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Background: Comprehensive global data on the health effects of indoor air pollutants are lacking. There are few large population-based multi-air pollutant health assessments. Further, little is known about indoor air health risks in the Middle East, especially in countries undergoing rapid economic development., Objectives: To provide multifactorial indoor air exposure and health data, we conducted a population-based study of indoor air pollution and health in the United Arab Emirates (UAE)., Methods: We conducted a cross-sectional study in a population-based sample of 628 households in the UAE. Indoor air pollutants [sulfur dioxide (SO2), nitrogen dioxide (NO2), hydrogen sulfide (H2S), formaldehyde (HCHO), carbon monoxide (CO), and particulate matter] were measured using passive samplers over a 7-day period. Health information was collected from 1,590 household members via in-person interviews., Results: Participants in households with quantified SO2, NO2, and H2S (i.e., with measured concentrations above the limit of quantification) were twice as likely to report doctor-diagnosed asthma. Participants in homes with quantified SO2 were more likely to report wheezing symptoms {ever wheezing, prevalence odds ratio [POR] 1.79 [95% confidence interval (CI) 1.05, 3.05]; speech-limiting wheeze, POR 3.53 (95% CI: 1.06, 11.74)}. NO2 and H2S were similarly associated with wheezing symptoms. Quantified HCHO was associated with neurologic symptoms (difficulty concentrating POR 1.47; 95% CI: 1.02, 2.13). Burning incense daily was associated with increased headaches (POR 1.87; 95% CI: 1.09, 3.21), difficulty concentrating (POR 3.08; 95% CI: 1.70, 5.58), and forgetfulness (POR 2.68: 95% CI: 1.47, 4.89)., Conclusions: This study provides new information regarding potential health risks from pollutants commonly found in indoor environments in the UAE and other countries. Multipollutant exposure and health assessments in cohort studies are needed to better characterize health effects of indoor air pollutants.

Background: The Arabian Gulf nations are undergoing rapid economic development, leading to major shifts in both the traditional lifestyle and the environment. Although the pace of change is brisk, there is a dearth of environmental health research in this region., Objective: We describe challenges and successes of conducting an environmental epidemiologic study in the United Arab Emirates (UAE), a Gulf nation in the Middle East, with an inter-disciplinary team that includes in-country academic and government collaborators as well as U.S. academic collaborators., Discussion: We present several issues, including study and data collection design, exposure assessment, scheduling and time coordination, quality assurance and quality control, and institutional review board protocols. These topics are considered in a cultural context. Benefits of this research included building linkages among multinational, interdisciplinary team members, generating data for local environmental decision making, and developing local epidemiologic research capacity. The Middle Eastern culture of hospitality greatly benefited the project team., Conclusion: Cultural differences impact multiple aspects of epidemiologic research and should be respectfully addressed. Conducting international population-based environmental research poses many challenges; these challenges can be met successfully with careful planning, cultural knowledge, and flexibility. Lessons learned are applicable to interdisciplinary research all over the world. The research conducted will benefit the environmental and public health agencies of the UAE and provide the nation's leadership with country-specific environmental health data that can be used to protect the public's health in a rapidly changing environment.

This study investigates the use of a small passive sampler for aerosol particles to determine particulate matter (PM)10-2.5 concentrations in outdoor air. The passive sampler collects particles by gravity, diffusion, and convective diffusion onto a glass coverslip that is then examined with an optical microscope; digital images are processed with free software and the resultant PM10-2.5 concentrations determined. Both the samplers and the analyses are relatively inexpensive. Passive samplers were collocated with Federal Reference Method (FRM) samplers in Chapel Hill, NC; Phoenix, AZ; and Birmingham, AL; for periods from 5 to 15 days. Particles consisted primarily of inorganic dusts at some sites and a mix of industrial and inorganic materials at other sites. Measured concentrations ranged from < 10 microg/m3 to approximately 40 microg/m3. Overall, PM10-2.5 concentrations measured with the passive samplers were within approximately 1 standard deviation of concentrations measured with the FRM samplers. Concentrations determined with passive samplers depend on assumptions about particle density and shape factors and may also depend somewhat on local wind speed and turbulence; accurate values for these parameters may not be known. The degree of agreement between passive and FRM concentrations measured here suggests that passive measurements may not be overly dependent on accurate knowledge of these parameters.

Effective mist collection is important, but it is not the only determinant of mist concentration in plant air. Oil-based metalworking fluids such as straight and soluble oils contain semivolatile hydrocarbons. When these fluids form a mist, their semivolatile components partition between the vapor and mist phases depending on the makeup of the mist and on local conditions. This article addresses the relationship between the concentrations of semivolatile hydrocarbons in the vapor and mist phases using theory for partitioning developed in the field of atmospheric chemistry. Mist can be removed effectively in a collector that uses a HEPA filter as its final collection stage. Acceptable HEPA lifetime requires effective upstream stages that reduce mist loading to the HEPA; furthermore, acceptable HEPA performance requires that it be installed and maintained properly. Collectors designed to remove mist do not remove vapor, and as collector exhaust mixes into cooler plant air that already contains some mist, vapor from the collector can repartition to increase the mist concentration in the plant. Assessing the effect of vapor-to-mist repartitioning is complicated; however, repartitioning may be important for many of the compounds contained in oil-based metalworking fluids. Conditions that minimize vapor-to-mist repartitioning, such as ventilating the plant with clean outdoor air, increasing plant temperature, or controlling the release of vapor, may also be expensive, uncomfortable to plant occupants, or impractical from an engineering standpoint. As a result, very low mist concentrations in plant air may be difficult to attain.

This study investigated the potential for mineral oil mist to evaporate, during sampling, from filters and electrostatic precipitator substrates used to assess personal exposure. If sample evaporation occurs, reported mist concentrations will underestimate true exposure. Mineral oil used as a machining fluid is not normally considered volatile; however, when dispersed as mist its aggregate surface area is so high that significant evaporation can occur. National Institute for Occupational Safety and Health Method 5026 specifies that oil mist concentrations should be determined by collecting mist on filters of mixed cellulose esters (MCE) or polyvinyl chloride (PVC). Collected mist droplets remain dispersed on the filter surface and in contact with passing air while sampling continues, conditions that can lead to sample evaporation. Less evaporation should occur for samples taken with an electrostatic precipitator, where mist droplets are separated from the airflow by electrostatic force and coalesce on the precipitator wall to form a film with relatively low surface area. Collection of mineral oil mist was investigated using a precipitator designed for personal sampling and using either an MCE or a PVC filter. The amounts of oil mist collected using the precipitator were significantly higher than the amounts collected using the filters, p < 0.001. Further tests in which clean air passed through mist-loaded precipitators and filters showed that the precipitator retained substantially more collected mist than both filters, p < 0.001, and further suggested that the MCE filter retained more mist than the PVC filter, p = 0.059. Differences in sample collection and retention between the precipitator and the filters were particularly pronounced at mist loadings below 1 mg.

A method is presented to examine factors that affect the amount and size distribution of dust generated by falling granular material in still air. This work was conducted by using an apparatus with separate dust generating and dust measuring sections. The dust generated by a falling material was carried into an elutriation column equipped with a slotted Sierra high-volume impactor at the top. This apparatus can measure dust generation rates for particles between 0.4 and 25 microns in aerodynamic diameter as well as the amount of air entrained by the falling material. Four granular materials were tested, and a simple model was developed to describe the dust generation rate of these materials as a function of particle size, drop height, material flow, and moisture content. Moisture content strongly influenced the interparticle binding forces and the amount of dust generated. Drop height and material flow influenced the material separation forces and also significantly influenced the amount of dust generated.

Miners and millers of talc ore, free from asbestos and silica, were examined for respiratory effects. A study of 116 subjects included the modified British Medical Research Council respiratory symptom questionnaire, simple spirometry, chest radiography, and limited examination of the chest. A one-year follow-up evaluation was performed on 103 subjects. Of the 12 subjects whose chest radiographs showed small round or irregular opacities (perfusion 1/0 or greater), five had never smoked cigarettes. Pulmonary function values at the time of the initial study were less than predicted and the rates of loss of FEV1 and FVC greater than expected. These differences were in part attributed to cigarette smoking but were greater than predicted from that source alone. There was evidence of an exposure effect after adjusting for cigarette smoking and we conclude that these workers have been affected by their exposures. No clear interaction between smoking and exposure could be identified. Populations such as this will need to be studied for longer periods to determine what current dust levels are safe.