Variability of Personal Exposure to Fine Particulates for Urban Commuters inside an Automobile

Over the last decade, a growing body of evidence has emerged to suggest a causal link between short-duration exposure to elevated levels of fine airborne particulate matter and adverse health consequences. It is believed much of this ‘peak’ exposure occurs in transport microenvironments both because of the higher levels of fine particulates associated with road traffic, primarily from diesel exhaust emissions, and the fact people spend a significant amount of time traveling (for instance, 80 minutes/day for residents of Sydney). While previous studies have suggested substantial differences in exposure rates due to factors such as choice of mode, route, in-vehicle conditions, and meteorological factors, current measurement techniques have restricted insights to fairly coarse sampling intervals (e.g., every half hour, every trip). As a consequence, little tangible evidence is available on how pollution varies over a trip and most critically about the location, duration, and magnitude of peak excursions within trips. The current paper reports on a study in which the capabilities of Global Positioning Systems (GPS) and real-time particle monitors are combined to address this problem for an urban commute trip in Sydney. This ability to precisely spatially reference pollution data and in particular identify ‘hotspots’ holds considerable promise for both our understanding and reporting of such data in the future

Sample Size Requirements For Measuring a Change in Behaviour

Before and after surveys are designed to detect a change in travel-behaviour following an intervention policy, such as a travel-modification program. Longitudinal panel surveys are the preferred method for detecting such changes, because the variance of the difference between the before and after surveys is substantially reduced, enabling changes to be detected with smaller sample sizes than if a repeated crosssectional survey is used. A key issue concerns the size of sample required to be able to generalise the Panel results to the population; that is to state, with 95% confidence that if there is a ?% change in behaviour for the sample, there is a ?%± e% change in the behaviour of the population, where e is the sampling error. In this paper we present the rationale for an alternative formulation and demonstrate its applicability both hypothetically and then empirically using data from the Puget Sound Transportation Panel. The results have important ramifications both for those implementing future behaviour change programs and those interpreting the results reported in previous studies

Commercial vehicle tour data collection using passive GPS technology: Issues and potential applications

In mid-2006 a GPS survey of commercial vehicles was piloted in Melbourne, Australia to support a major update of freight data and modelling capabilities in the metropolitan region. This survey marked the first of its kind in Australia, and to the best of the authors’ knowledge, one of the first world-wide. This paper presents the issues surrounding the collection and use of GPS data as a method to provide information on commercial vehicle tours within an urban setting. The paper focuses on passive GPS methods where the truck driver’s involvement in the data collection effort is minimal. We address (a) implementation issues with the data collection, (b) the algorithms used to process the raw GPS data into meaningful trip tour information, (c) pilot survey data tour results, and (d) potential uses and limitations of passive GPS technology in urban freight modelling and planning. Despite processing challenges, GPS provides an appealing method to enrich commercial vehicle data collection and enhance our understanding of on-road behaviour. As increasing numbers of commercial vehicles become equipped with GPS receivers, we argue only privacy concerns remain as a major barrier to gathering and using such data on a wide-spread basis in the future

Comparing two processing routines for GPS traces: Lessons learnt

This paper describes what may be one of the first side-by-side tests of two alternative software products for processing GPS traces into trips, and discusses some lessons learnt from the comparisons. For GPS to be useful as an alternative to self-report survey mechanisms, it is imperative that good processing software becomes available to reduce the data streams from the GPS devices into specific trips, with the various attributes of trips that are needed for modelling purposes. Currently, a number of agencies and researchers around the world have developed alternative software products, but none of these are generally open source, and comparisons between them are almost non-existent, although most make claims to certain levels of accuracy. In this paper, we describe an exercise in which two software products were used on the same GPS data set, following which a detailed comparison was made of the results. While it is interesting to see, overall, the accuracy differences between the two software products, what is of even more interest is the lessons that can be learnt about processing software in general. The paper draws some conclusions about the directions forward for processing software and processing routines in general

Collecting longitudinal data from freight operators: survey design and implementation

Freight transport research has generally been limited by a lack of data of the breadth and quality available for passenger transport, particularly in terms of behavioural data. Although there are a number of reasons for this lack of data, the challenges of collecting freight data including the expense, participant burden and confidentiality issues are amongst the most significant. Although some improvements in technology and survey design have allowed for the collection of more behavioural freight data more improvements would be beneficial. This paper discusses the survey design and implementation of a survey intended to collect longitudinal behavioural data on the responses of freight transport firms to the introduction of environmental policies. The design of the survey is centred around a hypothetical scenario where respondents are asked how they would complete a given freight task within common constraints including time windows and delivery requirements. One of the key components of the survey design is a dynamic component that is intended to simulate the changing business environment to which firms are required to adapt. This paper also looks at the participant burden involved in completing the survey and compares how this differs depending on how respondents completed the survey

Electronic ticketing systems as a mechanism for travel behaviour change? Evidence from Sydney’s Opal Card

Smartcard and other forms of electronic ticketing have become integral to modern public transport systems. While aggregate ridership figures have generally been positive, little is known about the drivers behind these changes because of a lack of travel information on individuals before and after implementation of such systems. This working paper presents analysis from a naturalistic travel behaviour study of inner-city Sydney residents that coincided with the phased introduction of the Opal smartcard system. Using a differences-in-differences methodology, results indicate significant reductions in car use of around 10 minutes/day with commensurate increases in train use and incidental walking. This trend holds across income groups and is more pronounced for older residents. Results add further weight to the merits of simplifying ticket purchasing as part of a package of policy measures designed to increase public transport usage

Who stays and who plays? Participant retention and smartphone app usage in a longitudinal travel survey.

Longitudinal studies have become increasingly popular for investigating changes in behaviour, but present additional challenges around participant recruitment, retention, compliance, and ultimately data quality. Personal technologies, particularly smartphones, have become integral to tackling these challenges but come with their own caveats around user acceptance and compliance. The current paper investigates these issues in the context of a longitudinal investigation of interventions designed to encourage use of public transport and increase associated physical activity in Tasmania, Australia. The study comprises multiple waves of data collection over a seven-month period in which travel data were collected using a smartphone app and supplemented with user experience surveys. Evidently attrition is lower for older participants, those engaging with the app more, and those responding to the research/environmental/health messaging of the survey as well as the potential for financial gain. App usage is lower among older participants while app engagement is stronger for males, those recording less travel and those indicating environmental reasons as a motivator for completing the study. Experiences with the app were mixed, participants reported positive sentiments about the ease of use, hedonic motivation, and help in recalling travel; however, concerns were raised over the accuracy of trip recording, the associated burden of correcting trips, and reductions in smartphone battery-life. Despite the unplanned coincidence with the COVID-19 restrictions, outcomes provide important guidance around recruitment, retention and post-hoc analysis of results from longitudinal studies

Interlaboratory comparison study of Mg/Ca and Sr/Ca measurements in planktonic foraminifera for paleoceanographic research

Thirteen laboratories from the USA and Europe participated in an intercomparison study of Mg/Ca and Sr/Ca measurements in foraminifera. The study included five planktonic species from surface sediments from different geographical regions and water depths. Each of the laboratories followed their own cleaning and analytical procedures and had no specific information about the samples. Analysis of solutions of known Mg/Ca and Sr/Ca ratios showed that the intralaboratory instrumental precision is better than 0.5% for both Mg/Ca and Sr/Ca measurements, regardless whether ICP-OES or ICP-MS is used. The interlaboratory precision on the analysis of standard solutions was about 1.5% and 0.9% for Mg/Ca and Sr/Ca measurements, respectively. These are equivalent to Mg/Ca-based temperature repeatability and reproducibility on the analysis of solutions of ±0.2°C and ±0.5°C, respectively. The analysis of foraminifera suggests an interlaboratory variance of about ±8% (%RSD) for Mg/Ca measurements, which translates to reproducibility of about ±2–3°C. The relatively large range in the reproducibility of foraminiferal analysis is primarily due to relatively poor intralaboratory repeatability (about ±1–2°C) and a bias (about 1°C) due to the application of different cleaning methods by different laboratories. Improving the consistency of cleaning methods among laboratories will, therefore, likely lead to better reproducibility. Even more importantly, the results of this study highlight the need for standards calibration among laboratories as a first step toward improving interlaboratory compatibility

A simple rule governs the evolution and development of hominin tooth size

The variation in molar tooth size in humans and our closest relatives (hominins) has strongly influenced our view of human evolution. The reduction in overall size and disproportionate decrease in third molar size have been noted for over a century, and have been attributed to reduced selection for large dentitions owing to changes in diet or the acquisition of cooking1, 2. The systematic pattern of size variation along the tooth row has been described as a ‘morphogenetic gradient’ in mammal, and more specifically hominin, teeth since Butler3 and Dahlberg4. However, the underlying controls of tooth size have not been well understood, with hypotheses ranging from morphogenetic fields3 to the clone theory5. In this study we address the following question: are there rules that govern how hominin tooth size evolves? Here we propose that the inhibitory cascade, an activator–inhibitor mechanism that affects relative tooth size in mammals6, produces the default pattern of tooth sizes for all lower primary postcanine teeth (deciduous premolars and permanent molars) in hominins. This configuration is also equivalent to a morphogenetic gradient, finally pointing to a mechanism that can generate this gradient. The pattern of tooth size remains constant with absolute size in australopiths (including Ardipithecus, Australopithecus and Paranthropus). However, in species of Homo, including modern humans, there is a tight link between tooth proportions and absolute size such that a single developmental parameter can explain both the relative and absolute sizes of primary postcanine teeth. On the basis of the relationship of inhibitory cascade patterning with size, we can use the size at one tooth position to predict the sizes of the remaining four primary postcanine teeth in the row for hominins. Our study provides a development-based expectation to examine the evolution of the unique proportions of human teeth

The effectiveness and cost-effectiveness of a participative community singing programme as a health promotion initiative for older people: protocol for a randomised controlled trial

Background The growth in numbers of older people represents a considerable cost to health and social care services in the United Kingdom. There is an acknowledged need to address issues of social exclusion and both the physicial and mental health of this age group. In recent years there has been much interest in the potential contribution of the arts to the health of communities and individuals. There is some evidence that participative singing may be of benefit to older people, however studies to date are limited in number and have lacked rigour. There is therefore a need to build on this knowledge base to provide more quantifiable evidence of both effectiveness and cost efffectness of singing as a health intervention of this population group. Methods The proposed study is a pragmatic randomised controlled trial with two parallel arms. The primary hypothesis is that singing groups for older people improve both physical and mental aspects of qualaity of life when compared to usual activities. Potential participants will be volunteers over 60 years living in the community and recruited through publicity. Eligible and consenting participants will be randomized to either a singing group or a control group. Singing groups will take part in a twelve week planned programme of singing and control groups will continue with usual activities. The primary outcome measure will be the York SF-12, a health related quality of life measure which will be administered at baseline, three and six months after baseline. The study will evaluate both effectiveness and cost-effectiveness. Discussion This study proposes to add to the exisiting body of evidence on the value of singing for older people by using a rigorous methodological design, which includes a power calucation, a standardised intervention and assessment of cost-effectiveness. It should be regarded as a stage in a progressive programme of studies in this area. If group singing is found to be effective and cost-effective it may offer an alternative means to maintaining the health of people in later life