Different Times, Different Places, Different Standpoints

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Ions in motor vehicle exhaust and their dispersion near busy roads

Measurements in the exhaust plume of a petrol-driven motor car showed that molecular cluster ions of both signs were present in approximately equal amounts. The emission rate increased sharply with engine speed while the charge symmetry remained unchanged. Measurements at the kerbside of nine motorways and five city roads showed that the mean total cluster ion concentration near city roads (603 cm-3) was about one-half of that near motorways (1211 cm-3) and about twice as high as that in the urban background (269 cm-3). Both positive and negative ion concentrations near a motorway showed a significant linear increase with traffic density (R2=0.3 at p<0.05) and correlated well with each other in real time (R2=0.87 at p<0.01). Heavy duty diesel vehicles comprised the main source of ions near busy roads. Measurements were conducted as a function of downwind distance from two motorways carrying around 120-150 vehicles per minute. Total traffic-related cluster ion concentrations decreased rapidly with distance, falling by one-half from the closest approach of 2m to 5m of the kerb. Measured concentrations decreased to background at about 15m from the kerb when the wind speed was 1.3 m s-1, this distance being greater at higher wind speed. The number and net charge concentrations of aerosol particles were also measured. Unlike particles that were carried downwind to distances of a few hundred metres, cluster ions emitted by motor vehicles were not present at more than a few tens of metres from the road

Studying International Migration in the Long(er) and Short(er) Duree: Contesting Some and Reconciling Other Disagreements Between the Structuration and Morphogenetic Approaches

The essay contests some and reconciles other disagreements between the structuration and morphogenesis approaches?the two models in present-day sociology which aim at bridging the macro-micro gap in social theorizing, but whose advocates have been either indifferent to or at open odds which each other instead of engaging in a close intellectual collaboration. The empirical illustrations of my arguments come from local statistical surveys and ethnographic studies conducted in Polish villages from the onset to the decline of mass transatlantic migration in the period 1870s-1930s

Spatial variation of particle number concentration in school microscale environment

There is significant toxicological evidence of the effects of ultrafine particles (<100nm) on human health (WHO 2005). Studies show that the number concentration of particles has been associated with adverse human health effects (Englert 2004). This work is part of a major study called ‘Ultrafine Particles form Traffic Emissions and Children’s Health’ (UPTECH), which seeks to determine the effect of the exposure to traffic related ultrafine particles on children’s health in schools (http://www.ilaqh.qut.edu.au/Misc/UPT ECH%20Home.htm). Quantification of spatial variation of particle number concentration (PNC) in a microscale environment and identification of the main affecting parameters and their contribution levels are the main aims of this analysis

Application of bag sampling technique for particle size distribution measurements

Bag sampling techniques can be used to temporarily store an aerosol and therefore provide sufficient time to utilize sensitive but slow instrumental techniques for recording detailed particle size distributions. Laboratory based assessment of the method were conducted to examine size dependant deposition loss coefficients for aerosols held in VelostatTM bags conforming to a horizontal cylindrical geometry. Deposition losses of NaCl particles in the range of 10 nm to 160 nm were analysed in relation to the bag size, storage time, and sampling flow rate. Results of this study suggest that the bag sampling method is most useful for moderately short sampling periods of about 5 minutes

Inherent Agency Conflict Built into the Auditor Remuneration Model

This paper provides a model for audit market interventions. The study asks whether interventions in the audit market result in excessive premiums at the cost of quality and independence. The model was tested based on a historical data sample of 1,927 companies’ fiscal year financial statements, observed for the period 2010–2013. The testing strategy combined statistical analysis of the market concentration and regression of abnormal results. The findings do not support, for the Polish market, the conclusion that the audit market is used as a leverage for consulting services. This paper discusses possibilities of systematic risk for policymakers as a result of the negative interaction between regulated and non-regulated markets

Influence of filtration on I/O particle concentration ratios at urban office buildings

Epidemiological research has consistently shown an association between fine and ultrafine particle concentrations, and increases in both respiratory and cardiovascular morbidity and mortality. These particles, often found in vehicle emissions outside buildings, can penetrate inside via their envelopes and mechanically ventilated systems. Indoor activities such as printing, cooking and cleaning, as well as the movement of building occupants are also an additional source of these particles. In this context, the filtration systems of mechanically ventilated buildings can reduce indoor particle concentrations. Several studies have quantified the efficiency of dry-media and electrostatic filters, but they mainly focused on the particle size range > 300 nm. Some others studied ultrafine particles but their investigations were conducted in laboratories. At this point, there is still only limited information on in situ filter efficiency and an incomplete understanding of filtration influence on I/O ratios of particle concentrations. To help address these gaps in knowledge and provide new information for the selection of appropriate filter types in office building HVAC systems, we aimed to: (1) measure particle concentrations at up and down stream flows of filter devices, as well as outdoor and indoor office buildings; (2) quantify efficiency of different filter types at different buildings; and (3) assess the impact of these filters on I/O ratios at different indoor and outdoor source operation scenarios

Application of aerosol electrometer for ambient particle charge measurements

The charge on ambient atmospheric particles is an important parameter in the investigation of particle dynamics. Yet, there is only limited knowledge available on it, mainly due to the lack of instrumentation for its direct measurement. The aim of this study was to explore the application and suitability of the Aerosol Electrometer (AE) TSI Model 3068 as a direct instrument for measuring ambient particle charge concentration, thereby extending its use beyond the current applications. Through a set of experimental investigations the AE was applied to measure net concentration of charged particles in different environments. Results of the study showed the instrument is mostly suitable for outdoor field measurement, when particle charge concentrations are elevated, such as in the vicinity of strong ion emitting sources (high voltage powerlines, electricity substations, etc); and under conditions of air relative humidity of below 60%. Operating the instrument above this humidity value would require the use of a dehumidifier. 74% (R2) statistical correlation (P<0.05) was obtained between the readings of the AE and the Air Ion Counter, when both instruments were used to simultaneously sample ambient air