Dust is in the air: effects of occupational exposure to mineral dust on lung function in a 9-year study

Pulmonary Functions and Oxidative Stress Biomarkers Among Silica-Exposed Foundry Workers

OBJECTIVE

To investigate the changes of the ventilatory function tests and the oxidative stress biomarkers among silica-exposed foundry workers.

METHODS

The exposed group included 70 workers in an iron foundry. The nonexposed group included 40 subjects from Kasralainy outpatient clinic. Both groups were subjected to history taking, clinical examination, chest radiograph, spirometry, urinary silica, serum malondialdehyde (MDA), glutathione peroxidase (GPx), and 8-hydroxydeoxyguanosine (8-HdG).

RESULTS

Higher urinary silica, serum MDA and serum 8-HdG, whereas lower serum GPx and ventilatory functions were detected in the exposed group compared with the controls. All parameters correlated with urinary silica. The exposed silicotic subgroup had increased work duration, urinary silica, serum MDA, and serum 8-HdG, and decreased serum GPx and ventilatory functions compared with non-silicotic subgroup.

CONCLUSION

Oxidative stress biomarkers were abnormal with impairment of ventilatory functions among silica-exposed workers.

Real-time measurements of mineral dust concentration in coarse particulate matter (PM10-2.5) by employing a novel optical-based technique in Los Angeles

As a primary component of coarse particulate matter (PM), ambient mineral dust has been linked to adverse health effects. Los Angeles, the largest metropolitan urban area of the United States, is impacted by both windblown and localized sources of mineral dust, often internally mixed with black carbon. The estimation of mineral dust concentrations with a high time resolution becomes critical in improving our understanding of its sources and temporal trends. Using Aethalometers combined with a high-volume virtual impactor (VI) to enrich coarse (2.5 <dp < 10 μm) particles, the light absorption and mass concentration of mineral dust were estimated in real-time during summer, fall, and winter over 2020-2021. The concentration-enriched coarse PM was collected on Teflon filters, and its chemical composition in terms of trace elements and metals was chemically quantified. The high time-resolution measurements enabled us to calculate the absorption coefficient of enriched dust particles by subtracting the light absorption of the post-VI coarse PM from that of the PM_2.5 aerosol fraction to reduce the impact of stronger light absorbers in ambient PM. Mineral dust was more prevalent during the fall and winter campaigns (i.e., 19.3 and 11.4 μg/m³, respectively), lower concentrations were observed during the summer campaign (i.e., 8.50 μg/m³). The calculated absorption Ångström exponent (AAE) was 2.18, highlighting the presence of dust particles during the sampling period. The dust mass absorption coefficient was estimated to be 2.7 ± 1.6 Mm^-1 at 370 nm and 0.41 ± 0.16 Mm^-1 at 880 nm wavelengths, respectively. The validation of the proposed approach was investigated by comparing the evaluated mineral dust mass concentrations in this study with the reported coarse PM concentrations by the California Air Resources Board (CARB). The results reported by the optical-based approach with high temporal resolution can provide crucial information on identifying sources of mineral dust in urban areas.

Pulmonary function parameters among marble industry workers in Lahore, Pakistan

Background: Occupational contact with dust particles is a well-known phenomenon, particularly in developing countries of the world. Crystalline silica present in marble dust is the main etiology of a rising prevalence of obstructive lung diseases in marble stone workers, who are in direct contact with marble dust in the surrounding environment during their regular work.  The purpose of this study was to compare the pulmonary function parameters of workers in marble workshops and age matched healthy individuals in the Lahore District of Pakistan. Methods: The study included 164 male individuals, 82 individuals working in marble workshops and 82 healthy individuals from the same community. Data were collected through in-person interviews using a structured questionnaire after obtaining written consent. A Spiro Lab spirometry for pulmonary function tests was used to identify any change in the lung function parameters. FVC% (forced vital capacity), FEV 1 (forced expiratory volume in first second) and FEV1 / FVC ratio were evaluated. Results: Mean age in the exposed group (marble workers) and non-exposed group (healthy individuals) were 29.92 ± 6.19 and 30.58 ± 6.37 years, respectively. The mean years of work experience of the exposed group was 11.92 ± 5.67 years. A statistically insignificant difference was observed between marble exposed workers & healthy individuals from the demographic variables. Lung function parameters in marble workers exhibited a highly significant (P < 0.001) decrease in FVC%, FEV 1 & FEV 1 / FVC ratio when compared to healthy individuals. Seventy-one percent of marble workers had abnormal pulmonary parameters whereas 34% of workers had restrictive pulmonary impairment. Marble workers who had worked for more than 15 years had a highly significant risk of developing abnormal pulmonary function (P < 0.001). Conclusion: Continuous exposure to marble dust deteriorates the lung function of marble workers.

Respiratory health and silicosis in artisanal mine workers in southern Brazil

BACKGROUND

Artisanal and small-scale mining (ASM) are an important source of employment in southern Brazil. Mining workers are frequently exposed to unhealthy work conditions which increase the risk of occupational diseases. In this study, we assessed the association of sociodemographic factors and the occupational history of artisanal mining workers with the risk of adverse respiratory outcomes.

METHODS

The study was conducted with 258 artisanal mining workers in southern Brazil, who were exposed to dust (mainly crystalline silica) in their work. Information on sociodemographic variables and occupational histories was collected between 2017 and 2018. To estimate the worker's exposure to inhalable dust we use the Advanced REACH (Registration, Evaluation, and Authorization of Chemicals) Tool (ART).

RESULTS

Study participants were all men, with an average age of 40 years. Median crude dust exposure estimated by ART was 13.2 mg/m³ and median crude crystalline silica exposure was 1.6 mg/m³ . The prevalence ratio (PR) for self-reported silicosis was 3.08 (95% confidence interval, 1.39-7.17) in workers with 20 years or more of mining work. Factors associated with silicosis were age, pack-years of tobacco use, and body mass index. Smokers were over twice as likely to report respiratory symptoms.

CONCLUSIONS

Our findings indicate that a high prevalence of silicosis and other associated diseases in mining workers is associated with both unhealthy work environment conditions and the health profile of workers. This study is an important step for understanding health outcomes from work in ASM.

Chronic productive cough and inhalant occupational exposure-a study of the general population

PURPOSE

Occupational inhalant exposures have been linked with a higher occurrence of chronic productive cough, but recent studies question the association.

METHODS

We included participants from two general population studies, the Copenhagen City General Population Study and the Copenhagen City Heart Study, to assess contemporary (year 2003-2017) and historical (1976-1983) occupational inhalant hazards. Job titles one year prior to study inclusion and an airborne chemical job-exposure matrix (ACE JEM) were used to estimate occupational exposure. The association between occupational exposures and self-reported chronic productive cough was studied using generalized estimating equations stratified by smoking status and cohort.

RESULTS

The population consisted of 5210 working individuals aged 20-65 from 1976 to 1983 and 64,279 from 2003 to 2017. In smokers, exposure to high levels of mineral dust, biological dust, gases & fumes and the composite variable vapours, gases, dusts or fumes (VGDF) were associated with chronic productive cough in both cohorts with odds ratios in the range of 1.2 (95% confidence interval, 1.0;1.4) to 1.6 (1.2;2.1). High levels of biological dust were only associated with an increased risk of a chronic productive cough in the 2003-2017 cohort (OR 1.5 (1.1;2.0)). In non-smokers, high levels of VGDF (OR 1.5 (1.0;2.3)) and low levels of mineral dust (OR 1.7 (1.1;2.4)) were associated with chronic productive cough in the 1976-1983 cohort, while no associations were seen in non-smokers in the 2003-2017 cohort.

CONCLUSION

Occupational inhalant exposure remains associated with a modestly increased risk of a chronic productive cough in smokers, despite declining exposure levels during the past four decades.

Investigation of the health effects on workers exposed to respirable crystalline silica during outdoor and underground construction projects

Chronic exposure of workers to powder containing crystalline silica (Silicon dioxide; SiO2) can lead to chronic lung diseases (lung cancer, silicosis, etc.). Aim of this study was to evaluate the exposure of Greek construction workers to SiO2 and describe their pulmonary function. The study involved 86 outdoor and underground workers. Medical and professional history was obtained, and breath samples were collected at morning hours through a mask for the determination of SiO2 levels. Pulmonary function tests, radiological examination and evaluation of radiographs were also performed. Pulmonary function examination showed that the majority of the workers were within normal range (61.4%) while the rest were diagnosed with mild (26.5%) and more severe impairment (7.24%). Working conditions (underground-outdoor) were statistically significantly related to the categorization of pulmonary function (P=0.038). During radiological examination, the type of working activity/ conditions (underground-outdoor) were statistically significantly related to the categorization of these findings (P=0.044). Of the 69 employees, 52 did not present findings (75.4%) and 5 were diagnosed with findings specific to occupational diseases (7.23%). Environmental exposure to respirable crystalline silica (RCS) was detected at 0.0125 mg/m3 in the workplace, which is not beyond the legal limits. Underground workers with more than 15 years of exposure to SiO2 are more likely to present chronic silicosis compared to the workers of outdoor activities.

Respiratory Symptoms and Diminished Lung Functions Associated with Occupational Dust Exposure Among Iron Ore Mine Workers in Iran

Background:

Dust exposure at quarry mines is inevitable and can result in poor air quality. This research aimed to assess pulmonary symptoms and lung functions of dust-exposed workers at an iron-ore mine in eastern Iran.

Methods:

An environmental cross-sectional study sampled 174 dust-exposed mine workers and 93 unexposed administrative employees as the reference group. A standardized questionnaire on respiratory symptoms was completed in accordance with recommendations of the American Thoracic Society(ATS). Calibrated spirometer measured Pulmonary Function Tests (PFTs). Data were analyzed via SPSS-21, integrating independent samples t-test, Chi-square and linear or logistic-regression models.

Results:

There was no significant variation between dust-exposed and reference groups in terms of age, weight, height, work experience and the number of smokers (P>0.05). Mean levels of exposure to inhalable and respirable mineral-dust were 15.09±2.34 and 3.45±2.57 mg/m³ respectively. Pulmonary capacities of dust-exposed group were considerably decreased as compared to others (Forced Vital Capacity [FVC] 86.55±13.77 vs. 105.05±21.5; Forced Expiratory Volume in 1 second [FEV1] 88.06±16.8 vs. 105.81±21.55; FEV1/FVC 103.03±18.17 vs. 93.3±12.49; and Peak Expiratory Flow [PEF] 89.82±22.58 vs. 98.09±20.60) (P<0.001); with a higher prevalence of cough (P=0.041), wheezing (P=0.032), and dyspnea (P=0.035) among formers. Age along with exposure to respirable-dust significantly reduced FVC, FEV1 and FEV1/FVC. Cigarette consumption attenuated FVC and FEV1 on an average of 5 to 9 units.

Conclusion:

Controlled occupational dust-exposure is a definitive pre-requisite to reduce respiratory problems among quarry workers, with an explicit consideration towards mineral- mine workers. Modifiable accomplices like smoking and non-compliance of PPEs usage should be amicably resolved.

Accelerated lung function decline in an aluminium manufacturing industry cohort exposed to PM2.5: an application of the parametric g-formula

OBJECTIVE

Occupational dust exposure has been associated with accelerated lung function decline, which in turn is associated with overall morbidity and mortality. In the current study, we assess potential benefits on lung function of hypothetical interventions that would reduce occupational exposure to fine particulate matter (PM2.5) while adjusting for the healthy worker survivor effect.

METHODS

Analyses were performed in a cohort of 6485 hourly male workers in an aluminium manufacturing company in the USA, followed between 1996 and 2013. We used the parametric g-formula to assess lung function decline over time under hypothetical interventions while also addressing time-varying confounding by underlying health status, using a composite risk score based on health insurance claims.

RESULTS

A counterfactual scenario envisioning a limit on exposure equivalent to the 10th percentile of the observed exposure distribution of 0.05 mg/m3 was associated with an improvement in forced expiratory volume in one second (FEV1) equivalent to 37.6 mL (95% CI 13.6 to 61.6) after 10 years of follow-up when compared with the observed. Assuming a linear decrease and (from NHANES reference values), a 20 mL decrease per year for a 1.8 m-tall man as they age, this 37.6 mL FEV1 loss over 10 years associated with observed exposure would translate to approximately a 19% increase to the already expected loss per year from age alone.

CONCLUSIONS

Our results indicate that occupational PM2.5 exposure in the aluminium industry accelerates lung function decline over age. Reduction in exposure may mitigate accelerated loss of lung function over time in the industry.

Transformation of gaseous 2-bromophenol on clay mineral dust and the potential health effect

Iron-bearing clays are ubiquitously distributed as mineral dusts in the atmosphere. Bromophenols were reported as the major products from thermal decomposition of the widely used brominated flame retardants (BFRs). However, little information is available for the reactivity of iron associated with mineral dusts to interact with the atmospheric bromophenols and the subsequent toxic effects. Herein, three common clay minerals (montmorillonite, illite and kaolinite) were used to simulate mineral dusts, and the reactions with gaseous 2-bromophenol were systematically investigated under environmentally relevant atmospheric conditions. Our results demonstrate that structural Fe(III) in montmorillonite and Fe(III) from iron oxide in illite mediated the dimerization of 2-bromophenol to form hydroxylated polybrominated biphenyl and hydroxylated polybrominated diphenyl ether. The surface reaction is favored to occur at moisture environment, since water molecules formed complex with 2-bromophenol and the reaction intermediates via hydrogen bond to significantly lower the reaction energy and promote the dimerization reaction. More importantly, the formed dioxin-like products on clay mineral dust increased the toxicity of the particles to A549 lung cell by decreasing cell survival and damaging cellular membrane and proteins. The results of this study indicate that not only mineral dust itself but also the associated surface reaction should be fully considered to accurately evaluate the toxic effect of mineral dust on human health.

Breast-Feeding Protects Children from Adverse Effects of Environmental Tobacco Smoke

In a cross-sectional study on 433 schoolchildren (aged 6⁻9 years) from 9 schools in Austria, we observed associations between housing factors like passive smoking and lung function as well as improved lung function in children who had been breast-fed. The latter findings urged the question of whether the protective effects of breast-feeding act on environmental stressors or if they act independently. Therefore, the effect of passive smoking on lung function was stratified by breast-feeding. The detrimental effects of passive smoking were significant but restricted to the group of 53 children without breast-feeding. Breast-feeding counteracts the effect of environmental stressors on the growing respiratory organs.

Laboratory evaluation of a low-cost, real-time, aerosol multi-sensor

Exposure to occupational aerosols are a known hazard in many industry sectors and can be a risk factor for several respiratory diseases. In this study, a laboratory evaluation of low-cost aerosol sensors, the Dylos DC1700 and a modified Dylos known as the Utah Modified Dylos Sensor (UMDS), was performed to assess the sensors' efficiency in sampling respirable and inhalable dust at high concentrations, which are most common in occupational settings. Dust concentrations were measured in a low-speed wind tunnel with 3 UMDSs, collocated with an aerosol spectrometer (Grimm 1.109) and gravimetric respirable and inhalable samplers. A total of 10 tests consisting of 5 different concentrations and 2 test aerosols, Arizona road dust and aluminum oxide, were conducted. For the Arizona road dust, total particle count was strongly related between the spectrometer and the UMDS with a coefficient of determination (R2) between 0.86-0.92. Particle count concentrations measured with the UMDS were converted to mass and also were related with gravimetrically collected inhalable and respirable dust. The UMDS small bin (i.e., all particles) compared to the inhalable sampler yielded an R2 of 0.86-0.92, and the large bin subtracted from the small bin (i.e., only the smallest particles) compared to the respirable sampler yielded an R2 of 0.93-0.997. Tests with the aluminum oxide demonstrated a substantially lower relationship across all comparisons. Furthermore, assessment of intra-instrument variability was consistent for all instruments, but inter-instrument variability indicated that each instrument requires its own calibration equation to yield accurate exposure estimates. Overall, it appears that the UMDS can be used as a low-cost tool to estimate respirable and inhalable concentrations found in many workplaces. Future studies will focus on deployment of a UMDS network in an occupational setting.

Cigarettes, Smokeless Tobacco, and Poly-Tobacco Among Workers in Three Dusty Industries

BACKGROUND

Tobacco use remains high among blue-collar workers, the health consequences of which may be compounded by occupational dust exposure. Detailed data on tobacco use among workers in dusty industries are lacking.

METHODS

The 2006 to 2012 National Survey on Drug Use and Health was used to compare current tobacco use prevalence [including cigarettes, smokeless tobacco (SLT), and both (dual use)] among male workers in three dusty industries to all other employed men using bivariate and multivariate analysis.

RESULTS

Smoking rates were high among extraction (39.9%) and construction (38.5%) workers. Increased odds of SLT (odds ratio = 3.3) and dual use (odds ratio = 2.6) were observed among dusty-industry workers compared with other employed men. The prevalence of any tobacco use was unexpectedly high among extraction workers (60.4%).

CONCLUSIONS

Disparities in tobacco use behaviors by industry may point to opportunities for targeted workplace tobacco cessation programs.

Peak exposures to main components of ash and gaseous diesel exhausts in closed and open ash loading stations at biomass-fuelled power plants

Fly and bottom ashes are collected at power plants to reduce the environmental effects of energy production. However, handling the ashes causes health problems for operators, maintenance workers and truck drivers at the power plants. Hence, we evaluated ash loaders' peak inhalation exposures to the chemical components of ash and diesel exhausts in open and closed ash loading stations at biomass-fuelled combined heat and power plants. We also carried out chemical and morphological analyses of the ashes to evaluate their health hazard potential in order to find practical technical measures to reduce workers' exposure. On the basis of X-ray diffraction analyses, the main respirable crystalline ash compounds were SiO₂, CaSO₄, CaO, Ca₂Al₂SiO₇, NaCl and Ca₃Al₂O₆ in the fly ashes and SiO₂, KAlSi₃O₈, NaAlSi₃O₈ and Ca₂Al₂SiO₇ in the bottom ashes. The short-term exposure levels of respirable crystalline silica, inhalable inorganic dust, Cr, Mn, Ni and nitric oxide exceeded their Finnish eight hours occupational exposure limit values in the closed ash loading station. According to our observations, more attention should be paid to the ash-moistening process, the use of tank trucks instead of open cassette flatbed trucks, and the sealing of the loading line from the silo to the truck which would prevent spreading the ash into the air. The idling time of diesel trucks should also be limited, and ash loading stations should be equipped with exhaust gas ventilators. If working conditions make it impossible to keep to the OEL values, workers must use respirators and protect their eyes and skin.

High Cigarette and Poly-Tobacco Use Among Workers in a Dusty Industry: New Jersey Quarry Workers

OBJECTIVE

Tobacco use is high among US extraction and construction workers, who can also incur occupational dust exposure. Information on different types of tobacco use among quarry/mine workers is sparse.

METHODS

During mandated training sessions, New Jersey quarry workers were surveyed about their tobacco use. Prevalence was calculated for single and multiple tobacco use by demographic and workplace characteristics; logistic regression was used to assess associations with smoking.

RESULTS

Two hundred forty (97.1%) workers completed surveys. Among respondents, 41.7% [95% confidence interval (95% CI) 35.4 to 48.3] currently used any tobacco product of whom 28.1% smoked cigarettes. In multivariate analysis, positive associations with smoking included working as a contractor versus mine employee (odds ratio 2.32, 95% CI 1.01 to 5.36) and a usual job title of maintenance (odds ratio 2.02, 95% CI 0.87 to 4.94).

CONCLUSION

Industry-specific information may be helpful in developing targeted tobacco-cessation programs.

Dust and Cobalt Levels in the Austrian Tungsten Industry: Workplace and Human Biomonitoring Data

In general, routine industrial hygiene (IH) data are collected not to serve for scientific research but to check for compliance with occupational limit values. In the preparation of an occupational retrospective cohort study it is vital to test the validity of the exposure assessment based on incomplete (temporal coverage, departments) IH data. Existing IH data from a large hard metal plant was collected. Individual workers’ exposure per year and department was estimated based on linear regression of log-transformed exposure data for dust, tungsten, and cobalt. Estimated data were back-transformed, and for cobalt the validity of the estimates was confirmed by comparison with individual cobalt concentrations in urine. Air monitoring data were available from 1985 to 2012 and urine tests from the years 2008 to 2014. A declining trend and significant differences among departments was evident for all three air pollutants. The estimated time trend fitted the time trend in urine values well. At 1 mg/m³, cobalt in the air leads to an excretion of approximately 200 µg/L cobalt in urine. Cobalt levels in urine were significantly higher in smokers with an interaction effect between smoking and air concentrations. Exposure estimates of individual workers are generally feasible in the examined plant, although some departments are not documented sufficiently enough. Additional information (expert knowledge) is needed to fill these gaps.

Drillers and mill operators in an open-pit gold mine are at risk for impaired lung function

BACKGROUND

Occupational studies of associations of exposures with impaired lung function in mining settings are built on exposure assessment and far less often on workplace approach, so the aim of this study was to identify vulnerable occupational groups for early lung function reduction in a cohort of healthy young miners.

METHODS

Data from annual screening lung function tests in gold mining company in Kyrgyzstan were linked to occupations. We compared per cent predicted forced expiratory volume in one second (FEV1), forced vital capacity (FVC) and FEV1/FVC between occupational groups and tested selected occupations in multivariate regression adjusted for smoking and work duration for the following outcomes: FEV1 < 80 %, FEV1/FVC < 70 % and both.

RESULTS

1550 tests of permanent workers of 41 occupations (mean age 40.5 ± 9.2 years, 29.8 % never smokers) were included in the analysis. The mean overall VC was 103.0 ± 12.9 %; FVC 109.1 ± 13.0 % and FEV1 100.2 ± 25.9 %. Drillers and smoking food handlers had the lowest FEV1%. In non-smokers, the lowest FEV1 was in drillers (94.9 ± 11.3 % compared to 115.2 ± 17.7 % in engineers). Drillers (adjusted odds ratio (OR) 1.53 (95 % confidence interval (CI) 1.11-2.09)) and mill operators (OR 2.01 (1.13-3.57)) were at greater risk of obstructive ventilation pattern (FEV1/FVC < 70 %).

CONCLUSIONS

Drilling and mill operations are the highest risk jobs in an open-pit mine for reduced lung function. Occupational medical clinic at site should follow-up workers in these occupations with depth and strongly recommend smoking cessation.

Diminished pulmonary function in long-term workers exposed to cotton dust determined in a cross-sectional study in small Pakistani enterprises

PURPOSE

While large cotton industry plants producing for the foreign market have undergone improvements of occupational hygiene lately, working conditions in power looms producing mainly for the local market are still poor. The respiratory health in workers of power looms has not been studied so far.

METHODS

In a cross-sectional study, 51 male cotton workers from power looms, 58 from large cotton factories and 52 controls were investigated by spirometry and a symptoms questionnaire. Spirometric measurements and respiratory symptoms were related to exposure duration in large and small factories by multivariate linear regression and logistic regression, respectively, with smoking, age and anthropometric parameters considered as confounders.

RESULTS

Work duration in power looms was associated with declines in forced expiratory volume in 1 s, peak flow, maximum midexpiratory flow and forced expiratory flow 75 and an increased risk of obstruction (OR 1.09/year; 95% CI: 1.002 to 1.18) by applying the Global Lung Initiative equations. Except cough that was only associated with smoking, all respiratory symptoms (chest tightness, shortness of breath, fever) increased as a function of duration of exposure in power looms but not in large factories.

CONCLUSIONS

Despite limitations inherent in the cross-sectional approach, there is evidence for workers in small weaving factories to face an increased risk of pulmonary function loss and respiratory symptoms. Industrial hygiene measures in these small enterprises should be encouraged. Failure to detect adverse respiratory outcomes from occupation in large factories could be due to a 'survivor' (healthy worker) effect.

Guidelines for the diagnosis and monitoring of silicosis

Silicosis is one of the occupational respiratory diseases most commonly encountered in our setting. It is caused by inhalation of crystalline silica that triggers a fibrotic response in the lung parenchyma. It presents as diffuse interstitial disease and clinical expression ranges from asymptomatic forms to chronic respiratory failure. Diagnosis is based on clinical history and radiological findings. There is no effective treatment, and once diagnosed, the patient must avoid all sources of occupational exposure. In these guidelines, the clinical, radiological and functional aspects of silicosis are reviewed, and strategies for diagnosis, monitoring and classification of patients are proposed, along with recommendations regarding the occupational implications of this disease.

The impact of reduced dust exposure on respiratory health among cement workers: an ecological study

OBJECTIVES

To compare total dust exposure, prevalence of chronic respiratory symptoms, lung function, and chronic obstructive pulmonary disease (COPD) among Tanzanian cement workers before (2002) and after (2010-2011) establishment of dust-control measures.

METHODS

Personal total dust-exposure measurements, questionnaire assessment for chronic respiratory symptoms, and spirometry were conducted in both examination periods.

RESULTS

Total dust exposure was lower in 2010-2011 than in 2002. The prevalence of most chronic respiratory symptoms and COPD was lower in 2010 than in 2002. Forced expiratory volume in 1 second (FEV1), percentage predicted FEV1, and percentage predicted forced vital capacity were higher among cement workers in 2010 than in 2002.

CONCLUSIONS

There was reduced total dust exposure level, lower prevalence of chronic respiratory symptoms and COPD, and higher lung function among cement workers in 2010 than in 2002.