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At least 19 recordsLinked to original sources
PubMed2000

House dust mite control measures for asthma.

BACKGROUND: The major allergen in house dust comes from mites. Chemical, physical and combined methods of reducing mite allergen levels are intended to reduce asthma symptoms in people who are sensitive to house dust mites. OBJECTIVES: The objective of this review was to assess the effects of reducing exposure to house dust mite antigens in the homes of mite-sensitive asthmatics. SEARCH STRATEGY: We searched the Cochrane Airways Group trials register, checked reference lists of articles and hand-searched Respiration (1980 to 1996) and Clinical and Experimental Allergy (1980 to 1996). SELECTION CRITERIA: Randomised trials of mite control measures in asthmatic people known to be sensitive to house dust mites. DATA COLLECTION AND ANALYSIS: Two reviewers applied the trial inclusion criteria and extracted the data independently. One reviewer applied the trial quality assessment criteria. Study authors were contacted to clarify information. MAIN RESULTS: Twenty-three trials were included, with four trials awaiting assessment. There was little difference in improvement of asthma between people in experimental groups compared to control groups (odds ratio 1.2, 95% confidence interval 0.66 to 2.18). Asthma symptom scores were also similar for the experimental and control groups (standardised mean difference -0. 06, 95% confidence interval -0.54 to 0.41). These scores showed a high degree of heterogeneity. No significant difference was noted for medication usage (standardised mean difference -0.14, 95% confidence interval -0.43 to 0.15). Peak flow in the morning showed no significant difference between the experimental and the control groups (standardised mean difference -0.03, 95% confidence interval -0.25 to 0.19). REVIEWER'S CONCLUSIONS: Current chemical and physical methods aimed at reducing exposure to house dust mite allergens seem to be ineffective and cannot be recommended as prophylaxis for mite sensitive asthmatics.

Allergens↗
PubMed2000

[Investigation of the mite fauna content of dust samples collected from pig and poultry farms. Report of the first finding in Western Europe of the house-dust mite Dermatophagoides evansi in dust from poultry houses].

Mites can be important sources of airborne allergens, especially on farms. Two dust samples from pig farms and three dust samples from poultry farms were investigated for mites. House-dust mites were present in the poultry-dust samples, but not in the pig-dust samples. Furthermore, storage mites and predatory mites also were found in the poultry-dust samples. Specifically, the house-dust mite Dermatophagoides evansi was found in the dust samples from two poultry farms. Subsequently, a dust sample was collected from five other poultry farms. Again, D. evansi was present in dust from these farms. This is the first time that D. evansi is reported in dust from poultry farms in Western Europe outside Norway. If D. evansi cross-reacts with other Dermatophagoides spp., then poultry farmers and their families, but also other professionals working in the poultry industry, such as veterinarians, may be exposed to house-dust mites with potential clinical consequences, both domestic and occupational.

Allergens↗
PubMedDate not supplied

[Allergens of domestic dust. III. Comparison of the cutaneous responses to an extract of total dust, to an extract of D. pteronyssinus and to an extract of dissacharinized dust].

A study of the coefficient of correlation has been made, based on cutaneous response and by intradermal means, between household dust from Barcelona diluted to a strength of 1/1,000 and an extract of D. Pteronyssinus and its medium of culture, diluted to a strength of 1/1,000,000. This study was effected to a group of thirty-three children with allergic asthma, sensitive to household dust, with a resultant value of r = 0.94 (p less than 0.001). In the same way, thirty-six children with the same characteristics, the correlations between the same extracts and an extract of dust without mites has been studied. Using Spiekma's technic, this dust was obtained through successive sifts gathered in a case under the inferior sifter. Of the mentioned dust, two equal fractions were made, one to confirm the absence of mites (Spiekma's technique) and the other to realize the extract, preparing the dilutions 1/1,000 and 1/1,000,000. With the dilution 1/1,000, the value is r = 1 (p less than 0.001) for the domestic dust and of r = 0.94 (p less than 0.001) for the D. Pteronyssinus. In sixteen of the above mentioned children, the study was repeated with the same extract, using the dilution of 1/1,000,000, and the values obtained were of r for household dust of 0.004 (p less than 0.55) and for D. Pteronyssinus of 0.016 (p less than 0.55). In twenty-one of these children, unmited dust and the extract of the way of cultivation (9 parts of human skin scales and 1 part of Sacharomyces) was compared, both diluted to 1/1,000. The value obtained was of r = 0.89 (p less than 0.001). Taking these results into consideration, it seems that D. Pteronyssinus is the most powerful allergene of dust, but the possible role of fecal pellets, product of mite excretion and of human skin scales should be considered as minor allergenes. The human skin scales emphasize their role in this case, and even though good correlation is obtained, we need to use concentrations a thousand times bigger than the D. Pteronyssinus. One can think of it being the same antigen, but the study made previously between uncultivated mites in human skin scales and these in concentrations of the same potence, has been of 0.31, which leads us to think that it is not the same antigene. Finally we consider that in some conditions, it is possible that other antigenes participate in the genesis of dust allergic (fecal pellets, human skin scales), but the antigenic power is very low.

Acari↗
PubMed1990

[Dust levels and dust-induced diseases in the main dust-producing industries].

The data on airborne dust and occupational disease in the main dust-related industries of the People's Republic of Bulgaria are generalized and analyzed for a period of 15 years. In the ore producing industry is established a stability in the concentration of total and respirable dust 1-2 TWA concentrations and decrease of silica content in dust. The highest occupational hazard is registered in diggers. The levels of TWA total and respirable dust and silica concentrations in the other underground mines as well as in the overground industries are strongly variable and high. Silicosis is still in the first place among dust-related diseases, but mainly among miners of advanced age. The newly detected other pneumoconiosis, asbestosis, mixed pneumoconiosis are already more than the cases of silicotuberculosis. An essential part is taken by the newly detected diffusive pneumosclerosis and dust bronchitis. The distribution of the newly detected occupational lung diseases is studied according to branches of industry.

Bulgaria↗
PubMed2001

Effect of nonadiabaticity of dust charge variation on dust acoustic waves: generation of dust acoustic shock waves.

The effect of nonadiabaticity of dust charge variation arising due to small nonzero values of tau(ch)/tau(d) has been studied where tau(ch) and tau(d) are the dust charging and dust hydrodynamical time scales on the nonlinear propagation of dust acoustic waves. Analytical investigation shows that the propagation of a small amplitude wave is governed by a Korteweg-de Vries (KdV) Burger equation. Notwithstanding the soliton decay, the "soliton mass" is conserved, but the dissipative term leads to the development of a noise tail. Nonadiabaticity generated dissipative effect causes the generation of a dust acoustic shock wave having oscillatory behavior on the downstream side. Numerical investigations reveal that the propagation of a large amplitude dust acoustic shock wave with dust density enhancement may occur only for Mach numbers lying between a minimum and a maximum value whose dependence on the dusty plasma parameters is presented.

Journal Article↗
PubMed1983

Dust-free bedrooms in the treatment of asthmatic children with house dust or house dust mite allergy: a controlled trial.

Twenty asthmatic children with prick tests positive for house dust or house dust mites were allocated to two groups that were matched for severity. One group was provided with zippered vinyl covers for pillows, mattresses, and box springs, and instructions for making the bedroom as easy to keep clean as a hospital ward; the other group was not. At the end of a 1-month study period, there was a marked and statistically significant difference in symptoms and signs of asthma between the two groups. Those with a dust-free bedroom had fewer days on which wheezing was observed, medication was given, or an abnormally low peak expiratory flow rate was recorded. Bronchial tolerance to aerosolized histamine significantly improved in the group whose bedrooms had been modified. A dust-free bedroom diminishes bronchial irritability and is a practical and effective method for decreasing asthma in children with house dust or house dust mite allergy.

Asthma↗
PubMed2003

Distribution of house dust mite allergen: comparing house dust mite allergen levels in dust samples collected from different sites on living room floors with smooth coverings.

BACKGROUND: The distribution of house dust mite allergen (Der p1) in living rooms with smooth floor coverings, as measured in the middle compared with the border of the floor was investigated. It was hypothesized that activity causes displacement of Der p1, from the middle towards the border. METHODS: Dust samples from the middle and border of 50 floors with smooth coverings were collected and analysed on Der p1 content in a standardized way. RESULTS: The Der p1 exposure expressed as per unit area (ng/m2) showed that border samples contained significantly more Der p1 compared with middle samples (median: 2.57 vs 0.27, respectively, P = 0.023). Presence of pets and presence of more than two inhabitants increased the difference. When expressed as per unit weight of dust (ng/g), significant differences were only detected when comparing Der p1 content of samples collected in households with three or more inhabitants [median: 2 (border) vs 53 (middle), respectively; P = 0.035]. CONCLUSIONS: The Der p1 is unequally distributed on living room floors with smooth coverings, most likely because of displacement of dust from the middle towards the border due to activity. Expression as ng/g of dust and ng/m2 could not obviously be interchangeable.

Animals↗
PubMed1992

Dust from carpeted and smooth floors. V. Cat (Fel d I) and mite (Der p I and Der f I) allergen levels in school dust. Demonstration of the basophil histamine release induced by dust from classrooms.

Sixty dust samples from schools in Norway were analysed for major allergens from cat and mite after sampling with the regularly used vacuum cleaners for 5 days and with a new model vacuum cleaner for 10 days, respectively. The major feline allergen Felis domesticus allergen I (Fel d I) was detected in all the classrooms, with ranges from 12 to 16,840 ng/m2 floor area. The mean Fel d I concentration was about 11 times higher per unit area carpeted floors as compared with smooth floors after the 10 days sampling period. Mite allergens Dermatophagoides pteronyssinus allergen I (Der p I) and Dermatophagoides farinae allergen I (Der f I) were detected in very low concentrations, with ranges from < 1 ng to 104 ng/m2 floor area. These findings suggest that the school is a protective environment against mite infestation, while the prevalence of cat allergens in classrooms seems higher than previously assumed. Basophil histamine release was measured after provocation with 20 dust extracts from 10 different schools. In nine of the 10 schools examined, the basophil histamine release caused by challenge with carpet dust was higher than the corresponding release with smooth floor dust. The calculated floor areas in each school in which dust led to 15% histamine release were from 2 to 55 times larger for smooth floors compared with carpeted floors. These results emphasize previous findings regarding higher allergen concentrations in classrooms with carpeted floors.

Allergens↗
PubMed1989

[Dust lung or dust-induced lung disease ( discussion on chronic dust-induced lung disease)].

The comment on the article by D. M. Zislin (Occupational Hygiene and Industrial Diseases, 1988, N 10) is presented. Proceeding from the author's own experience and literary data, the main statement of D. M. Zislin disputing the concept of dust pulmonary disease (DPD) in the modern occupational pulmonology, is analyzed. The common cause of pneumoconiosis and dust bronchitis has been identified as fibrogenic dust, allergic, carcinogenic and toxic characteristics of which can be only condition affecting the disease clinical character. The article shows that neither generality, nor the differences in the functional changes of external respiration can serve as a convincing argument for or against the existence of the concept of DPD. Modern histomorphologic studies give evidence that low-fibrogenic dusts practically simultaneously cause the onset of the pathologic process both in the interstitial tissue and in the bronchi, the outcome of the process being diffuse pneumosclerosis. The concept of DPD caused by low-fibrogenic dusts has been substantiated on the basis of common etiology and similar pathogenetic, clinical and functional manifestations.

Bronchitis↗
PubMed2004

Organic dusts and disease: a continuous research challenge.

Research on organic dust during recent years has revealed major clinical effects and some causative agents. Many of the symptoms reported are caused by an inflammation in the airways, characterized by a neutrophil response. This condition can cause a non-allergic asthma. There are also reactions characterized by lymphocyte accumulation and by specific IgE antibody formation. Causative agents identified as bacterial endotoxins, molds, and different allergens.

Asthma↗
PubMed2005

A pilot study of the measurement and control of deep dust, surface dust, and lead in 10 old carpets using the 3-spot test while vacuuming.

This pilot study measured and examined the relationship between surface dust, deep dust, lead (Pb), and the 3-spot test during vacuuming of carpets. The 3-spot test measures the total time in seconds for the indicator light on a Hoover vacuum with dirt detector (HVDD) to turn from red to green on three spots 3 feet apart at least 4 feet from an entrance door. Ten older carpets were sampled in the Seattle area by using the following: (1) a 3-spot test to estimate the deep dust; (2) measuring the surface dust in g/m(2) with the High-Volume Small Simplified Surface Sampler; (3) vacuuming with an HVDD to extract a portion of the deep dust in g/m(2); and (4) repeating this cycle of a 3-spot test, surface dust sample, and deep dust sample until the clean-carpet criteria was reached. Dust particles <150 mum were analyzed for Pb. The surface dust, deep dust, and dust collection rate (g/min) decreased rapidly at first and then much more slowly as vacuuming continued. The initial 3-spot test ranged from 12 to 110 seconds (median 40). The starting surface dust loading was 0.7 to 21.1 g/m(2) (median 2.9 g/m(2)), and it decreased by 84% to 99% when the deep dust was removed. Total dust-the sum of the surface dust and deep dust-ranged from 8.3 to 465 g/m(2) (median 63.2 g/m(2)). It took from 2.3 to 92 min/m(2) (median of 7.5 min/m(2)) to remove the total dust. The starting dust collection rate of 3.8 to 37 g/min decreased to final rates of 0.5 to 4.3 g/min. The 3-spot test (seconds) correlated with total dust (g/m(2)) (r = 0.63, p = 0.037) and cleaning time (min/m(2)) (r = 0.50, p = 0.12) when the data were log transformed. This study supports the utility of the 3-spot test. It tends to provide families and professional carpet cleaners with a quick and low-cost estimate of the deep dust present and the time required to clean carpets as well as indicating when the carpet is clean. Deep dust tends to accumulate in older carpets and becomes surface and airborne dust after activity on a carpet. Monitoring and removing the deep dust in old carpets may decrease the exposure of infants and sensitive adults to Pb, allergen, and other pollutants in house dust.

Dust↗
PubMed2004

The influence of exterior dust and soil lead on interior dust lead levels in housing that had undergone lead-based paint hazard control.

To aid in understanding the contribution of exterior dust/soil lead to postintervention interior dust lead, a subset of housing from the HUD Lead-Based Paint Hazard Control Grant Program Evaluation was selected for study. Housing from 12 state and local governments was included. Exterior entry and street dust samples were obtained by a vacuum method, and soil samples were building perimeter core composites. Interior dust wipe lead data (microg/ft(2)) and paint lead data (mg/cm(2)) were also available for each of the dwelling units and included in the modeling. Results from 541 dwelling units revealed a wide range of exterior dust and soil lead levels, within and between grantees. Minimum and maximum geometric mean lead levels, by grantee, were 126 and 14400 microg/ft(2) for exterior entry dust; 325 and 4610 microg/ft(2) for street dust; and, for soil concentration, 383 and 2640 ppm. Geometric mean exterior entry dust lead concentration (1641 ppm) was almost four times as high as street dust lead concentration (431 ppm), suggesting that lead dust near housing was often a source of street dust lead. Geometric mean exterior entry dust lead loading was more than four times as high as window trough dust lead loading and more than an order of magnitude higher than interior entry dust lead loading. Statistical modeling revealed pathways from exterior entry dust lead loading to loadings on interior entryway floors, other interior floors, and windowsills. Paint lead was found to influence exterior entry dust lead. Results of this study show that housing where soil lead hazard control activities had been performed had lower postintervention exterior entry, interior entry floor, windowsills, and other floor dust loading levels. Soil was not present for almost half the buildings. Statistical analysis revealed that exterior strategy influenced soil lead concentration, and soil lead concentration influenced street dust lead loading. This study represents one of the few where an impact of soil treatments on dust lead levels within the housing has been documented and may represent the first where an impact on exterior entry dust lead has been found. The inclusion of measures to mitigate the role of exterior sources in lead hazard control programs needs consideration.

Dust↗
PubMed2002

Airborne dust and allergen generation during dusting with and without spray polish.

BACKGROUND: Dusting is a commonly used method for dust removal from surfaces in the home. However, the process of dusting may contribute to airborne dust levels by disturbing dust particles from a surface and failing to remove it from the indoor environment. OBJECTIVE: We sought to measure the quantity of allergen-laden dust disturbed into the air during dusting and discover whether applying spray polish to either the dusty surface or the cleaning cloth reduced this amount. METHODS: A common furniture polish was tested for its ability to prevent dust particles and major house dust mite (Der p 1) or major cat (Fel d 1) allergen from becoming airborne during dusting. Tests were completed with a repeatable mechanized dusting procedure with polish sprayed onto either a cleaning cloth or directly onto a surface, and this was compared with a control procedure with a standard duster. Airborne dust was measured with an air-particle counter and by means of anti-Der p 1 or anti-Fel d 1 ELISA. RESULTS: Considerable quantities of dust became airborne during dusting. When polish was sprayed onto the cleaning cloth, the concentration of airborne dust particles was reduced by a mean of 83.4%, house dust mite allergen by 50.3%, and cat allergen by 57.4% when compared with dry-cloth controls. Spraying polish directly onto the surface was even more effective at reducing the generation of airborne particles (92.9%) and allergens (Der p 1 by > or =95% to below the sensitivity of the ELISA and Fel d 1 by 95%). All reductions were significant when compared with dry-cloth controls (P <.01, Mann-Whitney U test). CONCLUSIONS: This study showed that application of a polish spray to either the surface or the cloth during dusting greatly reduced dust and allergen evolution into the air, which should reduce exposure to airborne allergens in the home.

Air↗
PubMed2005

Predicting historical dust and wood dust exposure in sawmills: model development and validation.

Nonspecific dust measurements are used as a surrogate for wood dust exposure in sawmills. However, the wood dust component of dust has been found to vary by job and work area. Thus, the use of nonspecific dust exposure levels in epidemiologic studies may introduce exposure misclassification when assessing wood-related health effects. To improve exposure assessment in a retrospective cohort of 28,000 sawmill workers, we developed and evaluated the validity of two empirical models of exposure: one for nonspecific dust and one for wood dust. The dust model was constructed using 1,395 dust measurements collected in 13 sawmills for research or regulatory purposes from 1981 to 1997. Inter-sampler conversion factors were used to obtain inhalable dust equivalents if necessary. The wood dust model was constructed after applying adjustment factors to subtract nonwood components of the dust from the original measurements. The validity of the two models was tested against measurements (n = 213) from a technologically similar mill that was not part of the cohort study. The proportions of variability explained by the dust and wood dust models were 35% and 54%, respectively. When tested against the validation mill, the biases in the dust model were -33% for outdoor jobs and 2% for indoor jobs. The biases in the wood dust model were 2% for outdoor jobs and -3% for indoor jobs. Strong correlations were observed between the predicted and observed geometric means of jobs (0.79 and 0.70 for the dust model and wood dust model, respectively). Testing the validity of predictive models examines the generalizability of the models. The low overall bias, especially in the wood-specific model, increases our confidence in the use of these models for all sawmills to assess both nonspecific particulate and wood-related health effects in the historical cohort study.

Cohort Studies↗
PubMed1997

The relation between subjective dust exposure estimates and quantitative dust exposure measurements in California agriculture.

Measuring exposure levels for epidemiologic research is time consuming and expensive and therefore subjective exposure estimates are sometimes used instead. In this study we related the subjective dust exposure estimates of workers in California agriculture to personal dust exposure measurements. One hundred and twenty-four observations were available for comparison of subjective dust estimates and inhalable dust measurements and 129 observations for comparison of subjective dust estimates and respirable dust measurements. Individual subjective dust estimates showed weak to moderate correlations with measured dust concentrations for both the inhalable (Rs = 0.67) and respirable dust fraction (Rs = 0.36). The within-worker reliability coefficients were low (0.2 and 0.1, respectively). Grouped subjective dust estimates performed better and showed a consistent increase with average measured dust levels, in particular for the inhalable dust fraction (R2 = 0.81). Age, the number of years working in agriculture, education level, the presence of any respiratory symptoms, and the language of the questionnaire did not have a significant independent effect on the relationship between measured dust levels and subjective dust estimates. California agricultural workers appear to be reasonably good at estimating inhalable dust levels, in particular if an average of many different workers is taken, but they are unable to provide good estimates of respirable dust levels. Measuring dust levels remains the preferred option.

Agriculture↗
PubMed2004

Theory of dust and dust-void structures in the presence of the ion diffusion.

A dust void is a dust-free region inside the dust cloud that often develops for conditions relevant to plasma processing discharges and complex plasma experiments. A distinctive feature of the void is a sharp boundary between the dust and dust-free regions; this is manifested especially clear when dissipation in the plasma is small and discontinuity of the dust number density appear. Here, the structure of the dust void boundary and the distribution of the dust and plasma parameters in the dust structure bordering the void is analyzed taking into account effects of dissipation due to the ion diffusion on plasma neutrals. The sharp boundary between the dust and void regions exists also in the presence of the ion diffusion; however, only derivatives of the dust density, dust charge, electron density and electric field are discontinuous at the void boundaries, while the functions themselves as well as derivatives of the ion drift velocity and the ion density are continuous. Numerical calculations demonstrate various sorts of diffusive dust void structures; the possibility of singularities in the balance equations caused by the diffusion process inside the dust structures is investigated. These singularities can be responsible for a new type of shocklike structures. Other structures are typically self-organized to eliminate the singularities. Numerical computations in this case demonstrate a set of thin dust layers separated by high density thin dust clouds similar to the multiple-layer dust structures observed in the laboratory and in the upper ionosphere. The possibility for existence of a few equilibrium positions of the void boundary is discussed.

Journal Article↗
PubMed2006

Assessment of personal direct-reading dust monitors for the measurement of airborne inhalable dust.

The performances of five portable direct-reading dust monitors were investigated in a wind tunnel for a range of industrial dusts and three sizes of aluminium oxide test dust to mainly determine their suitability for measuring the inhalable fraction of airborne dust in workplaces. The instruments tested were Split 2 (SKC Ltd), Sidepak (TSI Inc.), Dataram (Thermo Electron Ltd), PDS-2 (Sibata Scientific Technology Ltd) and the Respicon TM (Hund Ltd). The instruments' responses were compared with reference dust samplers. These were the IOM sampler for the inhalable fraction and the Casella cyclone sampler for the respirable fraction. All instruments are predominantly responsive to and are designed to measure particles in the respirable size range, although two of the instruments, the Split 2 and Respicon TM, are claimed to be capable of measuring inhalable-sized particles. For the purpose of the tests, major modifications to an existing wind tunnel dust injection system were made to facilitate the generation of uniform concentrations of large inhalable-sized dust particles at low air velocities. Each monitor greatly underestimated the measurement of inhalable concentration for all the dusts tested, although the linearity was good over a wide range of concentrations for any particular size distribution of dust. However, their calibration factors, defined as the ratio of reference inhalable concentration to monitor concentration, were especially sensitive to changes in particle size as the response of the instruments decreased rapidly with increasing particle size. The monitors generally overestimated the measurement of respirable dust concentration by up to a factor of about 2, apart from the PDS-2, which underestimated it by a factor of up to 3. There was, however, a great deal more scatter in the reference respirable concentration measurements owing to the collection of small dust samples. Therefore, monitor linearity and effects of monitor response to changes in particle size could not be accurately investigated for the respirable fraction. The sampling head of the Split 2 monitor incorporates an IOM inlet and filter to gravimetrically collect the inhalable fraction of airborne dust. This can give a concurrent reference measure of inhalable airborne dust concentration. However, poor sealing within the sampling head resulted in some of the sampled dust not reaching the backup filter. This resulted in the Split 2 underestimating the reference inhalable dust concentration, which meant that it could not be accurately used as a calibration standard. Communications with the manufacturers have since revealed that the sampling head has recently been redesigned in order to improve the seal and eliminate leakage. The Respicon sampler gravimetrically underestimated the inhalable dust concentration, and did so increasingly as the particle size increased.

Air Pollutants, Occupational↗