.     

Respiratory symptoms and wheat flour exposure: a study of flour millers

The objective of this study was to determine the prevalence of respiratory symptoms and their relationship to sensitization to wheat flour allergens and fungal amylase, in a group of workers from the UK flour milling industry. A cross-sectional study was used to evaluate symptoms, using a structured interview technique, and sensitization, using skin prick test findings, from 679 employees in flour milling and packing operations at 18 flour mills. A total of 147 workers (147/679, 22%) described upper respiratory tract symptoms of some kind. In the majority (139/147, 95%) these symptoms were of an occasional or transitory nature and were related to short-term exposures to high levels of dust. Three individuals (3/679, 0.4%) were identified whose symptoms were thought to be the result of allergy to wheat flour. The prevalence of positive skin prick tests to wheat flour allergens and to fungal amylase was 1.2% (8/678) and 0.9% (6/678), respectively. Measurements of total inhalable dust exposure for personnel exposed to flour dust were taken at 10 of the sites (116 samples). For production personnel the levels were typically between 1 and 10 mg/m3 (8-h time weighted average), with a median of 6.2 mg/m3. Hygiene operatives had appreciably higher exposure than production personnel, with a median of 18.7 mg/m3. Overall, 43% (50/116) of all samples exceeded 10 mg/m3 (8-h time weighted average). The findings suggest that the risk of sensitization to wheat flour allergens from current dust exposures in flour mills is very low. Wheat allergy was responsible in only a small proportion of the total who had respiratory symptoms. The principal causation of symptoms experienced by the workforce was considered to be a non-specific irritant effect related to short-term exposures to high levels of total inhalable dust.     

Wood dust exposure during furniture manufacture--results from an Australian survey and considerations for threshold limit value development.

A survey of time-weighted average (TWA) personal inhalable dust exposures for woodworkers in 15 Australian furniture factories was undertaken. There was significant variation in the individual dust measurements with mean exposures of 3.2, 5.2, and 3.5 mg/m3 for wood machinists, cabinetmakers, and chair framemakers, respectively. Hardwoods, softwoods, and reconstituted woods are used in the industry, but only minor differences in mean exposures or particle size distributions were found for the broad categories. In addition, a modified British Medical Research Council respiratory questionnaire was used to obtain information about work-related symptoms and job activities. Compared with a control group, the woodworkers reported more eye, ear, and nasal problems, with the differences being statistically significant. However, among the woodworkers themselves, with the exception of several nasal symptoms, the prevalences of reported symptoms were poorly correlated with gravimetric measurements of personal dust exposure. The problem of selection bias in cross-sectional studies is discussed. For a mean TWA personal exposure of about 3 mg/m3, hardwood users were more likely to report nasal symptoms than users of reconstituted wood. The question of appropriate exposure standards for woods in general is addressed by reference to those important health effects, besides sino-nasal cancer, that have been investigated. Further exposure guidelines should be formulated for groups of woods that are known to cause a common health effect, such as nasal/respiratory sensitization.     

Respiratory disorders and allergies in tea packers.

The aim of this study was to determine whether respiratory symptoms or cross-shift declines in lung function were related to occupational exposure to tea dust. A cross-sectional epidemiological study was conducted at a tea-packing plant. Subjects completed a questionnaire, spirometry before and after a full work shift, skin prick testing and venipuncture. Among the 83% of the workers at the site who participated, the prevalences of asthma, wheezing, hay fever and atopy were similar to the general population. Work-related nasal symptoms were more commonly reported by blenders and operators. There were six (3.2%) subjects with a cross-shift decline in the forced expiratory volume in 1 s of > 10%. Specific immunoglobulin E antibodies to black or chamomile tea were observed in 10 (5.6%) employees. As there was little evidence of specific allergic sensitization to the tea varieties tested, the excess of work-related respiratory and nasal symptoms probably represented non-specific irritation.     

Respiratory response to endotoxin and dust predicts evidence of inflammatory response in volunteers in a swine barn

BACKGROUND: It has been shown that exposure in intense exposure in swine barn facilities is associated with increased respiratory symptoms and reduction in pulmonary functions. This study investigated if systemic response could be predicted by FEV(1) response following swine barn exposure. METHODS: Na?ve males were tested at baseline, low and high endotoxin and dust levels. Subjects were classified as "more responsive" (n = 9) or "less responsive" (n = 11) based on FEV(1) reduction following high endotoxin exposure. Health measures included pulmonary function testing, blood samples and nasal lavage. Environmental samples were collected from the barn. RESULTS: White blood cells and blood lymphocytes at low exposure were significantly greater in those who were "more responsive" compared to those who were "less responsive". There was a significant increase in blood lymphocytes, serum IL6, total nasal lavage cells and nasal IL8 at high exposure among "more responsive" subjects compared to "less responsive" subjects. CONCLUSIONS: Respiratory response to high-level endotoxin and dust exposure predicts evidence of inflammatory response throughout a range of endotoxin and dust exposures.     

Health surveillance in milling, baking and other food manufacturing operations--five years' experience.

The objective of this study was to describe the incidence of allergic respiratory disease and its outcome in terms of symptoms and jobs, across different flour-using industries. It uses the findings of a health surveillance programme in a large food organization over a five-year period. The population under surveillance consisted of 3,450 employees with exposure to ingredient dusts, of whom 400 were in flour milling, 1,650 in bread baking, 550 in cake baking and 850 in other flour-using operations. A total of 66 employees with either asthma or rhinitis symptoms attributable to sensitization to allergens in the workplace were identified. The majority of these (48/66) had become symptomatic prior to the commencement of the health surveillance programme in 1993. The incidence rates (per million employees per year) for those who developed symptoms between 1993 and 1997 were 550 for flour milling, 1,940 for bread baking, 0 for cake baking and 235 for other flour-using operations. The agent believed to be responsible for symptoms was most commonly grain dust in flour millers and fungal amylase in bread bakers. Wheat flour appeared to have a weaker sensitizing potential than these other two substances. In terms of outcome, at follow-up 18% of symptomatically sensitized employees had left the company. Two of the ex-employees retired through ill health due to occupational asthma. Of those still in employment, 63% described an improvement in symptoms, 32% were unchanged and 4% were worse than when first diagnosed. Over half the cases still in employment were continuing to work in the same job as at the time of diagnosis.     

Respiratory symptoms and sensitization in bread and cake bakers

This purpose of this study was to examine the relationship betweenexposure to wheat flour, soya flour and fungal amylase and thedevelopment of work-related symptoms and sensitization in breadand cake bakery employees who have regular exposure to thesesubstances. The study populations consisted of 394 bread bakeryworkers and 77 cake bakery workers whose normal jobs involvedthe sieving, weighing and mixing of ingredients. The groupswere interviewed with the aim of identifying the prevalence,nature and pattern of any work-related respiratory symptoms.They were also skin-prick tested against the common bakery sensitizingagents, i.e., wheat flour, soya flour, rice flour and fungalamylase. The results of personal sampling for sieving, weighingand mixing operations at the bakeries from which the study groupswere taken were collated in order to determine typical exposuresto total inhalable dust from the ingredients, expressed as 8hour time-weighted average exposures. Data from the health surveillanceand collated dust measurements were compared with the aim ofestablishing an exposure-response relationship for sensitization.The prevalence of work-related symptoms in bread bakery andcake bakery ingredient handlers was 20.4% and 10.4% respectively.However, in a large proportion of those reporting symptoms inconnection with work, the symptoms were intermittent and ofshort duration. It is considered that the aetiology of suchsymptoms is likely to be due to a non-specific irritant effectof high total dust levels, rather than allergy. None of thecake bakers and only 3.1% of the bread bakers had symptoms whichwere thought to be due to allergy to baking ingredients. Usingskin-prick testing as a marker of sensitization, the prevalenceof positive tests to wheat flour was 6% for the bread bakersand 3% for the cake bakers. Comparable prevalences for soyaflour were 7% and 1 % respectively. However, the prevalenceof positive skin-prick tests to fungal amylase was 16% amongstthe bread baking group with only a single employee (1 %) inthe cake baking group having a positive test. Furthermore, thisemployee had previously worked in a bread bakery. The differencein rates of sensitization to wheat flour between the bread andcake bakers is not statistically significant, whereas the differencefor soya flour is at the borderline of statistical significance(p=0.045). In contrast, the difference in fungal amylase sensitizationis significant at the 0.1% level. For both bread and cake bakers,the 8 hour time-weighted average exposures for each of the activitiesshowed a wide variation with mixing having the lowest averageexposure and sieving the highest. Out of the allergens studiedin this investigation, fungal amylase is the principal sensitizerin large scale bread bakeries, with the main source of exposurebeing the handling of bread improvers. In contrast, the riskof sensitization to wheat flour is low in both bread and cakebakeries. The absence of positive skin-prick tests in the subgroupof cake bakery employees who regularly handle fungal-amylase-containingflour suggests that their levels of exposure are below the thresholdfor sensitization to amylase.     

Persistence of respiratory symptoms in ex-underground iron ore miners

AIMS: To assess the persistence of respiratory symptoms in ex-miners after cessation of mining exposure. METHODS: Population-based cross-sectional study using a postal questionnaire comparing prevalence of symptoms between ex-miners who had stopped mining at least 1 year before the study and referents not occupationally exposed to irritants or dust. Age, smoking and a family history of asthma were considered as possible confounders in the analysis. RESULTS: A total of 206 ex-miners and 4,560 referents participated. Ex-miners had on average been working as miners for 13 years and had stopped mining 16 years before the study. Chronic productive cough and physician-diagnosed chronic bronchitis were significantly more common among ex-miners (P < 0.05 and <0.01, respectively). Furthermore, there was a trend that other respiratory symptoms were more common in ex-miners. CONCLUSION: Ex-miners had an increased risk of chronic productive cough and physician-diagnosed chronic bronchitis many years after they had stopped working as a miner.     

Preventing baker's asthma: an alternative strategy

BACKGROUND: Although baker's asthma has attracted considerable research interest over the last 30 years, success in its prevention has been slow to achieve. This paper describes the results of an alternative preventive strategy, based on an observation that the excess of sensitization in bread bakers is largely due to IgE-mediated allergy to fungal amylase, contained in bread improvers. The practical application of the strategy has been to limit bread improver exposures to <1 mg/m3 [8 h time-weighted average (TWA)], whilst exposures to all other ingredients, including flour, have been limited to <10 mg/m3 (8 h TWA). METHOD: The paper describes the findings of in-house respiratory health surveillance and dust sampling programmes, from a UK food company whose primary interests are milling and baking, over the period following the introduction of the strategy to target the reduction in bread improver exposure. RESULTS: Over the 10 year period of surveillance, the incidence of symptomatic sensitization in the bread baking sector (2240 per million employees per annum) was greater than for the other flour-using groups (330 per million employees per annum), despite broadly similar total inhalable dust exposures. There was an overall reduction in the incidence of new cases of symptomatic sensitization, from 2085 per million employees per year in the first 5 years of the surveillance programme, to 405 per million employees per year in the subsequent 5 years. CONCLUSION: The strategy of targeting bread improver exposure is an effective approach for the prevention of new cases of symptomatic sensitization in bread bakeries.     

Challenge testing in the diagnosis of occupational allergic conjunctivitis

BACKGROUND: Providing evidence for the allergic aetiology of ocular symptoms developing as a result of occupational exposure is important for compensation procedures in many countries. AIM: To perform cellular analysis of tear fluid before and after a specific challenge test with high-molecular weight allergens in symptomatic subjects. METHODS: The subjects were 23 bakers with a history of conjunctivitis or rhinoconjunctivitis associated with occupational exposure to wheat flour and positive skin prick test with this allergen. A specific inhalation challenge test with wheat flour and a placebo test were performed. The symptom score (SS) and cellular changes in tear fluid and nasal washings were assessed. RESULTS: Specific provocation test induced significant eosinophil influx in tear fluid in only six patients. No changes in the proportion of other cells could be observed. Cytological changes in tear fluid did not correlate with either ocular SS (Pearson r = 0.18, P = 0.40) or changes in the nasal lavage fluid or SS (Pearson r = 0.13, P = 0.56). However, an analysis of SS results obtained at 30 min and at 24 h after the challenge revealed that cellular changes in tear fluid correlated significantly both with the early and late changes in SS (Pearson r = 0.52, P < 0.05 and Pearson r = 0.81, P < 0.001, respectively). CONCLUSIONS: Analysis of cellular changes in tear fluid during specific inhalation challenge test seems to be a valuable diagnostic tool in occupational ocular allergy. However, the discrepancy between the findings of cellular analysis and SS revealed by the present study requires further research.     

Nasal septal ulceration and perforation in jiggers

The paper describes two cases of occupational ill-health inindividuals working as jiggers in the chromium electroplatingindustry. Much has been written about the effects of chromicacid on the platers who may work directly over the plating baths,but a literature search failed to identify any reports of ill-healthin those who work alongside platers preparing the items to beplaced into the baths. One case of nasal ulceration and oneof nasal septal perforation are described. Reference is madeto the role of the ‘responsible person’ in healthsurveillance for such workers to allow early identificationof occupationally acquired ill-health and prevention of furthercases.     

Across-shift lung function variation in cottonseed oil workers

BACKGROUND: The effects of cotton dust on pulmonary function among workers employed in cotton-spinning mills are well known. However, little data exist on the prevalence of this disorder in 'non-textile' cotton industries, including cottonseed oil mills, where high levels of exposure to dust have been demonstrated. AIMS: This study was performed in order to determine the across-shift and across-week decline of FEV(1) and respiratory symptoms among workers in a cottonseed oil mill. METHODS: Sixty-six exposed and 48 unexposed workers of a cottonseed oil mill in Turkey were investigated by questionnaire and lung function test (LFT). LFTs were performed before and after shift on all the working days of the week. Acute airway response was defined as an across-shift decline in FEV(1) of 5% or more on the first working day. RESULTS: Smoking was the only risk factor for having respiratory symptoms. Acute airway response was more frequently observed in the exposed group as compared to the unexposed group (OR = 6.2, 95% CI = 2.3-16.7). The median across-shift decline in FEV(1) on the first day (120 ml) significantly improved on the following days (10, 50, 60 and -30 ml). CONCLUSION: Smoking appears to be the main risk factor for having respiratory symptoms. Cottonseed dust may cause an acute pulmonary function decline on the first working day, but not on the following days of the week. This decline is associated with respiratory symptoms in exposed workers.     

Ventilatory function of factory workers exposed to tea dust

A cross-sectional study was conducted in order to determinethe prevalence of respiratory symptoms and the effect on ventilatorycapacity in workers exposed to tea dust for at least five yearsduring the sifting process of tea manufacture compared to acontrol group of field workers who were not exposed to tea dustpreviously. Fifty-three subjects each in the study and controlgroups were matched for age, sex, ethnic group and height. Prevalenceof chronic respiratory symptoms was obtained by questionnaire.Spirometric measurements included forced vital capacity (FVC),forced expiratory volume in the first second (FEV_1.0) and forcedmid-expiratory flow rate (FEF_25–75%). The study grouphad a chest radiograph. The odds ratio for any chronic respiratorysymptom was 11.6 (95% confidence interval [Cl] = 3.7–39.4)in the study group. Mean values for the spirometric tests werelower in the study group; the differences in FEV_1.0 and FEF_25–75%were significant. Tuberculosis was not found in the study group,while one subject (2.4%) had radiological evidence of bronchiectasis.It may therefore be concluded that chronic tea dust exposurecauses increased prevalence of respiratory symptoms and a significantdegree of small airways obstruction.     

Exposure to and acute effects of medium-density fiber board dust

The goals of this study were (1) to investigate workers' exposure to medium-density fiber (MDF) dust (inhalable dust, particle size),formaldehyde, and volatile organic compounds; (2) to study the possible inflammatory nasal reactions caused by exposure to MDF board dust; and (3) to determine the occurrence of irritative symptoms among exposed workers. Nasal lavage fluid was analyzed for cytokines and nitric oxide/nitrite. and inflammatory cells were counted. The time-weighted average of MDF dust was 1.4 mg/m3 in the workers' breathing zones. MDF board dust was composed mainly of particles exceeding 10 microm in diameter. The MDF board dust released formaldehyde in concentration of about 1000 microg/g when extracted with water for 6 hours at 37 degrees C. The cell counts and cytokine levels of the nasal lavage fluid samples did not show statistically significant differences between the workers exposed to MDF board dust and those exposed to other wood dusts. Nevertheless, two MDF-exposed workers had a considerable increase in the proportion of eosinophils and cytokine levels. Several workers exposed to MDF and wood dusts experienced nasal, eye, and skin symptoms at the end of a work shift. Both exposed groups had significantly more nasal symptoms, although the median dust level was only 1.2 mg/m3, considerably less than the occupational exposure limit for wood dust in Finland. Nasal symptoms were more frequent among workers exposed to MDF board dust and did not correlate with smoking. Our results suggest that the occupational exposure limit of 5 mg/m3 is probably too high for MDF board dust.     

SWORD '99: surveillance of work-related and occupational respiratory disease in the UK

Systematic reports from chest and occupational physicians under the SWORD and OPRA (Occupational Physicians Reporting Activity) surveillance schemes continue to provide a picture of the incidence of occupational respiratory disease in the UK. An estimated total of 4393 incident cases (comprising 4530 diagnoses) were reported during the 1999 calendar year, an increase of 1427 cases over the previous year. Benign pleural disease was the single most frequently reported condition (28% of all diagnoses reported). Occupational asthma cases (1168; 26%) remained high, as did mesothelioma (1032; 23%). Analysis of trends over the past 8 years shows an increase in mesothelioma cases, but little change in asthma. The annual incidence per 100,000 employed people, 1996-1999, for mesothelioma, lung cancer and pneumoconiosis was high amongst construction workers (28.7), miners and quarrymen (26.5), woodworkers (18.9) and gas, coal and chemical workers (15.2). Trends in mesothelioma incidence by birth cohort continue to show an increase in construction workers and a continuing decline in shipyard and insulation workers. The relative proportion of pneumoconiosis cases attributed to coal mining has fallen steadily in workers born since approximately 1920 and most cases are now in men who have been employed in quarrying and rock drilling.     

Impairment of nasal mucociliary clearance in woodworkers in the furniture industry

Black, A., Evans, J. C., Hadfield, Esme H., Macbeth, R. G., Morgan, A., and Walsh, M. (1974).British Journal of Industrial Medicine,31, 10-17. Impairment of nasal mucociliary clearance in woodworkers in the furniture industry. Measurements of mucociliary clearance from the anterior end of the middle turbinate were made using technetium-99m-labelled particles in nine woodworkers from the furniture industry and in 12 controls, none of whom had been occupationally exposed to wood dust. Clearance rates in the controls ranged from 1·9 to 18·5 mm min^-1 with a mean of 6·8. These values are in good agreement with measurements reported elsewhere for normal subjects. Only one of the woodworkers had a clearance rate which fell within the normal range and he had been occupationally exposed for the shortest period (6 years). In four woodworkers clearance was very slow (< 1 mm min^-1) and in three there was almost complete stasis. The results of this preliminary investigation suggest that nasal mucociliary function is significantly impaired in workers who have been exposed to wood dust in the furniture industry for more than 10 years.     

Nasal patency and lavage biomarkers in relation to settled dust and cleaning routines in schools.

OBJECTIVES: This study determined the relations between settled dust and cleaning routines in classrooms on one hand, and nasal symptoms, nasal cavity dimensions, and the concentration of selected biomarkers of inflammation in nasal lavage on the other. METHODS: Measurements of settled dust via standardized vacuum cleaning and an investigation of the cleaning routines were performed in 12 randomly selected primary schools in the municipality of Uppsala. Clinical examinations including acoustic rhinometry and nasal lavage were performed in the school environment among 279 school personnel working in the main buildings of the schools. Eosinophil cationic protein (ECP), myeloperoxidase (MPO), lysozyme, and albumin were analyzed in the lavage fluid. The relationships between the medical and hygienic data were analyzed both bivariately and with a multiple regression model controlling for age, gender, smoking, atopy, room temperature, and urban vicinity of the school. RESULTS: The amount of settled dust was positively related to subjective nasal obstruction and smaller nasal cavity dimensions measured with acoustic rhinometry. The noses were less patent, and the levels of ECP or lysozyme in the lavage were increased for the subjects in schools with a lower frequency of floor mopping, a lower frequency of desk cleaning, and where wet mopping was used. CONCLUSIONS: Our results indicate that the actual dust levels in Swedish classrooms can affect the occurrence of nasal obstruction among school personnel. A beneficial effect on the clinical signs of the nasal mucosa was observed for a higher frequency of both floor mopping and desk cleaning, whereas the use of wet mopping seemed disadvantageous in comparison with dry mopping. These findings illustrate the need for adequate cleaning procedures to minimize the environmental effects on the airway mucosa.     

Nasal symptoms and indices of nasal inflammation in flour-dust-exposed bakers

To analyze whether indices of nasal airway inflammation in bakers were related to nasal symptoms and exposure to airborne flour dust. Methods: A cross-sectional study was performed in 12 currently flour-exposed bakers. They were examined by nasal lavage (NAL), visual inspection, a test of mucociliary clearance, and nasal peak expiratory flow (nasal PEF). NAL fluid was analyzed according to the inflammatory markers eosinophil cationic protein (ECP), indicating eosinophilic activity; myeloperoxidase (MPO), indicating active neutrophils; hyaluronic acid (HA) from active fibroblasts; tryptase, indicating activation of mast cells; and albumin, indicating plasma exudation. The bakers were also questioned about respiratory symptoms and working history. Their current and cumulative exposure to inhalable flour dust was estimated after exposure measurements and information about earlier work tasks. Office workers (n = 16) without occupational exposure to dust or any other known nasal irritant or sensitizer served as controls. Results: Personal inhalable dust measurements among the bakers working as dough makers or bread formers ranged from 1.0 to 3.8 mg/m³. Of the 12 bakers, 10 reported at least 1 nasal symptom (crusts, blockage, or a runny nose), a proportion significantly greater than that of the controls (P = 0.009). Bakers with nasal symptoms had higher concentrations of markers of inflammation in their NALs as compared with nonsymptomatic bakers. The difference was significant for MPO (P = 0.02) and HA (P = 0.04) in relation to a runny nose. Tryptase was detected in only one NAL of the bakers. There was a positive correlation between the cumulative dose of inhalable flour dust and concentrations of MPO and HA in NAL. Two bakers were sensitized to wheat; they had the highest NAL concentrations of inflammatory markers. Conclusions: Our results indicate that flour dust exposure in bakers at levels below the current occupational exposure limit causes nasal mucosal inflammation, which, in turn, is related to nasal symptoms. We propose that the inflammation may be nonallergic, characterized by activation of neutrophils and fibroblasts. Received: 16 September 1997 / Accepted: 16 May 1998     

Biomarkers of nasal inflammation in wood-surface coating industry workers

Upper airway symptoms in workers employed in the manufacture of wood products using ultraviolet radiation curing or acid curing of surface coating have been reported. In this study, workers were divided into groups according to exposure: (1) UV-surface coating line, (2) acid curing surface coating line, (3) finishing processes of UV-cured acrylate coated products, (4) finishing processes of of both UV- and acid cured coated wood products, and (5) control group. The workers were examined with nasal lavage in order to investigate inflammatory signs (ECP, tryptase, albumin and microscopy with cell differential counting). UV-line workers and finishers had significantly increased levels of ECP in nasal lavage. There was a positive correlation between exposure time and ECP and albumin levels. Workers with general nasal complaints and atopics had increased levels of ECP. In this study there were findings indicating an inflammatory process in the nasal mucosa in workers exposed to UV radiation curing multifunctional acrylate coatings. The findings indicate an unspecific inflammation and, therefore, a correlation between occupational exposure to acrylate coatings and nasal inflammation seems probable. Am. J. Ind. Med. 33:392–399, 1998. © 1998 Wiley-Liss, Inc.     

Exposure of humans to a volatile organic mixture. III. Inflammatory response.

A set of symptoms has been described during the past two decades that has been called the "sick building syndrome." These symptoms include eye, nose, and throat irritation; headache; mental fatigue; and respiratory distress. It is likely that the volatile organic compounds (VOCs) present in synthetic materials used in homes and office buildings contribute to these symptoms. However, there have been very few studies in which humans have been exposed to known amounts of VOCs under carefully controlled conditions. In this study, 14 subjects were exposed to a mixture of VOCs (25 mg/m3 total hydrocarbon) that is representative of what is found in new homes and office buildings. Because irritations of the nose and throat are symptoms often associated with the upper respiratory tract and may result from an inflammatory response in the upper airways, we used nasal lavage to monitor neutrophil (PMN) influx into the nasal passages following exposure to VOCs. There were statistically significant increases in PMNs, both immediately after a 4-h exposure to VOCs and 18 h later.