Overestimation of self-reported driving exposure: Results from the SHRP2 Naturalistic Driving Study

Objectives: The accuracy of self-reported driving exposure has questioned the validity of using self-reported mileage to inform research questions. Studies examining the accuracy of self-reported driving exposure compared to objective measures find low validity, with drivers overestimating and underestimating driving distance. The aims of the current study were to (1) examine the discrepancy between self-reported annual mileage and driving exposure the following year and (2) investigate whether these differences depended on age and annual mileage.

Methods: Two estimates of drivers’ self-reported annual mileage collected during vehicle installation (obtained via prestudy questionnaires) and approximated annual mileage driven (based upon Global Positioning System data) were acquired from 3,323 participants who participated in the Strategic Highway Research Program 2 (SHRP2) Naturalistic Driving Study.

Results: A Wilcoxon signed rank test showed that there was a significant difference between self-reported and annual driving exposure during participation in SHRP 2, with the majority of self-reported responses overestimating annual mileage the following year, irrespective of whether an ordinal or ratio variable was examined. Over 15% of participants provided self-reported responses with over 100% deviation, which were exclusive to participants underestimating annual mileage. Further, deviations in reporting differed between participants who had low, medium, and high exposure, as well as between participants in different age groups.

Conclusions: These findings indicate that although self-reported annual mileage is heavily relied on for research, such estimates of driving distance may be an overestimate of current or future mileage and can influence the validity of prior research that has utilized estimates of driving exposure.     

Impact of climate change: an empirical investigation of Malaysian rice production

This paper examines the possible impact of climate change on Malaysian rice production. Using the Ricardian Method and farm household data, we have examined the effects on rice producers focusing on sharecropper adaptations and ecological causes. The principle goal of this research paper is to investigate the impact of climate variables such as temperature, rainfall and precipitation on rice production during main and off seasons, in Kedah, Malaysia. The main purpose of this paper is to examine how climate change affects the net income of paddy farmers in the study area. The statistically significant results show that temperature, rainfall, farm size, educational knowledge, land area and value of labour input have an impact on rice production per hectare revealing potential impacts of climate vulnerability on Malaysian agriculture. The results showed that net revenue increased by Ringgit Malaysia (RM 1= $0.3277) 4.78 per hectare throughout the main seasons as a result of minimal increase in the temperature while there is a decrease of RM 3.02 in the net revenue per hectare during off seasons. During the off season, rainfall increased revenue per hectare by RM 1.32 and during the main season it reduced revenue per hectare by RM 1.01. The evidence from this study may be useful for Malaysian policymakers to facilitate greater preventive measures during the main and off-seasons to counteract climate uncertainty and vulnerability.     

Long-term dispersion and availability of metals from submarine mine tailing disposal in a fjord in Arctic Norway

Mining of Cu took place in Kvalsund in the Arctic part of Norway in the 1970s, and mine tailings were discharged to the inner part of the fjord, Repparfjorden. Metal speciation analysis was used to assess the historical dispersion of metals as well as their potential bioavailability from the area of the mine tailing disposal. It was revealed that the dispersion of Ba, Cr, Ni, Pb and Zn from the mine tailings has been limited. Dispersion of Cu to the outer fjord has, however, occurred; the amounts released and dispersed from the mine tailing disposal area quantified to be 2.5–10 t, less than 5% of Cu in the original mine tailings. An estimated 80–390 t of Cu still remains in the disposal area from the surface to a depth of 16 cm. Metal partitioning showed that 56–95% of the Cu is bound in the potential bioavailable fractions (exchangeable, reducible and oxidisable) of the sediments, totalling approximately 70–340 t, with potential for continuous release to the pore water and re-precipitation in over- and underlying sediments. Surface sediments in the deposit area were affected by elevated Cu concentrations just above the probable effect level according to the Norwegian sediment quality criteria, with 50–80% Cu bound in the exchangeable, reducible and oxidisable fractions, potentially available for release to the water column and/or for uptake in benthic organisms.     

Intermittent agitation of liquid manure: effects on methane,microbial activity,and temperature in a farm-scale study

Liquid manure storages are a significant source of methane (CH₄) emissions. Farmers commonly agitate (stir) liquid manure prior to field application to homogenize nutrients and solids. During agitation, manure undergoes mechanical stress and is exposed to the air, disrupting anaerobic conditions. This on-farm study aimed to better understand the effects of agitation on CH₄ emissions, and explore the potential for intentional agitation (three times) to disrupt the exponential increase of CH₄ emissions in spring and summer. Results showed that agitation substantially increased manure temperature in the study year compared to the previous year, particularly at upper- and mid-depths of the stored manure. The temporal pattern of CH₄ emissions was altered by reduced emissions over the subsequent week, followed by an increase during the second week. Microbial analysis indicated that the activity of archaea and methanogens increased after each agitation event, but there was little change in the populations of methanogens, archaea, and bacteria. Overall, CH₄ emissions were higher than any of the previous three years, likely due to warmer manure temperatures that were higher than the previous years (despite similar air temperatures). Therefore, intermittent manure agitation with the frequency, duration, and intensity used in this study is not recommended as a CH₄ emission mitigation practice.

Implications: The potential to mitigate methane emissions from liquid manure storages by strategically timed agitation was evaluated in a detailed farm-scale study. Agitation was conducted with readily-available farm equipment, and targeted at the early summer to disrupt methanogenic communities when CH₄ emissions increase exponentially. Methane emissions were reduced for about one week after agitation. However, agitation led to increased manure temperature, and was associated with increased activity of methanogens. Overall, agitation was associated with similar or higher methane emissions. Therefore, agitation is not recommended as a mitigation strategy.     

Occupational hygiene in terms of volatile organic compounds (VOCs) and bioaerosols at two solid waste management plants in Finland

Factors affecting occupational hygiene were measured at the solid waste transferring plant at Hyvinkää and at the optic separation plant in Hämeenlinna. Measurements consisted of volatile organic compounds (VOCs) and bioaerosols including microbes, dust and endotoxins.The most abundant compounds in both of the plants were aliphatic and aromatic hydrocarbons, esters of carboxylic acids, ketones and terpenes. In terms of odour generation, the most important emissions were acetic acid, 2,3-butanedione, ethyl acetate, alpha-pinene and limonene due to their low threshold odour concentrations. At the optic waste separation plant, limonene occurred at the highest concentration of all single compounds of identified VOCs. The concentration of any single volatile organic compound did not exceed the occupational exposure limit (OEL) concentration. However, 2,3-butanedione as a health risk compound is discussed based on recent scientific findings linking it to lung disease.Microbe and dust concentrations were low at the waste transferring plant. Only endotoxin concentrations may cause health problems; the average concentration inside the plant was 425 EU/m³ which clearly exceeded the threshold value of 90 EU/m³. In the wheel loader cabin the endotoxin concentrations were below 1 EU/m³. High microbial and endotoxin concentrations were measured in the processing hall at the optic waste separation plant. The average concentration of endotoxins was found to be 10,980 EU/m³, a concentration which may cause health risks. Concentrations of viable fungi were quite high in few measurements in the control room. The most problematic factor was endotoxins whose average measured concentrations was 4853 EU/m³.     

Modeling Nutrient Transports and Exchanges of Nutrients Between Shallow Regions and the Open Baltic Sea in Present and Future Climate

We quantified horizontal transport patterns and the net exchange of nutrients between shallow regions and the open sea in the Baltic proper. A coupled biogeochemical-physical circulation model was used for transient simulations 1961-2100. The model was driven by regional downscaling of the IPCC climate change scenario A1B from two global General Circulation Models in combination with two nutrient load scenarios. Modeled nutrient transports followed mainly the large-scale internal water circulation and showed only small circulation changes in the future projections. The internal nutrient cycling and exchanges between shallow and deeper waters became intensified, and the internal removal of phosphorus became weaker in the warmer future climate. These effects counteracted the impact from nutrient load reductions according to the Baltic Sea Action Plan. The net effect of climate change and nutrient reductions was an increased net import of dissolved inorganic phosphorus to shallow areas in the Baltic proper.     

Diseases and motor vehicle fatalities in Finland in 2001 and 2002

OBJECTIVES: The possible connection between diseases among drivers and traffic accidents was examined for traffic safety purposes. METHODS: We studied medical conditions of drivers and passengers in all motor vehicle crashes with fatalities in Finland in 2001 and 2002 by using reports of road accident investigation teams, including autopsy reports. We analyzed a total of 542 crashes with 640 fatalities. Findings were also compared with available epidemiological data in Finland. RESULTS: An insignificant difference in the number of reported diseases was present between the different parties involved in crashes. However, among killed key drivers, so-called A-parties, psychiatric diseases, especially alcoholism, depression, and unspecific mental disorders, were diagnosed more often than in the groups of other drivers or passengers. In addition, A-parties were reported to more frequently suffer from cerebral arteriosclerosis and arterial hypertension. CONCLUSIONS: Drivers' diseases can be a risk factor for traffic accidents. Fitness to drive should therefore be considered in medical practice, particularly in patients with alcoholism and other psychiatric disorders.