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At least 613 records · Page 34Linked to original sources
PubMed2006

Pine dust, atopy and lung function: A cross-sectional study in sawmill workers.

An increased risk of asthma symptoms has previously been shown in 772 pine sawmill workers. The aim of the current study was to assess the association between dust exposure, lung function and atopy. Subjects with (n = 59) and without (n = 167) asthma symptoms were randomly selected from the previous survey. Lung function and atopy were determined using spirometry and skin-prick tests, respectively. Inhalable dust levels were measured on the same day. The geometric mean dust concentration was 0.52 mg x m(-3). Exposure to dry but not to green dust was associated with asthma symptoms. Green dust was associated with atopic sensitisation, particularly against outdoor allergens; no association was found for dry dust. Forced vital capacity, forced expiratory volume in one second and peak expiratory flow were significantly lower in workers exposed to high levels of green dust (-350 mL, -260 mL and -860 mL x s(-1), respectively) and dry dust (-230 mL, -190 mL and -850 mL x s(-1), respectively). These associations were observed both in subjects with and without asthma symptoms. No associations with cross-shift changes in lung function were found. Exposure to green pine sawdust may be a risk factor for atopy. Both green and dry dust were associated with obstructive as well as restrictive pulmonary effects.

Adult↗
PubMedDate not supplied

Job categories and their effect on exposure to fungal alpha-amylase and inhalable dust in the U.K. baking industry.

Enzymes in flour improver, in particular fungal alpha-amylase, are known to be a significant cause of respiratory allergy in the baking industry. This study measured total inhalable dust and fungal alpha-amylase exposures in U.K. bakeries, mills, and a flour improver production and packing facility and determined whether assignment of job description could identify individuals with the highest exposures to fungal alpha-amylase and inhalable dust. A total of 117 personal samples were taken for workers in 19 bakeries, 2 mills, and a flour improver production and packing facility and were analyzed using a monoclonal based immunoassay. Occupational hygiene surveys were undertaken for each site to assign job description and identify individuals who worked directly with flour improvers. Analysis of exposure data identified that mixers and weighers from large bakeries had the highest exposures to both inhalable dust and fungal alpha-amylase among the different categories of bakery workers (p<.01). Currently, the maximum exposure limit for flour dust in the United Kingdom is 10 mg/m(3) (8-hour time-weighted average reference period). In this study 25% of the total dust results for bakers exceeded 10 mg/m(3), and interestingly, 63% of the individuals with exposure levels exceeding 10 mg/m(3) were weighers and mixers. Individuals who worked directly with flour improvers were exposed to higher levels of both inhalable dust and fungal alpha-amylase (p<.01) than those who were not directly handling these products. Before sensitive immunoassays were utilized for the detection of specific inhalable allergens, gravimetric analysis was often used as a surrogate. There was a weak relationship between inhalable dust and fungal alpha-amylase exposures; however, inhalable dust levels could not be used to predict amylase exposures, which highlights the importance of measuring both inhalable dust and fungal alpha-amylase exposures.

Allergens↗
PubMed2000

A pilot study examining changes in dust lead loading on walls and ceilings after lead hazard control interventions.

The U.S. Department of Housing and Urban Development (HUD) guidelines on lead hazard control instruct contractors to clean floors, windows, walls, ceilings, and other horizontal surfaces to remove lead-contaminated dust and debris after lead interventions are conducted. This dust removal activity adds costs to each project. The need to clean floors and windows is well documented in the HUD guidelines. However, there is substantially less documentation to support the recommendation to clean walls and ceilings. We examined whether it is necessary to clean walls and ceilings after lead hazard control (LHC) interventions by comparing dust lead loadings measured on these surfaces before an LHC intervention to dust lead loadings after the intervention. Twenty-two dwelling units undergoing substantial LHC measures consistent with the HUD guidelines were enrolled in the study. There was a significant increase in dust lead loading on walls and ceilings between the pre- and postintervention. The change in wall dust lead loading was substantial and created potentially harmful lead exposures. Although statistically significant, the change in ceiling dust lead loading was minimal and the postintervention dust lead loadings were far below the existing federal floor dust lead clearance standard. These results strongly support the recommendations in the HUD guidelines to clean walls after LHC interventions and do not provide sufficient justification to alter the current recommendation to clean ceilings after lead work.

Child↗
PubMed1986

The chemical composition of standard cotton dust.

Cotton dust samples from Cotton Incorporated were investigated by X-ray fluorescence and proximate analysis methods. These dust samples are known as "standard cotton dust" and have been used by many researchers investigating the causative agent(s) and physiological mechanisms of byssinosis. Silicon, calcium, potassium, and aluminum were present in relatively high concentrations (1-4%) in the dust fractions. The ash content of the dust fractions increased as the fraction particle size decreased. Proximate analyses demonstrate that "noncellulosic organics" are the major class of constituents (35-45%) in cotton dust. Cellulose comprises only 10-15% of the dust, while water-extractable materials comprise approximately 20% of the dust. Capillary gas chromatography performed on silylated, freeze-dried, aqueous extracts of the less than or equal to 38 micron dust fraction revealed the presence of phosphate, malate, arabitol, citrate, fructose, glucose, and mannitol.

Carbohydrates↗
PubMed1998

Chemical speciation of lead dust associated with primary lead smelting.

The research presented in this article assessed geochemical factors relating to dust produced during primary lead smelting. Bulk dust samples and size-selective airborne dust samples were collected from four areas of a primary lead smelter and analyzed by X-ray diffraction and sequential chemical extraction. X-ray diffraction showed that the smelter dusts were composed primarily of sulfides, oxides, sulfates, and silicates of metal ores, with galena being the primary dust component. Sequential extraction revealed the solubility of lead compounds at less than 7% in the exchangeable and mildly acidic steps for the bulk dusts collected from four smelter areas. The later steps of the extraction procedure were more effective in dissolving the lead compounds associated with the bulk dust samples, with 43%, 26%, and 8% of the total lead, in the ore storage, sinter, and blast/dross smelter areas, respectively, being extracted in the residual step. Sequential extraction of coarse airborne dust samples from the ore storage and sinter plant showed that 1.2% and 4.1% of the total lead, respectively, was exchangeable. The finer particle size fractions from these areas of the smelter showed higher percentages of exchangeable lead. Of the course airborne dust from the blast/dross furnace processes, 65% of the total lead was exchangeable. However, the largest percentage of lead from these areas was associated with the finer particle-size fractions. If lead bioavailability is related to its solubility as determined through sequential extraction, the health hazards associated with lead exposure may be appreciably enhanced in the blast and dross furnace processes.

Air Pollutants, Occupational↗
PubMed2002

Airway wall remodeling induced by occupational mineral dusts and air pollutant particles.

OBJECTIVES: COPD has been reported in workers exposed to particulates, and there is increasing evidence that high levels of ambient particulate pollutants may also be associated with COPD. The studies here investigate the hypothesis that particulates, including air pollution particles, can induce airway wall fibrosis, a process that can lead to COPD. DESIGN: Rat tracheal explants were exposed to various occupationally encountered dusts, air pollution particles, and model air pollution particles. In some experiments, iron was loaded onto the particle surface. Gene expression and nuclear factor (NF)-kappaB activation were measured after 7 days of air culture. Adhesion to and uptake of dusts by the tracheal epithelium were also evaluated. RESULTS: Known fibrogenic dusts such as amosite asbestos produced increased gene expression of procollagen, transforming growth factor-beta, and platelet-derived growth factor, and increased hydroxyproline in the explants, and the addition of iron increased these effects. The addition of iron also converted nonfibrogenic TiO2 into a fibrogenic dust. Dusts with surface complexed iron activated NF-kappaB via an oxidant mechanism. However, an ultrafine TiO2 with very low iron was also fibrogenic. In separate experiments, exogenous tumor necrosis factor-alpha increased dust adhesion to, and exogenous ozone increased dust uptake by, tracheal epithelial cells. CONCLUSIONS: Mineral dusts can directly induce fibrosis in the airway wall. Exogenous inflammatory cells and exogenous agents are not required, but they probably exaggerate the fibrogenic effects. An iron-mediated oxidant mechanism underlies the fibrogenic effects of some, but not all, of these dusts. Particle-induced airway wall fibrosis may lead to COPD.

Air Pollutants↗
PubMed2006

Lung disorders of workers exposed to rush smear dust in China.

The aim of this study was to evaluate the lung disorders of the workers exposed to rush smear dust. A cross sectional study was carried out on 1,709 current workers (788 male, 921 female) in 80 factories. All subjects were asked by questionnaire, and health examination including chest X-ray was conducted for 661 workers in 35 factories. Lung function test was also examined for 119 non-smoking males among 661 subjects. Dust samplings were collected and total and respirable dust concentrations at 127 spots in 35 factories were measured. The geometric mean dust concentration in the workshops was up to 20.00 mg/m(3), and the geometric mean respirable dust concentration reached 8.22 mg/m(3). The mean quartz concentration of accumulated dust was 29.2%. The prevalence of radiographic small opacities profusion category > or = 1/0, according to the ILO 1980 Classification System, was 2.6% among 661 employees. One worker was found to have pneumoconiotic findings of 2/2 profusion accompanied with large opacity. The prevalence of pneumoconiosis (1/0 or more) correlated with cumulative dust exposure (r=0.192, p<0.0001). The similar relationship was found between the prevalence rate of cough or sputa and worksite dust concentration. In non-smokers, a positive association was found between the prevalence of cough and occupational exposure duration (r=0.080, p=0.004). Approximately 19.3% and 34.5% of employees suffered from respiratory impairment for FVC and FEV1.0, respectively. This is the first report of "rush" pneumoconiosis in China. Rush mat workers were found to be at high risk for pneumoconiosis, a preventable disease. Our results showed a dose-response relationship between rush-mat dust level and the prevalence of pneumoconiosis. Similar relationship between the prevalence of cough and sputum and the work duration was found for non-smoking workers but not for smoking workers.

Adult↗
PubMedDate not supplied

House dust mite allergy in Florida. Mite survey in households of mite-sensitive individuals in Tampa, Florida.

This study evaluated the prevalence of positive house dust mite skin tests in a population of atopic individuals and identified the mite species present in mattress and house dust samples in homes of the Tampa Bay area. Four hundred consecutive individuals were evaluated for respiratory complaints and skin tested with standardized extracts of Dermatophagoides pteronyssinus (Dp) and Dermatophagoides farinae (Df). Two hundred forty individuals (60%) had a positive skin test to the mite extracts. Dust samples were collected in 40 homes of mite-allergic individuals and analyzed by light microscopy. Mite species were found in 53 of the 60 dust samples (20 mattresses and 40 carpets). Mite numbers ranged from 110-6200 mites/g of mattress dust and from 120-5500 mites/g of carpet dust. Eleven different mite species were identified and Blomia tropicalis (Bt), not previously identified in the United States, was found in 30% of the samples. Dp and Df wee the predominant species. These observations suggest that house dust mite allergy is common in the Tampa Bay area and that the house dust mite fauna comprises several mite species besides Dp and Df. Prospective studies in progress are designed to confirm the role of different mite species in house dust mite allergy.

Air Pollutants↗
PubMed2005

Effect of composition and different fractions of hay dust suspension on inflammation in lungs of heaves-affected horses: MMP-9 and MMP-2 as indicators of tissue destruction.

REASONS FOR PERFORMING STUDY: Airway matrix metalloproteinases (MMPs) increase following inhalation of organic dust. The relative contribution of dust components to this elevation is unknown. OBJECTIVE: To identify components of organic dust responsible for elevated MMP levels in equine airways. METHODS: Bronchoalveolar lavage (BALF) from 7 heaves-susceptible horses, collected 6 h following inhalation challenges with saline, 2 different hay dust suspensions (HDS-1 and -2) and soluble and particulate fractions of HDS-1, were analysed for MMP-2 and -9 using SDS-page gelatin zymography. RESULTS: HDS-1 challenge increased BALF proMMP-9 and total MMP-9. HDS-1 fractions, or the particulate fraction with added lipopolysaccharide, increased BALF proMMP-9 and total MMP-9 in combination, but not when inhaled separately. HDS-2 inhalation elevated BALF complex forms, proMMP-9, active MMP-9, total MMP-9 and total MMP-2. CONCLUSIONS: The results suggest synergistic action of soluble and particulate organic dust components. The fact that HDS-1 and HDS-2 had different glucan concentrations supports a role for moulds in the activation of MMP-9. POTENTIAL RELEVANCE: Activation and release of MMPs in response to inhaled moulds are involved in the aetiopathogenesis of heaves. Endotoxin contributes to the synergistic action of the dust components, but the overall MMP response to organic dust inhalation in heaves-susceptible horses largely reflects the mould content of the dust. In the future, inhibition of MMP production and release may offer therapeutic means for treatment and prevention of heaves and recommendations for acceptable dust levels can be given.

Animals↗
PubMed1994

Changes in ventilatory function in grain processing and animal feed workers in relation to exposure to organic dust.

OBJECTIVES: The effects of organic dust exposure on the configuration of the maximum expiratory flow volume (MEFV) curve was examined multivariately. METHODS: Data from 390 male workers in the animal feed industry in The Netherlands were analyzed. A multivariate technique called nonlinear canonical correlation analyses was used to study the relationship between a set of organic dust exposure variables and a set of ventilatory function variables. RESULTS: The results indicate an almost independent effect of the overall mean organic dust exposure and the number of years of organic dust exposure on ventilatory function. Increasing mean organic dust exposure was associated with a decrease in both forced expiratory volume in 1 s (FEV1.0) and forced vital capacity (FVC) and decreased flows at high lung volumes only. Increasing number of years of dust exposure was associated with a decrease in FEV1.0 and a decrease in flow at all lung volumes, while the FVC seemed relatively constant. These two distinct patterns of reduction in ventilatory function may represent two different pathological processes. Whereas workers with prolonged exposure showed reduced values for all of the MEFV curve variables, except the FVC, those with only a few years of exposure especially showed a decrease in FVC and peak expiratory flow. The effect of current organic dust exposure was more evident for nonsmokers than for ex-smokers and current smokers. CONCLUSION: The major finding of this study was an independent effect of overall mean organic dust exposure and the number of years of organic dust exposure on the MEFV curve.

Adult↗
PubMed1999

Personal exposure to dust, endotoxin and crystalline silica in California agriculture.

AIMS: The aim of this study was to measure personal exposure to dust, endotoxin and crystalline silica during various agricultural operations in California over a period of one year. METHODS: Ten farms were randomly selected in Yolo and Solano counties and workers were invited to wear personal sampling equipment to measure inhalable and respirable dust levels during various operations. The samples were analysed for endotoxin using the Limulus Amebocyte Lysate assay and crystalline silica content using X-ray diffraction. In total 142 inhalable samples and 144 respirable samples were collected. RESULTS: The measurements showed considerable difference in exposure levels between various operations, in particular for the inhalable fraction of the dust and the endotoxin. Machine harvesting of tree crops (Geometric mean (GM) = 45.1 mg/m3) and vegetables (GM = 7.9 mg/m3), and cleaning of poultry houses (GM = 6.7 mg/m3) showed the highest inhalable dust levels. Cleaning of poultry houses also showed the highest inhalable endotoxin levels (GM = 1861 EU/m3). Respirable dust levels were generally low, except for machine harvesting of tree crops (GM = 2.8 mg/m3) and vegetables (GM = 0.9 mg/m3). Respirable endotoxin levels were also low. For the inhalable dust fraction, levels were reduced considerably when an enclosed cabin was present. The percentage of crystalline silica was overall higher in the respirable dust samples than the inhalable dust samples. CONCLUSIONS: Considerable differences exist in personal exposure levels to dust, endotoxin and crystalline silica during various agricultural operations in California agriculture with some operations showing very high levels.

Agriculture↗
PubMed1998

[Comparative study on the retention effect of the inhaled mineral and coal dusts in rat lung].

The pulmonary retention and physico-chemical characteristics of the dust are very important factors in the occurrence of pneumoconiosis. This paper reports a comparative study on the retention characteristics between the inhaled mineral dust and coal dust in rat lung. The dust quantities in the lungs and the mediastinal lymphatic nodes were determined by the formic acid digestion method. The results showed that the pulmonary retention quantities of the coal dust in rats were higher than those of the mineral dust on the third day but lower on the 90th day after exposure for two weeks. The results suggest that the mineral dust can deposit in the lung longer than the coal dust, and the lymphatic system is important for the pulmonary elimination of the dust.

Animals↗
PubMed2002

[Evaluation of occupational exposure to dusts of mixed free crystalline silica and natural respirable mineral fibers].

An appropriate evaluation of exposure to dust containing both crystalline silica and asbestos (e.g., some mines of rock materials, installation and disassembly of thermal insulation and frictional products etc.) requires that the presence of these two potentially carcinogenic dust components should be taken into account. In Poland, the present legal regulations provide for rather extensive freedom in both defining the scope of studies performed and interpreting their results. In consequences, the evaluation of dust exposure at similar workposts in different plant is based on different criteria, which means that in some cases the presence of free crystalline silica (MAC value for dust containing from 2 to 50% of SiO2--is 4 mg/m3 for total dust and 1 mg/m3 for respirable dust) is taken into account, and in others the presence of mineral fibers such as chrysotile and other fibrous mineral except for crocidolite (MAC value--1 mg/m3 and 0.2 f/cm3, respectively). The evaluation of exposure usually involves only one factor, i.e. free silica crystalline (more favorable for the administration of a given plant). The present study reveals that depending on the criterion adopted for evaluating the exposure at a given workpost (e.g. exchange of thermal insulation), the working conditions may be classified as safe (criterion for the presence of SiO2) or as harmful to workers' health if a complete composition of mineral dust (chrysotile, amosite, quartz) is considered. In order to clarify the present situation, the authors present in this paper the proposals on the scope of required studies (measurements of total and respirable dust, as well as respirable mineral fibers concentrations, determination of SiO2 contents, identification of dust crystalline phases) and the principles on which the interpretation of results should be based.

Air Pollutants, Occupational↗
PubMed2000

[Relationship between the ultrastructural characteristic of coal dust and its toxicity].

To study the relationship between the ultrastructural characteristic of coal dust and its toxicity, we compared two types of coal dusts which damaged alveolar macrophages(AMs) concerning with the coal dusts ultrastructural characteristic by using microscopy and biochemical techniques. The results showed that coal dusts damaged not only AMs plasma and lysosomal enzymes but also in ultrastructure. The coal dust in Nanpiao mine had a sharp form, fragile texture and a structure putting in order. It was concluded that: (1) the toxicity of coal dust in Nanpiao mine was higher than in Kailuan mine and which was related to the ultrastructural feature of the coal dusts; (2) the AMs injury degree by coal dusts was more and more serious with the duration of exposure to coal dusts.

Animals↗
PubMed2002

[Study on the method for demonstrating dust granules in phagocytes with Warthin-Starry special staining].

OBJECTIVE: To search a method for showing dust granules in phagocytes. METHODS: The autopsy samples of 10 cases who died of non-pulmonary diseases(group A), 6 cases with silicosis(group B) and 5 cases of dead fetus(group C) were collected. The samples of lung, spleen and lymphnodes were stained by methods of (1)HE staining; (2)Warthin-Starry staining(W-S staining) and modified W-S staining; (3) CD68 (as a first antibody) immunohistochemical staining. The ultrastructure and chemical component of the dust granules in the pulmonary phagocytes(dust cells) of group A(3 cases) and group B(3 cases) were observed and analyzed by transmission electron microscope(TEM) and analytic electron microscope(AEM). RESULTS: In group A and B smaller or minute dust granules which could not be shown by HE staining method were clearly shown by W-S staining and modified W-S staining methods. There were no positive granules found in group C. The CD68 marker of the dust cells was positive. The size, shape, density and chemical elements of the dust granules of group A were different from those of group B under TEM and AEM, excluding bacteria and other intracellular contents. CONCLUSION: The dust granules in the phagocytes could be shown by W-S staining method, its staining effect for minute dust granules is superior to general HE staining. However, the determination of chemical elements of dusts must depend on AEM.

Antigens, CD↗
PubMed2003

[Study on the pulmonary fibrogenetic effect induced by rush-mat dust in rats].

OBJECTIVE: To investigate the fibrogenetic effects induced by rush-mat dust in rats. METHODS: SD rats were treated with 50 mg of rush-mat dust per rat by intra-tracheal instillation, sacrificed 3, 6, and 12 months respectively after exposure. The lung tissue and lung lymph-node were taken out for pathological and electron microscopic examination. The content of collagen and ceruloplasmin (CP) in lung tissues were also determined. RESULTS: After treatment for 12 months, fresh wet lung weight in rush-mat dust group [(2.69 +/- 0.22) g] was higher than those in saline group [(1.87 +/- 0.25) g], TiO(2) group [(2.25 +/- 0.26) g], but lower than that in SiO(2) group [(11.41 +/- 1.63) g]; dry lung weight in rush-mat dust group [(0.47 +/- 0.03) g] was higher than those in saline group [(0.32 +/- 0.03) g], TiO(2) group [(0.41 +/- 0.08) g], but lower than that in SiO(2) group [(2.06 +/- 0.28) g]; lung collagen content in rush-mat dust group [(103.08 +/- 14.79) mg] was higher than those in saline group [(75.96 +/- 13.91) mg, TiO(2) group [(85.84 +/- 17.62) mg], but lower than that in SiO(2) group [(497.50 +/- 100.80) mg]; CP content in rush-mat dust group [(18.03 +/- 1.87) U/L] was higher than those in saline group [(15.05 +/- 2.24) U/L], TiO(2) group [(16.92 +/- 1.67) U/L], but lower than that in SiO(2) group [(25.37 +/- 3.58) U/L], P < 0.05 or P < 0.01. Pathological examination showed lung macrophage alveolitis, broadening of alveolar interval, one to two grade of silicotic nodes and increased amount of type II epithelial cell in alveolar as well as slight collagenous fibrosis in lung tissue of rush-mat dust group. Under electron microscope, primary and secondary lysosome and medullary sheath-like phagocytic residual body were found in lung tissue of rush-mat dust group, meanwhile the amount of type II alveolar epithelial cell and collagen fiber were slightly increased but these changes were less than those of quartz group. CONCLUSION: The rush-mat dusts have slight pulmonary fibrogenetic effect on rat.

Animals↗
PubMed2004

Evaluation of dust activity and climate effects in North China.

TOMS/AI data with nearly 20 years are utilized in the paper to evaluate dust activities in North China. Combined with simultaneous NCEP reanalysis climate data, climate effects on dust activities are assessed. The results showed that the whole North China suffers impact by dust aerosols, with three centers standing out in TOMS/AI spring average map that are western three basins, which are characterized by lower annual precipitation and elevation. Gobi deserts in Mongolia Plateau do not attain higher TOMS/AI value due to cloud contamination and relative higher elevation. Spring is the season with the highest TOMS dust aerosol index; within the western three basins, high dust aerosol index appears in both spring and summer, especially in Tarim Basin. Wind speed in spring and precipitation in previous rainy season play important roles in controlling dust activities, higher wind speed and less precipitation than the normal are in favor of dust activities in spring. Temperature in spring and previous winter also affect dust activity to a certain extent, but with contrary spatial distribution. Temperature in winter exert effect principally in west part, contrarily, temperature effect in spring is mainly shown in east part. Both of them have negative correlation with dust activity.

China↗
PubMed2006

[Numerical simulations of spatial and temporal characteristics of airborne dust over Asia during springs of 2000 to 2002].

Spatial and temporal characteristics of airborne dust over Asia during springs of 2000, 2001 and 2002 were simulated with a mineral dust entrainment and deposition model (DEAD) embedded in a global model of atmospheric transport and chemistry (MATCH) using the real-time meteorological data as forcing fields. The results show a good agreement of the pattern of model-simulated atmospheric dust concentration with the distribution of surface-observed spring dust storm frequency and a significant correlation between the simulated dust aerosol optical depth (DAOD) and satellite-observed aerosol index (AI). These results validate applicability of the integrated model in simulating dust entrainment, transportation and deposition and describing spatial and temporal characteristics of dust loading over the Asian continent. In addition, an attempt was made to explore possible paths of dust transportation by use of correlation analyses between the simulated dust emission flux (DEF) and DAOD.

Air Movements↗