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PubMed2005

A survey of spatially distributed exterior dust lead loadings in New York City.

This work documents ambient lead dust deposition values (lead loading) for the boroughs of New York City in 2003-2004. Currently, no regulatory standards exist for exterior concentrations of lead in settled dust. This is in contrast to the clearance and risk assessment standards that exist for interior residential dust. The reported potential for neurobehavioral toxicity and adverse cognitive development in children due to lead exposure prompts public health concerns about undocumented lead sources. Such sources may include settled dust of outdoor origin. Dust sampling throughout the five boroughs of NYC was done from the top horizontal portion of pedestrian traffic control signals (PTCS) at selected street intersections along main thoroughfares. The data (n=214 samples) show that lead in dust varies within each borough with Brooklyn having the highest median concentration (730 microg/ft2), followed in descending order by Staten Island (452 microg/ft2), the Bronx (382 microg/ft2), Queens (198 microg/ft2) and finally, Manhattan (175 microg/ft2). When compared to the HUD/EPA indoor lead in dust standard of 40 microg/ft2, our data show that this value is exceeded in 86% of the samples taken. An effort was made to determine the source of the lead in the dust atop of the PTCS. The lead in the dust and the yellow signage paint (which contains lead) were compared using isotopic ratio analysis. Results showed that the lead-based paint chip samples from intact signage did not isotopically match the dust wipe samples taken from the same surface. We know that exterior dust containing lead contributes to interior dust lead loading. Therefore, settled leaded dust in the outdoor environment poses a risk for lead exposure to children living in urban areas, namely, areas with elevated childhood blood lead levels and background lead dust levels from a variety of unidentified sources.

Air Pollutants↗
PubMed2005

Characterization of oak and birch dust-induced expression of cytokines and chemokines in mouse macrophage RAW 264.7 cells.

Occupational exposure to wood dust is related to several respiratory diseases, such as allergic rhinitis, chronic bronchitis, and asthma. However, virtually nothing is known about molecular mechanisms behind wood dust-induced pulmonary inflammation. To elucidate the effects of wood dust exposure on cytokine and chemokine expression in murine macrophage cell line cells, mouse RAW 264.7 cells were exposed to two selected hardwood dusts, oak and birch. TiO2 and LPS were used as controls. Expression patterns of several cytokines, chemokines, and chemokine receptors were assessed by real-time quantitative PCR system and by ELISA. Exposure to birch dust caused a major increase in TNF-alpha and IL-6 protein levels whereas a weaker induction of TNF-alpha protein was found after exposure to oak dust. Inorganic TiO2 dust did not induce significant cytokine expression. With respect to the chemokines, a dose-dependent, about 10-fold induction of CCL2 mRNA and protein was found after exposure to birch dust. Oak dust induced weakly CCL2 protein. Similarly, birch dust induced a strong expression of CCL3, CCL4, and CXCL2/3 mRNA whereas only moderate levels of these chemokine mRNAs were detected after oak dust exposure. In contrast, expression of CCL24 mRNA was inhibited by more than 40-fold by both oak and birch dusts. TiO2 dust induced about five-fold expression of CCL3 and CCL4 mRNA but did not affect significantly other chemokines. These results suggest that exposure to birch or oak dusts may influence the development of the inflammatory process in the airways by modulating the expression of macrophage-derived cytokines and chemokines.

Animals↗
PubMed2005

Field performance of the RespiCon for size-selective sampling of industrial wood processing dust.

The RespiCon sampler is a multistage virtual impactor that simultaneously collects the ISO/CEN/ACGIH size fractions of inhalable, thoracic, and respirable particulate matter. The field performance of the device for measurement of industrial wood processing dust was evaluated against reference size-selective samplers: the IOM sampler (inhalable dust), the GK 2.69 cyclone (thoracic dust), and the SKC aluminum cyclone (respirable dust). Seventy-one sets of area samples were collected from 10 wood processing plants, with the samplers mounted either in the free-field or on a two-dimensional bluff body. The geometric mean (range) dust levels across all plants measured by the reference samplers were: inhalable, 1.35 mg/ m3 (0.11-11.06); thoracic, 0.31 mg/m3 (0.05-1.38); and respirable, 0.10 mg/m3 (0.02-0.54). In comparing the RespiCon with the reference samplers, there was no significant difference between sampling in the free-field versus bluff-body modes. For inhalable dust, there was no significant difference between the RespiCon and the IOM sampler after applying a correction factor of 1.5 to the extrathoracic data obtained from the RespiCon. Without the correction factor, the RespiCon undersample inhalable dust by an average of 23%. For thoracic dust, the RespiCon was shown to oversample the extrathoracic dust fraction resulting in an overall error of 48%. A simple correction based on the inhalable and thoracic dust levels reported by the RespiCon is proposed. For respirable dust, there was a significant difference between the RespiCon and the SKC cyclone, but the data were equivocal due to imprecision in measurement of the low respirable dust concentrations encountered and the likelihood of bias in the reference sampler. Overall, the RespiCon sampler appears to be a suitable size-selective sampling device for industrial wood processing dust, although adjustments should be made to the inhalable and thoracic dust results.

Dust↗
PubMed1994

Fungal propagules in house dust. II. Relation with residential characteristics and respiratory symptoms.

As part of a case-control study on the relation between home dampness and respiratory symptoms of children, house-dust samples were collected from bedroom floors and mattresses in 60 homes in The Netherlands. The house-dust samples were analyzed for the presence of fungal propagules by plating 30 mg of dust directly onto DG18 agar. A checklist and questionnaire were used to obtain information on the home characteristics and occupant behavior that may have an effect on the presence of fungal propagules in house dust. The geometric mean (GM) numbers of colony-forming units (CFU)/g dust collected from the floors was 8990. The number of CFU/g dust was significantly higher in dust from carpeted floors than in dust from smooth floors (GM, respectively, 12,880 CFU/g dust and 3530 CFU/g dust). The GM number of CFU/g dust collected from mattresses was 6760. Overall, the mean numbers of CFU/g dust collected from floors and mattresses were higher in bedrooms where damp spots mold growth, or both were observed. However, these differences were not statistically significant. The relation between home characteristics and the number of CFU/g dust of the most frequently isolated mold species (n = 17), including Alternaria alternata, Cladosporium cladosporioides, Penicillium brevicompactum, and Scopulariopsis brevicaulis, was also investigated. Only the type of flooring had a significant and consistent effect on the number of CFU/g floor dust of the different mold species.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed2004

Sensitization to house dust mites in Reykjavik, Iceland, in the absence of domestic exposure to mites.

BACKGROUND: House dust mites are common sources of indoor allergens. In Reykjavik, Iceland, 9% of the young adult population had serum-specific IgE to Dermatophagoides pteronyssinus. Sensitization to mites is usually assumed to be due to exposure to house dust mites in the indoor environment. This investigation was carried out to measure the concentrations of house dust mite allergens and to investigate which species of mites were present in beds in Iceland. METHODS: A total of 197 randomly selected adults were visited at home using the European Community Respiratory Health Survey (ECRHS) II Indoor protocol. Dust samples were collected from mattresses for measurement of house dust mite allergen concentrations and to estimate the number and type of house dust mites. Additional samples from mattresses and floors were collected from the homes of 10 patients with positive skin prick tests (SPT) to D. pteronyssinus. House dust mite allergen concentrations were measured using ELISA and examination of mite species was carried out using microscopy. Climatic parameters were assessed using psychrometer readings in the bedrooms and outdoors. RESULTS: We found two single mite specimens, both D. pteronyssinus, in two dust samples. Mite allergen analyses indicated that two other dust samples had Der f 1 results close to the cut-off of 0.1 microg/g of dust. No samples were positive for Der p 1. In an additional collection of dust from the homes of 10 SPT-positive patients no Dermatophagoides spp. were found. CONCLUSIONS: Reykjavik citizens are exposed to extremely low amounts of house dust mite allergens in their homes. Possible alternative sources for sensitization are discussed, such as bird nests, exposure from travelling abroad, or other mites or invertebrates that cross-react with house dust mite allergens. Our findings suggest that exposures other than to house dust mites indoors are possible sources of mite allergen exposure.

Adult↗
PubMed2006

Occupational exposure to eight organic dusts and respiratory cancer among Finns.

BACKGROUND: There is inconclusive evidence concerning cancer risks of organic dusts. AIM: The carcinogenic exposures are mainly inhalatory and the authors therefore studied associations between occupational exposure to eight different organic dusts and respiratory cancers in Finland. METHODS: The authors followed up a cohort of all economically active Finns born between 1906 and 1945 for 30 million person-years during 1971-95. Incident cases of nasal, laryngeal, and lung cancer and mesotheliomas were identified through a record linkage with the Finnish Cancer Registry. Occupations from the population census in 1970 were converted to exposures to eight organic dusts with a job-exposure matrix (FINJEM). Cumulative exposure (CE) was calculated as a product of prevalence, level, and estimated duration of exposure. Standardised incidence ratios (SIR) and 95% confidence intervals (CI) adjusted for age, period, and social class were calculated for each organic dust using the economically active population as the reference. RESULTS: A total of 20 426 incident cases of respiratory cancer were observed. Slightly increased risk was observed among men exposed to wood dust for nasal cancer (SIR 1.42, 95% CI 0.79 to 2.44). For laryngeal cancer, men exposed to plant dust (mainly grain millers) had a raised SIR in the high exposure class (SIR 3.55, 95% CI 1.30 to 7.72). Men exposed to wood dust had a raised SIR for lung cancer, but only in the low exposure class (SIR 1.11, 95% CI 1.04 to 1.18). Women exposed to wood dust showed an increased SIR for mesotheliomas in the low exposure class (SIR 4.57, 95% CI 1.25 to 11.7) and some excess in the medium exposure category. CONCLUSIONS: Exposure to organic dusts is unlikely to be a major risk factor of respiratory cancer. Even exposure to wood dust which is a major exposure in Finland seems to have minor effect for nasal cancer. The authors found suggestive evidence that exposure to grain dust may increase the risk of laryngeal cancer, and some support to the hypothesis that exposure to textile dust, and to plant and animal dust (agricultural dusts) may decrease the risk of lung cancer.

Adult↗
PubMed1990

Inflammation in the lungs of rats after deposition of dust collected from the air of wool mills: the role of epithelial injury and complement activation.

In a previous study assessing respiratory symptoms in individuals employed in wool textile mills in the north of England relations between symptoms of chronic bronchitis, breathlessness and wheeze, and rhinitis and current exposure to airborne mass concentration of dust were shown. As preliminary steps in defining the potential hazard associated with dust from the air of wool mills the ability of inspirable dust, collected from the air of wool textile mills, to cause inflammation when injected into the lungs of rats was determined. Dusts were collected from the beginning of wool processing (opening) in one factory and from the middle (combing) and late (backwinding) stages of the process in two other factories. Ability of the dusts to cause inflammation was assessed by instillation into the lungs of rats followed by bronchoalveolar lavage. All the dusts caused some inflammation which peaked on day 1 and did not persist beyond one week. A distinctive aggregation response of mononuclear cells in the lavage, however, had a different time course, peaking at day 7. An attempt was made to determine how the wool mill dusts caused inflammation and experiments showed that the dusts themselves had no inherent chemotactic activity but that they did have a pronounced ability to generate chemotaxins in serum and so could activate complement in lung fluid. In addition, dust collected from ledges in the mills had the ability to injure epithelial cells in vitro which could also contribute to inflammation. A role for endotoxin in the inflammatory activity of the dusts was not discounted and a leachate of the dust had the ability to cause inflammation when injected into the lungs of rats. Wool mill dust is likely to be a complex mixture of materials and these experiments represent a preliminary approach to understanding the biological activity of the whole unfractionated dust and further studies are in progress to define more accurately the toxic material(s) in the dust.

Animals↗
PubMed1998

Risk of pulmonary tuberculosis relative to silicosis and exposure to silica dust in South African gold miners.

OBJECTIVES: To investigate the following questions. (1) Is silica dust on its own, without the presence of silicosis, associated with an increased risk of pulmonary tuberculosis (PTB) in workers exposed to silica dust? (2) In the absence of silicosis is the excess risk dose related? (3) What is the predominant chronological sequence between the development of PTB and the development of silicosis after the end of exposure to dust? METHODS: A cohort of 2255 white South African gold miners has been followed up from 1968 to 1971, when they were 45-55 years of age, to 31 December 1995 for the incidence of PTB. During the follow up 1592 (71%) men died. Of these, 1296 (81%) had a necropsy done at the National Centre for Occupational Health (NCOH) to determine the presence of silicosis and PTB. The incidence of PTB in the cohort was studied relative to cumulative exposure to dust and the onset of silicosis. For the miners with necropsy, the incidence for PTB was studied relative to the severity of silicosis found at necropsy. RESULTS: There were 115 subjects who developed PTB. The total person-years of follow up was 39,319. For the whole cohort, the factors associated with increased risk of PTB were cumulative exposure to dust (mg/m3.y) (the adjusted rate ratio (RR) 1.07; (95% confidence interval (95% CI) 1.04 to 1.10)), silicosis diagnosed radiologically (3.96 (2.59 to 6.06)), and tobacco pack-years (1.02 (1.01 to 1.03)). The RR (95% CI) for PTB increased with increasing quartiles of cumulative exposure to dust 1.0, 1.51 (0.78 to 2.91), 2.35 (1.28 to 4.32), and 3.22 (1.75 to 5.90). In miners who did not have radiologically diagnosed silicosis (n = 1934, PTB = 74), the adjusted RR (95% CI) for PTB and cumulative exposure to dust was 1.10 (1.06 to 1.13), and increased with quartiles of cumulative exposure to dust as 1.00, 1.46 (0.70 to 3.03), 2.67 (1.37 to 5.23), and 4.01 (2.04 to 7.88). For the subjects who had a necropsy (n = 1296, PTB = 70), the adjusted RR (95% CI) for PTB increased with the severity of silicosis found at necropsy; 1.0 for no silicosis, 1.88 (0.97 to 3.64) for negligible, 2.69 (1.35 to 5.37) for slight, and 2.30 (1.16 to 4.58) for moderate or marked silicosis. For subjects who had a necropsy and no silicosis (n = 577, PTB = 18), the adjusted RR (95% CI) increased slightly with quartiles of cumulative dust 1.0, 1.11 (0.31 to 4.00), 1.42 (0.43 to 4.72), and 1.38 (0.33 to 5.62). CONCLUSION: Exposure to silica dust is a risk factor for the development of PTB in the absence of silicosis, even after exposure to silica dust ends. The risk of PTB increases with the presence of silicosis, and in miners without radiological silicosis, with quartiles of exposure to dust. The severity of silicosis diagnosed at necropsy was associated with increasing risk of PTB and even < 5 nodules--that is, undetectable radiologically--was associated with an increased risk of PTB. The diagnosis of PTB was on average 7.6 years after the end of exposure to dust, at around 60 years of age. The onset of radiological silicosis preceded the diagnosis of PTB in 90.2% of the cases with PTB who had silicosis. The results have implications for medical surveillance of workers exposed to silica dust after the end of exposure.

Adult↗
PubMed2000

Exposures and health effects from inorganic agricultural dusts.

Most studies of respiratory disease from dust exposure in the agricultural workplace have focused on allergic diseases caused by inorganic dusts, specifically occupational asthma and hypersensitivity pneumonitis. Exposures to inorganic (mineral) dusts among farmers and farm workers may be substantial. Such exposures are most frequent in dry-climate farming regions. In such locations farming activities that perturb the soil (e.g., plowing, tilling) commonly result in exposures to farm operators of 1-5 mg/m(3) respirable dust and >= 20 mg/m(3) total dust. The composition of inorganic dust in agriculture generally reflects the soil composition. Crystalline silica may represent up to 20% of particles, and silicates represent up to 80%. These very high concentrations of inorganic dust are likely to explain some of the increase in chronic bronchitis reported in many studies of farmers. Pulmonary fibrosis (mixed dust pneumoconiosis) has been reported in agricultural workers, and dust samples from the lungs in these cases reflect the composition of agricultural soils, strongly suggesting an etiologic role for inorganic agricultural dusts. However, the prevalence and clinical severity of these cases are unknown, and many exposures are to mixed organic and inorganic dusts. Epidemiologic studies of farmers in diverse geographic settings also have observed an increase in chronic obstructive pulmonary disease morbidity and mortality. It is plausible that agricultural exposure to inorganic dusts is causally associated with chronic bronchitis, interstitial fibrosis, and chronic obstructive pulmonary disease, but the independent contribution of mineral dusts beyond the effects of organic dusts remains to be determined.

Agriculture↗
PubMed2002

[An investigation on dust exposure level in workers of geological prospecting occupation].

OBJECTIVE: To make sure of the harmfulness degree of the dust in geological prospecting occupation. METHODS: The determination of respirable dust, total dust and the free silica concentrations was carried out at different working spots exposed to dust. Personal sampling equipment was used to collect the respirable dust. The data of respirable dust concentration in the research was compared to the historical data. RESULTS: As for respirable dust concentration level, 47.95% of 765 silica dust spots of geological prospecting occupation in 9 provinces(autonomous regions) were beyond the criteria. The profession and work type of the highest dust concentration was chiseling and sampling of geological prospecting [from 1996-2000, the dust concentration was (6.15 +/- 3.12) mg/m3]. The ratio of respirable dust to total dust was high in geological prospecting workers. The FSiO2 contentin dust to which geological prospecting workers exposed was high too. CONCLUSIONS: The respirable dust concentration of some types of work in geological prospecting occupation was obviously higher than the national criteria, especially in chiseling, sampling and drilling workers.

Dust↗
PubMed2005

[Dust storms trend in the Capital Circle of China over the past 50 years and its correlation with temperature, precipitation and wind].

The trends of number of dust storm days of the selected 11 meteorological stations from their established year to 2000 as well as their correlations with temperature, precipitation and wind are revealed. The number of dust storm days of the Capital Circle of China is distinctly variable in space and time. The numbers of dust storm days of the western area are far more than those of the eastern area. The interannual variability of number of dust storm days is remarkable. The number of dust storm days of the following 7 stations, Erlianhaote, Abaga, Xilinhaote, Fengning, Zhangjiakou, Huailai and Beijing, declined along the past decades, but those of the other four stations had no significant upward or downward trends. There is a marked seasonality of the number of dust storm days, and the maximum was in April. The correlation between number of dust storm days and number of days of mean wind velocity > 5 m/s, which is critical wind velocity to entrain sand into the air, was strongest among the three climatic factor. There were significant positive correlations between the number of dust storm days and number of days of mean wind velocity > 5 m/s in 6 stations. The second strongest climatic factor correlated with the number of dust storm days is temperature. There are significant negative correlations between the number of dust storm days and mean annual temperature, mean winter temperature, mean spring temperature in 3 or 4 stations. The correlation between the number of dust storm days and precipitation is weakest. Only one station, Zhurihe, showes significant negative correlation between the number of dust storm days and spring rainfall. There are 4 stations whose number of dust storm days don't significantly correlate with the climate. In the end, the spatial-temporal variability of dust storms and its relation with climate in the Capital Circle of China were discussed thoroughly.

Air Pollutants↗
PubMed1979

An investigation into the cytotoxicity of respirable dusts from British collieries.

A series of respirable dusts from British collieries was collected and analysed for mineral content and physical characteristics. Where possible 2 samples of dust were collected from the same site at 8-month intervals. All dusts were tested for their cytotoxic potential using a permanent line of macrophage-like cells (P388D1). In addition, for some dusts, a haemolytic technique was used. With both techniques a positive overall correlation was found between cytotoxicity and the total ash content of the dusts. When the results from collieries producing high- and low-rank coals were considered separately, however, it was found that the ash content of high-rank dusts (r=0.75) showed a much closer correlation with cytotoxicity than low-rank dusts (r=0.40). With the cell test system the ash components, kaolin and mica (r=0.58) and to a lesser extent quartz (r=0.48) showed significant positive correlations with cytotoxicity for high-rank coal dusts but not for low. Using the haemolytic system, however, only the quartz content of the high-rank dusts showed a significant relationship (r=0.69) to levels of haemoglobin release. Both the results of mineralogical analysis of dust samples and cytotoxicity tests showed that the mineral content and cytotoxic potential of dusts collected from the same colliery, and even from the same underground site, at different times, varied considerably. A poor correlation was found between cytotoxicity and various measurements of pneumoconiosis risk but this may well be partly due to this great variation of dust composition with time. In general, the overall results of this study were in good agreement with those of previous work on coal dust toxicity in that both the rank and composition of colliery dusts were found to be of importance, whereas the role of quartz remained enigmatic.

Cell Line↗
PubMed2001

House dust mite avoidance measures for perennial allergic rhinitis.

BACKGROUND: In developed countries, it is estimated that 15% of the general population suffer from one or more allergic disorders, of which allergic rhinitis is the most common. Perennial rhinitis is most often due to allergy to the house dust mite. In such patients, house dust mite avoidance is logical, but there is considerable uncertainty regarding the efficacy and effectiveness of interventions designed to reduce dust mite exposure. OBJECTIVES: To assess the benefit (and harm) of measures designed to reduce house dust mite exposure in the management of house dust mite sensitive allergic rhinitis. SEARCH STRATEGY: We searched the Cochrane Controlled Trials Register, Central, MEDLINE and EMBASE. No restrictions on the language of publication were employed. The bibliography of each paper and other published reviews were checked for further references. We wrote to first authors of all included trials in an attempt to identify further published and unpublished trials. SELECTION CRITERIA: Randomised controlled trial (with or without blinding), in which house dust mite control measures have been evaluated in comparison with placebo or other dust mite avoidance measures, in patients with clinician diagnosed allergic rhinitis and confirmed allergy to dust mite. DATA COLLECTION AND ANALYSIS: Two reviewers independently checked titles and abstracts identified by the searches and full text copies of all papers of potential relevance were considered. Trials were graded for methodological quality using the Cochrane approach. Data extraction was performed in a standardised manner. Meta-analysis was neither possible, nor considered appropriate, because of the heterogeneity of the patient groups studied; a narrative overview of the results is therefore presented. MAIN RESULTS: Four trials satisfied the inclusion criteria, all of which were small and of poor quality. Two trials investigated the efficacy of acaricides, a third investigated the role of high-efficiency particulate air (HEPA) filters, whilst a fourth investigated the efficacy of a bedroom environmental control program that comprised use of a barrier mattress cover, fortnightly washing of bed covers, removal of soft furnishings and daily cleaning. Each of the four trials showed the interventions to result in significant reductions in house dust mite load when compared with control. Trial results suggest that the interventions may be effective in reducing some rhinitis symptoms, though it is not possible to provide a reliable summary estimate about the magnitude of such symptom reduction. No serious adverse effects were reported from the interventions. REVIEWER'S CONCLUSIONS: Trials to date have been small and of poor methodological quality making it difficult to offer any definitive recommendations on the role, if any, of house dust mite avoidance measures in the management of house dust mite sensitive perennial allergic rhinitis. The results of these studies suggest that interventions designed to reduce house dust mite exposure in patients with house dust mite allergic perennial rhinitis may be of some benefit in reducing rhinitis symptoms. Data at present is only available for acaricides, HEPA filters and a bedroom-based environmental control program; therefore, if considered appropriate, these should be the interventions of choice.

Animals↗
PubMed2001

A critical evaluation of the scientific basis of the MAK Commission's new general threshold limit values for dust.

In 1997, the German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area set a new MAK value ("Maximale Arbeitsplatz-Konzentration") governing worker exposures to general airborne dust. The new values limit worker dust exposures to concentrations not exceeding 1.5 mg/m3 for respirable dust and 4 mg/m3 for inhalable dust, and are substantially lower than corresponding standards in other western industrialized nations. The purpose of this document is to critically review the science behind the MAK Commission's new threshold limit value standards. The Commission relied heavily upon a re-analysis of data from the Deutsche Forschungsgemeinschaft (DFG) Chronic Bronchitis study (1965-1977). We have reservations about the scientific merit of the DFG study and the validity of data used as the basis for establishing a new MAK value for dust. In particular: (1) Assessing the potential role of inert dust in the development of chronic bronchitis in worker cohorts with extremely high cigarette smoking prevalences is scientifically implausible. (2) It is unlikely that the dust in the industries studied, including steel works, foundries and cement works, was in fact "inert", and any effects of the dust on chronic bronchitis rates may have been increased by the presence of free crystalline silica and other toxic agents. (3) The study made use of area- rather than personal-exposure monitoring, thereby correlating the prevalence of chronic bronchitis with lower dust exposure levels than actually existed and significantly overstating the health effects of the dust exposures. (4) Inappropriate statistical methods were used to estimate threshold limit values. Results of three additional epidemiological studies are cited as providing evidence of chronic lung effects due to insoluble dust exposure. All three studies suffer from extremely poor documentation of the study methodology, particularly regarding lung function testing, and they provide little evidence that exposure to insoluble non-fibrogenic dusts leads to chronic lung obstruction. In summary, it is our opinion that the studies evaluated by the MAK Commission and the methods used do not provide the scientific basis to support the lower threshold limit values for dust. We recommend that an appropriate prospective morbidity study be conducted to address the concerns detailed in this critical examination.

Bronchitis↗
PubMed2004

Cytotoxic effect and role of exogenous antioxidants in carpet dust mediated toxicity in rat hepatocytes in vitro.

Carpet industries bear a great deal of economic and commercial significance in India. In order to safe guard the workers against the health hazards caused by dust in their occupational environment; it necessitates studying the biological importance of these dusts. The present study was designed to investigate the toxicity of carpet dust (knotted and tuffted) on isolated rat hepatocytes. The hepatocytes were isolated by collagenase perfusion method and cells were incubated with different concentration of carpet dust (100-5000 microg/10(6) cells) with various time (30-180 min) intervals. An exogenous antioxidant vitamin-E also used to find out the role of antioxidants and free radical production in carpet dust mediated toxicity. Cell viability by trypan blue exclusion and leakage of enzyme lactate dehydrogenase (LDH) were determined. Reduced glutathione (GSH), formation of thiobarbituric acid reactive substance (TBARS) were also measured. A significant decrease in the cell viability was observed after 60, 180 min upon incubation with tuffted carpet dust, while knotted carpet dust caused a significant decrease in the viability after 180 min. LDH leakage was parallel to the cell viability. Thiobarbituric acid reactive substance was significantly increased at 30 and 60 min with carpet dust treated hepatocytes. Dust at 1000 and 5000 microg dose level showed significantly increased formation of TBARS at 30 min incubation. However, when hepatocytes were co-incubated with carpet dust and Vit-E (10, 15 microM), a significant decrease in LDH release and TBARS production was observed while 15 microM Vit-E showed an enhanced protection than 10 microM Vit-E treated hepatocytes. The effect of carpet dust on cell viability, LDH leakage, TBARS production, GSH depletion was time and dose-dependent. Moreover, we observed that tuffted carpet dust causes greater effect than knotted one on the above mentioned parameters. Our studies also revealed that Vit-E in culture media diminishes the carpet dust mediated toxicity.

Animals↗
PubMed2006

Trans boundary transport of pollutants by atmospheric mineral dust.

The transport of anthropogenic pollution by desert dust in the Eastern Mediterranean region was studied by analyzing major and trace element composition, organic species, and Pb isotope ratios in suspended dust samples collected in Jerusalem, Israel. Dust storms in this region are associated with four distinct synoptic conditions (Red Sea Trough (RS), Eastern High (EH), Sharav Cyclone (SC), and Cold Depression (Cyprus low, CD)) that carry dust mostly from North African (SC, CD, EH) and Arabian and Syrian (RS, EH) deserts. Substantial contamination of dust particles by Pb, Cu, Zn, and Ni is observed, while other elements (Na, Ca, Mg, Mn, Sr, Rb, REE, U, and Th) display natural concentrations. Sequential extraction of the abovementioned elements from the dust samples shows that the carbonate and sorbed fractions contain most of the pollution, yet the Al-silicate fraction is also contaminated, implying that soils and sediments in the source terrains of the dust are already polluted. We identified the pollutant sources by using Pb isotopes. It appears that before the beginning of the dust storm, the pollutants in the collected samples are dominated by local sources but with the arrival of dust from North Africa, the proportion of foreign pollutants increases. Organic pollutants exhibit behavior similar and complementary to that of the inorganic tracers, attesting to the importance of anthropogenic-pollutant addition en route of the dust from its remote sources. Pollution of suspended dust is observed under all synoptic conditions, yet it appears that easterly winds carry higher proportions of local pollution and westerly winds carry pollution emitted in the Cairo basin. Therefore, pollution transport by mineral dust should be accounted for in environmental models and in assessing the health-related effects of mineral dust.

Air Pollutants↗
PubMed2002

Biological monitoring of wood dust exposure in nasal lavage by high-performance liquid chromatography.

A high-performance liquid chromatography (HPLC) method for biomonitoring of occupational wood dust exposure based on nasal lavage as a biomonitoring matrix was developed. Gallic acid (GA) was chosen as the indicator compound for oak dust exposure. From the chromatographic profile of ash dust, four peaks were chosen as indicator compounds. Phenolic indicator compounds were analysed by HPLC. Personal dust samples and corresponding nasal lavage samples were collected from 16 workers exposed to oak dust and six to ash dust. The dust concentrations in the workers' breathing zone varied between 0.7 and 13.8 mg m(-3). The indicators revealed the nature of the wood dust inhaled. For the workers who did not use respirators, the correlation between the dust and corresponding indicator compound in their nasal lavage was significant; r2 = 0.59 (n = 12) for oak dust and r2 = 0.58 (n = 6) for ash dust, respectively. Further, the correlation for oak dust workers who used respirators was r = 0.67 (n = 4). Nasal lavage sampling and HPLC analysis of polyphenol indicator compounds are promising tools for measuring wood dust exposure. Although further validation is necessary, determination of the individual dose may prove invaluable in prospective epidemiological studies.

Chromatography, High Pressure Liquid↗
PubMed1998

House dust mite antigen exposure of patients with atopic dermatitis of psoriasis.

We studied the amount of house dust antigen in the beds of 55 patients with atopic dermatitis, eleven patients with psoriasis and ten healthy volunteers using a commercial ELISA which can determine the amount of antigen from Dermatophagoides pteronyssinus, D. farinae and D. microseras expressed as nanogram (ng) antigen per gram of house dust. The World Health Organization has indicated that 10,000 ng house dust mite antigen per gram house dust can elicit an asthma attack in IgE-sensitized patients with asthma bronchiale. There are no recommendations for patients with atopic eczema. We observed no statistical significant differences between each group concerning the amount of house dust found in the beds or the amount of house dust mite antigen. However, there were very wide variations. Twenty-seven percent (15/55) of patients with atopic dermatitis and 27% (3/11) of psoriasis patients had levels of house dust mite antigen above 10,000 ng per gram of house dust compared with healthy volunteers (1/10). Half of the patients had a type I allergy to house dust mite antigen using prick tests. This group had a total serum IgE of 2,034 kU/I (median value) compared to 301 kU/I in the group without type I allergy to house dust mite antigen (p < 0.01). The exposure to house dust mite antigen was similar in the two groups. We conclude that only 1/4 of patients with atopic dermatitis are exposed to high levels of house dust mite antigen in their bed environment equal to what is found for patients with another scaling disorder (psoriasis). Patients who have an increased serum IgE have significantly increased type I allergy to house dust mite antigen even though their exposure is not different from patients with low IgE.

Adult↗