Morphology of silicon carbide (SiC) fibres from the Norwegian SiC industry has been studied by scanning electron microscopy (SEM). The fibres are an unwanted side-product in SiC production. They represent a probable cause of the observed increased occurrence of lung diseases among SiC workers. The main aim of this work is to give a detailed description of the morphological variation of the fibres. Furthermore, it is important to study the occurrence of various morphological types with respect to job types and process parameters. SiC fibres accounted for >90% of all fibres observed. Eight categories of SiC fibres are described based on their morphology. The most frequent fibre category had a smooth surface and accounted for more than half of the observed SiC fibres. The diameter distributions of the eight fibre types were significantly different except for two of the categories. More than 99% of the SiC fibres observed were
BACKGROUND: The reasons for the increasing incidence of and strong male predominance in patients with oesophageal and cardia adenocarcinoma remain unclear. The authors hypothesised that airborne occupational exposures in male dominated industries might contribute. METHODS: In a nationwide Swedish population based case control study, 189 and 262 cases of oesophageal and cardia adenocarcinoma respectively, 167 cases of oesophageal squamous cell carcinoma, and 820 frequency matched controls underwent personal interviews. Based on each study participant's lifetime occupational history the authors assessed cumulative airborne occupational exposure for 10 agents, analysed individually and combined, by a deterministic additive model including probability, frequency, and intensity. Furthermore, occupations and industries of longest duration were analysed. Relative risks were estimated by odds ratios (OR), with 95% confidence intervals (CI), using conditional logistic regression, adjusted for potential confounders. RESULTS: Tendencies of positive associations were found between high exposure to pesticides and risk of oesophageal (OR 2.3 (95% CI 0.9 to 5.7)) and cardia adenocarcinoma (OR 2.1 (95% CI 1.0 to 4.6)). Among workers highly exposed to particular agents, a tendency of an increased risk of oesophageal squamous cell carcinoma was found. There was a twofold increased risk of oesophageal squamous cell carcinoma among concrete and construction workers (OR 2.2 (95% CI 1.1 to 4.2)) and a nearly fourfold increased risk of cardia adenocarcinoma among workers within the motor vehicle industry (OR 3.9 (95% CI 1.5 to 10.4)). An increased risk of oesophageal squamous cell carcinoma (OR 3.9 (95% CI 1.2 to 12.5)), and a tendency of an increased risk of cardia adenocarcinoma (OR 2.8 (95% CI 0.9 to 8.5)), were identified among hotel and restaurant workers. CONCLUSIONS: Specific airborne occupational exposures do not seem to be of major importance in the aetiology of oesophageal or cardia adenocarcinoma and are unlikely to contribute to the increasing incidence or the male predominance.
Epidemiological studies have demonstrated associations between short-term increases in outdoor air pollution concentrations and adverse cardiovascular effects, including cardiac mortality and hospitalizations. One possible mechanism behind this association is that air pollution exposure increases the risk of developing a cardiac arrhythmia. To investigate this hypothesis, dates of implantable cardioverter defibrillator (ICD) discharges were abstracted from patient records in patients attending the two ICD clinics in Vancouver, BC, for the years 1997-2000. Daily outdoor air pollutant concentrations and daily meteorological data from the Vancouver region were obtained for the same 4-yr period. Generalized estimating equations were used to assess the association between short-term increases in air pollutant concentrations and ICD discharges while controlling for temporal trends, meteorology, and serial correlation in the data. Air pollution concentrations in the Vancouver region were relatively low from 1997 to 2000, as expected. In the 50 patients who resided within the Vancouver region and who experienced at least 1 ICD discharge during the period of follow-up, no significant associations between increased air pollution concentrations and increased ICD discharges were present. When the patient sample was restricted to the 16 patients who had at least 6 months of follow-up and experienced a rate of at least 2 days with ICD discharges per year, there was a statistically significant association between increased sulfur dioxide (SO(2)) concentration and ICD discharge 2 days after the SO(2) increase. When stratified by season, no associations between increased air pollutant concentrations and increased risk of ICD discharge were observed in the summer, although for several pollutants, concentration increases were associated with a decrease in ICD discharges. In the winter, increased SO(2) concentrations again were seen to be associated with increased risk of ICD discharge, at both 2 and 3 days following increases in SO(2) concentrations. These findings provide no compelling evidence that short-term increases in relatively low concentrations of outdoor air pollutants have an adverse effect on individuals at risk of cardiac arrhythmias. The findings regarding SO(2) are difficult to interpret. They may be chance findings. Alternatively, given the very low concentrations of SO(2) that were present in Vancouver, SO(2) may have been serving as a surrogate measure of other environmental or meteorological factors.
Otitis media (OM) is one of the most common early childhood infections, resulting in an enormous economic burden to the health care system through unscheduled doctor visits and antibiotic prescriptions.
The objective of this study was to investigate the potential association between ambient air pollution exposure and emergency department (ED) visits for OM.
Ten years of ED data were obtained from Edmonton, Alberta, Canada, and linked to levels of air pollution: carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3), sulfur dioxide, and particulate matter (PM) of median aerometric diameter
Cites: An Pediatr (Barc). 2004 Feb;60(2):133-814757016
Cites: Vaccine. 2008 Dec 23;26 Suppl 7:G5-1019094935
In the paper there are presented data on the hygienic evaluation of the air pollution in the city of Kazan as a risk factor for the public health. The largest contribution to the air pollution in the city of Kazan was shown to be endowed by vehicles. The proportion of vehicle emissions in total emissions in the city in 2012 amounted to 71.4%. According to monitoring data the average annual concentrations of pollutant substances in 2012 exceeded the hygienic standards for benzo (a) pyrene--in 2.5 times, soot--2.2 times, nitrogen dioxide--1.8 times, formaldehyde--1.7 times. The risk of inhalation exposure is assessed as high, the greatest contribution to the risk is contributed by suspended matter PM2.5, soot and nitrogen dioxide.
Trimellitic anhydride (TMA) is a cause of asthma in man. Dose-dependent TMA-specific IgE, histopathology, and airway responses after sensitization by inhalation were examined in the Brown Norway rat. Rats were exposed to 0.04, 0.4, 4, or 40 mg/m3 TMA aerosol for 10 min, once a week, over 10 weeks. All lower exposures were, subsequently, rechallenged to 40 mg/m3 TMA aerosol. All rats received a sham exposure 1 week prior to the first TMA exposure. Following the sham exposure and weekly after each TMA exposure, TMA-specific IgE and both early-phase airway response (EAR) and late-phase airway response (LAR) were measured using enhanced pause (Penh). All rats sensitized by 40 mg/m3 TMA developed specific IgE, EAR, and LAR to one or more of the challenges to 40 mg/m3 TMA. TMA of 4 mg/m3 induced a much lower, but stable, specific IgE response. EAR and LAR were observed only after a 40 mg/m3 TMA rechallenge in this group, but it was much larger than that observed in the 40 mg/m3 TMA-sensitized and challenged group. Exposure-dependent histopathological changes noted included eosinophilic granulomatous interstitial pneumonia, perivascular eosinophil infiltrates, bronchial-associated lymphoid tissue hyperplasia, and peribronchiolar plasma cell infiltrates.
The objective of the study was to determine whether swine farmers continuously exposed to the farming environment react differently to acute exposure than previously unexposed nonfarmers.
Nine healthy nonfarmers, not previously exposed to a farming environment, and eight swine farmers were exposed in a swine confinement building for 3 hours while weighing pigs. Lung function measurements, methacholine challenge tests, and nasal lavages were performed before and after the exposure. Blood samples were drawn repeatedly during the exposure day. Differential cell counts and cytokine levels were analyzed in the nasal lavage fluid and blood.
The exposure levels were the same in both groups. Bronchial responsiveness to methacholine increased by a median of 4.0 (25th-75th percentiles 2.2-10.1 among the nonfarmers) and 0.7 (25th-75th percentiles 0.01-3.5 among the farmers) doubled concentration steps. The median serum levels of interleukin-6 increased from 3.8 (25th-75th percentiles
OBJECTIVES: Powder painting is an alternative to solvent-based spray painting. Powder paints may contain organic acid anhydrides (OAAs), which are irritants to the airways and may cause sensitisation. The aim of this study was to determine the prevalence of respiratory symptoms and immunological response among powder painters and to describe the exposure to OAAs. METHODS: In all, 205 subjects in 32 enterprises participated: 93 exposed and 26 formerly exposed workers in 25 powder paint shops and 86 unexposed workers. They completed a questionnaire about working conditions and symptoms and took part in a medical examination, which included a lung function test. Urine samples, for determination of two OAAs, and blood samples, for analysis of specific antibodies against the OAAs, were taken. In addition, 33 paint samples were analysed for nine OAAs. RESULTS: The powder painters reported more work-related respiratory symptoms than unexposed subjects did. The prevalence of three or more symptoms was 24% in subjects with low exposure, 44% in highly exposed individuals, 46% in formerly exposed subjects and 19% in unexposed workers. Asthma symptoms were frequent, 7%, 40%, 15% and 2%, respectively. Regression analyses of the lung volumes did not show any influence of exposure. IgG, but not IgE, against the OAAs and metabolites of OAAs was found in some subjects, but no associations with the exposure could be observed. OAAs were found in only small amounts in the paint samples. CONCLUSIONS: The exposure to organic acid anhydrides was estimated to be low, and yet, IgG antibodies to OAA were observed in some subjects. The prevalence of work-related symptoms from the eyes and the airways was relatively high among the powder painters, and these symptoms, but not the lung volumes, were clearly related to exposure. The symptoms were probably caused by irritative properties of the powder paint dust.
BACKGROUND: Some schools in Sweden offer allergen avoidance classrooms for allergic children with severe asthma. However, the measures commonly used to achieve a reduction in allergen levels have not been properly evaluated. The aim of the present prospective study was to study whether the levels of airborne cat allergen are altered after introducing feasible intervention measures in classrooms, without interfering with peoples' freedom of choice regarding pet ownership. METHODS: Twenty-five classes, including five established allergy prevention classrooms participated in the study during a school year. After one term, six classes underwent a number of intervention measures recommended by the Swedish National Institute of Public Health. Curtains, upholstery and plants were removed, bookshelves were replaced with cupboards and regular cleaning was increased. Airborne dust was collected weekly (32 weeks) using duplicate Petri dishes (n = 1574) and on six occasions using two personal air samplers in each class (n = 264). RESULTS: Airborne cat allergen levels were showing a similar variability throughout the whole study in all classes. Despite extensive measures in order to reduce allergen exposure, cat allergen levels were unaltered in the six classes after intervention. Allergen levels were not significantly lower in the established allergy prevention classes, compared with the other classes. Cat allergen levels differed, however, significantly between classes with few and many cat owners (P
The absence of IgE sensitization to allergen components in the presence of sensitization to the corresponding extract has been reported, but its clinical importance has not been studied.
To evaluate the clinical significance of IgE sensitization to three aeroallergen extracts and the corresponding components in relation to the development of respiratory disease.
A total of 467 adults participated in the European Community Respiratory Health Survey (ECRHS) II and 302 in ECRHS III, 12 years later. IgE sensitization to allergen extract and components, exhaled nitric oxide (FeNO) and bronchial responsiveness to methacholine were measured in ECRHS II. Rhinitis and asthma symptoms were questionnaire-assessed in both ECRHS II and III.
A good overall correlation was found between IgE sensitization to extract and components for cat (r = 0.83), timothy (r = 0.96) and birch (r = 0.95). However, a substantial proportion of subjects tested IgE positive for cat and timothy allergen extracts but negative for the corresponding components (48% and 21%, respectively). Subjects sensitized to both cat extract and components had higher FeNO (P = 0.008) and more bronchial responsiveness (P = 0.002) than subjects sensitized only to the extract. Further, subjects sensitized to cat components were more likely to develop asthma (P = 0.005) and rhinitis (P = 0.007) than subjects sensitized only to cat extract.
Measurement of IgE sensitization to cat allergen components would seem to have a higher clinical value than extract-based measurement, as it related better to airway inflammation and responsiveness and had a higher prognostic value for the development of asthma and rhinitis over a 12-year period.