Ultrafine particles and black carbon personal exposures in asthmatic and non-asthmatic children at school age.

Traffic-related air pollution (TRAP) exposure during childhood is associated with asthma; however, the contribution of the different TRAP pollutants in each microenvironment (home, school, transportation, others) in asthmatic and non-asthmatic children is unknown. Daily (24-h) personal black carbon (BC), ultrafine particle (UFP), and alveolar lung-deposited surface area (LDSA) individual exposure measurements were obtained from 100 children (29 past and 21 current asthmatics, 50 non-asthmatics) aged 9±0.7 years from the INMA-Sabadell cohort (Catalonia, Spain). Time spent in each microenvironment was derived by the geolocation provided by the smartphone and a new spatiotemporal map-matching algorithm. Asthmatics and non-asthmatics spent the same amount of time at home (60% and 61%, respectively), at school (20% and 23%), on transportation (8% and 7%), and in other microenvironments (7% and 5%). The highest concentrations of all TRAPs were attributed to transportation. No differences in TRAP concentrations were found overall or by type of microenvironment between asthmatics and non-asthmatics, nor when considering past and current asthmatics, separately. In conclusion, asthmatic and non-asthmatic children had a similar time-activity pattern and similar average exposures to BC, UFP, and LDSA concentrations. This suggests that interventions should be tailored to general population, rather than to subgroups defined by disease.

Patterns of domestic exposure to carbon monoxide and particulate matter in households using biomass fuel in Janakpur, Nepal.

Household Air Pollution (HAP) from biomass cooking fuels is a major cause of morbidity and mortality in low-income settings worldwide. In Nepal the use of open stoves with solid biomass fuels is the primary method of domestic cooking. To assess patterns of domestic air pollution we performed continuous measurement of carbon monoxide (CO) and particulate Matter (PM2.5) in 12 biomass fuel households in Janakpur, Nepal. We measured kitchen PM2.5 and CO concentrations at one-minute intervals for an approximately 48-h period using the TSI DustTrak II 8530/SidePak AM510 (TSI Inc, St. Paul MN, USA) or EL-USB-CO data logger (Lascar Electronics, Erie PA, USA) respectively. We also obtained information regarding fuel, stove and kitchen characteristics and cooking activity patterns. Household cooking was performed in two daily sessions (median total duration 4 h) with diurnal variability in pollutant concentrations reflecting morning and evening cooking sessions and peak concentrations associated with fire-lighting. We observed a strong linear relationship between PM2.5 measurements obtained by co-located photometric and gravimetric monitoring devices, providing local calibration factors of 4.9 (DustTrak) and 2.7 (SidePak). Overall 48-h average CO and PM2.5 concentrations were 5.4 (SD 4.3) ppm (12 households) and 417.6 (SD 686.4) µg/m3 (8 households), respectively, with higher average concentrations associated with cooking and heating activities. Overall average PM2.5 concentrations and peak 1-h CO concentrations exceeded WHO Indoor Air Quality Guidelines. Average hourly PM2.5 and CO concentrations were moderately correlated (r = 0.52), suggesting that CO has limited utility as a proxy measure for PM2.5 exposure assessment in this setting. Domestic indoor air quality levels associated with biomass fuel combustion in this region exceed WHO Indoor Air Quality standards and are in the hazardous range for human health.

The exposome in practice: Design of the EXPOsOMICS project.

EXPOsOMICS is a European Union funded project that aims to develop a novel approach to the assessment of exposure to high priority environmental pollutants, by characterizing the external and the internal components of the exposome. It focuses on air and water contaminants during critical periods of life. To this end, the project centres on 1) exposure assessment at the personal and population levels within existing European short and long-term population studies, exploiting available tools and methods which have been developed for personal exposure monitoring (PEM); and 2) multiple "omic" technologies for the analysis of biological samples (internal markers of external exposures). The search for the relationships between external exposures and global profiles of molecular features in the same individuals constitutes a novel advancement towards the development of "next generation exposure assessment" for environmental chemicals and their mixtures. The linkage with disease risks opens the way to what are defined here as 'exposome-wide association studies' (EWAS).

Traffic pollution and the incidence of cardiorespiratory outcomes in an adult cohort in London.

OBJECTIVES: The epidemiological evidence for adverse health effects of long-term exposure to air and noise pollution from traffic is not coherent. Further, the relative roles of background versus near traffic pollution concentrations in this process are unclear. We investigated relationships between modelled concentrations of air and noise pollution from traffic and incident cardiorespiratory disease in London. METHODS: Among 211 016 adults aged 40-79 years registered in 75 Greater London practices between 2005 and 2011, the first diagnosis for a range of cardiovascular and respiratory outcomes were identified from primary care and hospital records. Annual baseline concentrations for nitrogen oxide (NOx), particulate matter with a median aerodynamic diameter <2.5 µm (PM2.5) attributable to exhaust and non-exhaust sources, traffic intensity and noise were estimated at 20 m2 resolution from dispersion models, linked to clinical data via residential postcode. HRs were adjusted for confounders including smoking and area deprivation. RESULTS: The largest observed associations were between traffic-related air pollution and heart failure (HR=1.10 for 20 µg/m3 change in NOx, 95% CI 1.01 to 1.21). However, no other outcomes were consistently associated with any of the pollution indicators, including noise. The greater variations in modelled air pollution from traffic between practices, versus within, hampered meaningful fine spatial scale analyses. CONCLUSIONS: The associations observed with heart failure may suggest exacerbatory effects rather than underlying chronic disease. However, the overall failure to observe wider associations with traffic pollution may reflect that exposure estimates based on residence inadequately represent the relevant pattern of personal exposure, and future studies must address this issue.

International scale implementation of the CNOSSOS-EU road traffic noise prediction model for epidemiological studies.

The EU-FP7-funded BioSHaRE project is using individual-level data pooled from several national cohort studies in Europe to investigate the relationship of road traffic noise and health. The detailed input data (land cover and traffic characteristics) required for noise exposure modelling are not always available over whole countries while data that are comparable in spatial resolution between different countries is needed for harmonised exposure assessment. Here, we assess the feasibility using the CNOSSOS-EU road traffic noise prediction model with coarser input data in terms of model performance. Starting with a model using the highest resolution datasets, we progressively introduced lower resolution data over five further model runs and compared noise level estimates to measurements. We conclude that a low resolution noise model should provide adequate performance for exposure ranking (Spearman's rank = 0.75; p < 0.001), but with relatively large errors in predicted noise levels (RMSE = 4.46 dB(A)).

Effect of water velocity on hydroponic phytoremediation of metals.

The influence of flow velocity on the uptake of cadmium, copper, lead, and zinc by hydroponically grown soft stem bulrush (Scirpus validus) was investigated. The roots of the plants were exposed to a continually recycled, nutrient enriched, synthetic stormwater. Plants were divided into groups and the roots of each group exposed to different but constant water velocities. The metal concentrations in the roots and stems were compared after three weeks. Metal accumulation in roots was increased for water velocities between 1.3 and 4.0 cm s(-1). In a second experiment, the roots of all plants were exposed to a single velocity and the root and stem metal concentrations were determined as a function of time. Metal concentrations in the roots approached a constant value after three weeks. After this time, accumulation of metals depends upon root growth. The results suggest that long-term accumulation by the roots of hydroponic Scirpus validus can be increased by increasing water velocity, which implies that floating islands with movement will retain more metals from the water column.

Time activity modelling of domestic exposures to radon.

Radon gas occurs naturally in the environment with a variable distribution. In some areas radon concentrates sufficiently within the built environment that it is considered as a public health risk. It is possible, successfully, to reduce radon levels in the built environment, and it has been shown that such remediation programmes can be justified in terms of the costs and benefits accruing. However, the estimated dose received by people in their homes depends on the time spent indoors. The research presented here uses data derived from time activity surveys in Northamptonshire, together with radon data from a representative home, to model potential exposures for different population sub-groups. Average home occupancy ranged from 14.8h (probable error 2.5h) for students to 17.7 (3.1) h for adults; schoolchildren spent an average of 14.9 (1.2) h at home. Over a quarter of adults, however, were in the home for 22 h on more. These differences in occupancy patterns lead to substantial differences in radon exposure. In a home with an average hourly ground floor radon concentration of 467 Bqm(-3), modelled hourly average exposures ranged from ca. 250 Bqm(-3) for students and school children, to over 340 Bqm(-3), for women based at home. Modelled exposures show a non-linear association with total time spent at home, suggesting that exposure estimates based on linear models may provide misleading estimates of health risks from radon and the potential benefits of radon remediation. Highest hourly exposures are likely to be experienced by people with highly occupancy, living in single-storey, ground floor accommodation (for example, the elderly the infirm and non-working young mothers). Since these may be least aware of radon risks, and least able to take up remediation measures, they should be specifically targeted for radon monitoring and for assistance in remediation schemes.

A regression-based method for mapping traffic-related air pollution: application and testing in four contrasting urban environments.

Accurate, high-resolution maps of traffic-related air pollution are needed both as a basis for assessing exposures as part of epidemiological studies, and to inform urban air-quality policy and traffic management. This paper assesses the use of a GIS-based, regression mapping technique to model spatial patterns of traffic-related air pollution. The model--developed using data from 80 passive sampler sites in Huddersfield, as part of the SAVIAH (Small Area Variations in Air Quality and Health) project--uses data on traffic flows and land cover in the 300-m buffer zone around each site, and altitude of the site, as predictors of NO2 concentrations. It was tested here by application in four urban areas in the UK: Huddersfield (for the year following that used for initial model development), Sheffield, Northampton, and part of London. In each case, a GIS was built in ArcInfo, integrating relevant data on road traffic, urban land use and topography. Monitoring of NO2 was undertaken using replicate passive samplers (in London, data were obtained from surveys carried out as part of the London network). In Huddersfield, Sheffield and Northampton, the model was first calibrated by comparing modelled results with monitored NO2 concentrations at 10 randomly selected sites; the calibrated model was then validated against data from a further 10-28 sites. In London, where data for only 11 sites were available, validation was not undertaken. Results showed that the model performed well in all cases. After local calibration, the model gave estimates of mean annual NO2 concentrations within a factor of 1.5 of the actual mean (approx. 70-90%) of the time and within a factor of 2 between 70 and 100% of the time. r2 values between modelled and observed concentrations are in the range of 0.58-0.76. These results are comparable to those achieved by more sophisticated dispersion models. The model also has several advantages over dispersion modelling. It is able, for example, to provide high-resolution maps across a whole urban area without the need to interpolate between receptor points. It also offers substantially reduced costs and processing times compared to formal dispersion modelling. It is concluded that the model might thus be used as a means of mapping long-term air pollution concentrations either in support of local authority air-quality management strategies, or in epidemiological studies.

An aqueous concentration model for riverine spills.

A numerical model is developed to predict the aqueous concentrations of sparingly soluble compounds resulting from oil, fuel, or chemical spills onto rivers. The model computes the concentration of compounds both in the slick phase and in the aqueous phase by simulating the processes that affect the fate of the spilled compound. Processes simulated by the model include spreading and drifting of the surface slick, evaporation from the slick, dissolution from the slick into the water, volatilization from the water, and longitudinal dispersion in the river. The model is used to simulate a hypothetical spill of jet fuel, demonstrating that the concentration of a compound in the aqueous phase is strongly linked to its concentration in the slick phase. The most soluble and most volatile compounds exhibit the highest aqueous concentrations in the early stages of the spill, but ultimately the less soluble and less volatile compounds reach the highest aqueous concentrations. Streamwise concentration gradients in the slick due to the rapid evaporation of the more volatile compounds are shown to have an effect on the aqueous concentration.

Processes controlling aqueous concentrations for riverine spills.

The aqueous concentrations of sparingly soluble compounds resulting from oil, fuel, or chemical spills onto rivers predicted by numerical spill models contain an inherent degree of uncertainty due to the inaccuracies, or bias, of the user supplied rate coefficients. Methods for estimating the values of spreading, evaporation, dissolution, volatilization, and longitudinal dispersion coefficients for a small sheltered river are reviewed, and the uncertainties associated with each coefficient are estimated. The uncertainties in the predicted aqueous concentrations are then computed using a concurrently developed riverine spill model for a simulated spill of 10,000 kg of jet fuel. The resulting aqueous concentrations were found to be most sensitive to the saturation concentrations and the dissolution rates, moderately sensitive to the evaporation rates and longitudinal dispersion coefficient, and nearly completely insensitive to the volatilization coefficient.

Auditory temporal resolution in multiple sclerosis.

Disturbances of hearing in multiple sclerosis patients have been variably reported, likely because standard audiologic testing emphasizes assessment of peripheral, rather than central, auditory function. This study investigated a group of patients with multiple sclerosis (MS), prospectively selected on the basis of magnetic resonance imaging (MRI) scans. Five of these patients had demyelinating lesions that included the rostral auditory fibre tracts, while another seven patients had lesions restricted to brainstem auditory sites. A further four had no lesions in the distribution of their auditory pathways. A comprehensive battery of audiometric tests, including standard audiometry and retrocochlear testing, was performed. In addition, their findings on electrophysiologic testing, including auditory brainstem responses (ABR) and middle latency responses (MLR), were studied. Finally, their performances in gap detection and speech recognition in continuous and interrupted background noise were examined to assess their auditory temporal resolution. The MS patients were found to be selectively impaired under the interrupted masker of this speech-in-noise paradigm, confirming a temporal processing defect. Furthermore, these patients' performances suggested a predominant role of forebrain pathways in mediating auditory temporal resolution.

Impaired word recognition in noise by patients with noise-induced cochlear hearing loss: contribution of temporal resolution defect.

Fifteen patients with mild noise-induced cochlear hearing loss reported a selective difficulty in understanding speech in noisy settings. To examine the hypothesis that a temporal resolution defect was responsible for this difficulty, the patients were tested for their recognition of monosyllabic words presented against continuous and interrupted wide-band noise backgrounds, at each of seven signal-to-noise ratios. Their recognition performance was compared with that of normal listeners studied with the same paradigms. By comparison with the controls, the group with cochlear hearing loss showed a significant recognition impairment only for words presented against the interrupted masker. This finding was in keeping with the existence of a temporal resolution defect in cochlear disease, though it need not indicate a stimulus timing defect at the level of individual cochlear neurons.

Disturbed speech intelligibility in noise despite a normal audiogram: a defect in temporal resolution?

Patients with complaints of disturbed speech intelligibility in noise, despite normal standard audiograms, constitute a unique yet not uncommon population of listeners. The literature on this patient group is reviewed, and the term Idiopathic Discriminatory Dysfunction (IDD) is introduced in an attempt to standardize and qualify the distinct characteristics of this entity. Preliminary studies of these patients have hypothesized both frequency and temporal resolution deficits underlying this impairment. A representative group of 15 patients suffering from IDD were tested using a new speech-in-noise paradigm designed to test temporal resolution. These patients were found to have near-normal temporal resolving capacity as determined by this task.

A fatal copper sulfate poisoning.

An 11-year-old female died within hours of accidentally ingesting a solution of copper sulfate. A postmortem blood sample was found to contain 66 micrograms/mL copper. The initial qualitative identification of this poison in the body organs and fluids was by means of SEM-microprobe analysis (SEM-MPA) and X-ray fluorescence (XRF). The samples were quantified by atomic absorption spectrometry.