Measurement of Fine Particles in Diesel Emissions Using a Real-Time Aerosol Monitor

Abstract

A real-time monitoring methodology to determine diesel fine particles in diesel emissions has been evaluated. The range of particle size captured by the monitor was ～0.1 μm to 1 μm. DustTrak real-time monitors were connected to the dilution tunnel of the vehicle exhaust to measure the emissions during the vehicle tests under both dynamic and steady-state driving conditions, and concentration data were recorded every 5 sec. Test variation of the real-time monitoring among different test days was similar to that measured by traditional filter-based gravi-metric method, whereas the repeatability of the monitor data within the same-day tests was better than that of gravimetric method. Correlations between the two methods were established for different fuels tested on a single light duty vehicle. When the emissions from the reference fuel was used to convert the monitor’s response to diesel fuels, the levels determined by the real-time monitor were consistent with those measured by gravimetric method among different fuels tested. Use of the real-time monitor could provide information on the levels of fine particles that is more relevant to the public health than the total particles.     

Comparison of vehicle exhaust emissions from modified diesel fuels

Three diesel fuels, one oil sand-derived (OSD) diesel serving as base fuel, one cetane-enhanced base fuel, and one oxygenate [diethylene glycol dimethyl ether (DEDM)]-blended base fuel, were tested for their emission characterizations in vehicle exhaust on a light-duty diesel truck that reflects the engine technology of the 1994 North American standard. Both the cetane-enhanced and the oxygenate-blended fuels were able to reduce regulated [CO, particulate matter (PM), total hydrocarbon (THC)] and nonregulated [polyaromatic hydrocarbons (PAHs), carbonyls, and other volatile organic chemicals] emissions, except for nitrogen oxides (NO(x)), compared with the base fuel. Although burning a fuel that contains oxygen could conceivably yield more oxygenated compounds in emissions, the oxygenate-blended diesel fuel resulted in reduced emissions of formaldehyde along with hydrocarbons such as benzene, 1,3-butadiene, and PAHs. Reductions in nitro-PAH emissions have been observed in both the cetane-enhanced and oxygenated fuels. This further demonstrates the benefits of using a cetane enhancer and the oxygenated fuel component.     

Vertical transport of accumulation mode particles between two street canyons and the urban boundary layer

Concentrations and turbulent fluxes of accumulation mode particles were measured during the 2004–2005 ‘Canopy and Aerosol Particle Interaction in Toulouse Urban Layer’ project (CAPITOUL) at the top of two intersecting street canyons and in the urban boundary layer (UBL) in Toulouse, France. Particle numbers were strongly affected by boundary layer depth and showed limited sensitivity to local emissions. Differences in the diurnal patterns of particle numbers were observed between the finer fraction (0.3–0.4 μm) and coarser fraction (1.6–2.0 μm) of accumulation mode particles, indicating different processes of formation, evolution and transportation may be dominant. Highest particle numbers were observed in the narrow street canyon which had more limited local emissions and comparatively small particle fluxes. However, the improved ventilation rate in the wider canyon was also associated with the downward mixing of particles into the street canyon from the UBL. The results from this study clearly illustrate the temporal and spatial variability of particle numbers and fluxes in the urban atmosphere.     

The Leading Canadian NGOs’ Discourse on Fish Farming: From Ecocentric Intuitions to Biocentric Solutions

The development of the aquaculture industry in Canada has triggered a conflict of a scope never seen before. As stated in Young and Matthews’ The Aquaculture Controversy, this debate has “mushroomed over the past several decades to become one of the most bitter and stubborn face-offs over industrial development ever witnessed in Canada” (Young and Matthews in The aquaculture controversy in Canada. Activism, policy and contested science. UBC Press, Vancouver, p 3, 2010). It opposes a wide variety of actors: from industrial investors, scientists, politicians and environmentalists to Native associations and communities, citizens groups and local stakeholders. The opposition is fierce between those in favor of a flourishing and modern aquaculture of industrial nature and those who fear the dreadful consequences of such an industry. In particular, the possible implementation of biotechnology innovations, such as a genetically modified salmon, has made this debate coextensive with the GMO debate, thus multiplying the opposition’s spectrum of arguments against the industry. Throughout the debate, Canadian environmental NGOs like the Suzuki Foundation and Greenpeace Canada have assumed leadership over the opposition to aquaculture development with certain success. Their participation in the debate features numerous ethical concerns related to environmental health, a respect for wilderness and local human communities. Such a position can be associated overall with a form of ecocentric ethics or concern. Nevertheless, a careful examination of the technical solutions proposed by these NGOs reveals their embeddedness in biocentrism. Through the example taken from the Canadian debate on aquaculture development, this paper aims to highlight the conceptual difficulty of enacting ecocentric ethical positions beyond formal arguments. Because ecocentrism implies a true paradigm shift, not only in mentality, but also in the way we conceive our technical interventions in nature, biocentrism remains an important practical method to enact ethical positions related to environmental concerns in public debates.     

Measurement of fine particles in diesel emissions using a real-time aerosol monitor

A real-time monitoring methodology to determine diesel fine particles in diesel emissions has been evaluated. The range of particle size captured by the monitor was approximately 0.1 microm to 1 microm. DustTrak real-time monitors were connected to the dilution tunnel of the vehicle exhaust to measure the emissions during the vehicle tests under both dynamic and steady-state driving conditions, and concentration data were recorded every 5 sec. Test variation of the real-time monitoring among different test days was similar to that measured by traditional filter-based gravimetric method, whereas the repeatability of the monitor data within the same-day tests was better than that of gravimetric method. Correlations between the two methods were established for different fuels tested on a single light duty vehicle. When the emissions from the reference fuel was used to convert the monitor's response to diesel fuels, the levels determined by the real-time monitor were consistent with those measured by gravimetric method among different fuels tested. Use of the real-time monitor could provide information on the levels of fine particles that is more relevant to the public health than the total particles.