Open Collections

Nerpio, Chelsea; Le, Tu Phuong (Phoenix); Wan, Wai Kit (Ricky); Chung, Min Sub (Michael)

The Integrated Solid Waste Management Plan (ISWRM) approved by the Metro Vancouver Board in 2010 and by the BC Province in 2011, recommends waste-to-energy recovery in lieu of landfilling to address the remaining 1.0 million tonnes of garbage being disposed of every year. The recommendation comes with the expectation that this method will reduce waste and generate energy from incineration while reducing the cost of disposal. Although, there are a number of methods that can be implemented to control emissions emitted by waste-to-energy incinerators, certain pollutants such as NOx are more dificult to filter and therefore, remains a concern to the air quality in the Lower Fraser Valley (LFV) - specifically to the formation of ground-level ozone. The dispersion and deposition of NOx in the LFV is strongly governed by the unique topography and proximity to the Pacific Ocean where large-scale sea breezes, valley and slope circulation play an important role in pollutant transport (Douglas and Kessler, 1991; McKendry et al., 1998). However, it is this unique topography of the valley that makes it difficult to predict the transport and deposition of pollutants. As a result, to understand and evaluate the potential for ozone formation due to NOx emissions, three considerations were made: 1. NOx effects on ozone formation given different release points 2. The trajectories of the pollutant released from the different release points 3. NOx effects on ozone formation with respect to the NOx- and VOC- limited regions Land-use development maps were consulted to locate potential sites within New Westminster, Burnaby, Surrey, Tsawwassen, and Gold River. Site characteristics similar to the current Burnaby Waste-to- Energy Facility (WTEF) such as low vegetation, no tree, buffer zones, and access to major roads were taken into account in the siting of the proposed incinerator. Based on these guidelines, seven potential sites were identified as plausible for the WTEF development - one in New Westminister, Tsawwassen, Gold River, and two in Surrey and Burnaby (refer to section 3 for details). The coordinates for each potential site was then applied to the HYbrid Single Particle Lagrangian Integrated Trajectory model (HYSPLIT) to estimate the particle emission trajectories from meteorological fields produced by the Weather Research and Forecasting (WRF) model. Ozone episodes in 1985, 1995, 2001, and 2006 (Steyn et al., 2013) representing the four common meteorological regimes consistent with previous research observations were then used as input for HYSPLIT to simulate trajectories for the seven potential WTEF sites (refer to Table 1C for model inputs summary). Consequently, four HYSPLIT runs were performed over a 72-hour period for each ozone episode at each location for a total of 28 runs (see Figure A for example). Given that the processes to form ground-level ozone - as a result of NOx emissions - are dependent on regions of low NOx (NOx-limited) vs. high NOx concentration (VOC-limited), the methods outlined in Steyn et al. (2013) and Ainslie et al. (2013) were used to establish the NOx/VOC boundary. Regions to the left of the boundary was found to be VOC-limited while right of the boundary is NOx-limited. In order to evaluate the potential for ozone formation due to NOx emissions, the NOx/VOC boundary was first superimposed onto the HYSPLIT trajectory (Figure A). Afterwards, an area within the LFV defined as being NOx-limited was selected (black outline). Figure A: [image omitted] Example of a HYSPLIT run. Daytime trajectories (06:00-18:00) are represented b y red dots and the nighttime trajectories are represented by blue dots (19:00-05:00). The N Ox/VOC boundaries are represented in green (2005) and purple (1985). The triangular a rea, outlined in a solid black line defines the sampling area. To quantitatively rank each location, we counted all the daytime trajectories (red dots) located within the defined area since photochemical formation of ozone only occurs when sunlight is present. Although each year represents a different meteorological regime, the sum of these four regimes provides a general description of the meteorological conditions experienced in the Greater Vancouver Area. Hence, the sum of the counts of all years at each location serves as a representative of the likelihood that emissions released from the potential locations will travel into the NOx-limited region and form ground-level ozone. Using this method, Surrey Two ranked the highest in likelihood and Gold River the lowest. In addition, analysis of hourly ozone concentrations at key monitoring stations throughout the LFV were found that in general, regional-scale processes affected the upper percentiles and Canada-wide standards while local and global scale processes affected the lower percentiles. Consequently, given the different potential WTEF sites, trajectory paths, the NOx/VOC boundary, and our understanding of the global, regional, and local influences on ozone concentration, it can be suggested that additional NOx from the west will impact concentrations at locations located further east into the valley and downwind from major urban NOx sources. This means that the decreasing trend observed on the hourly concentrations at the upper percentiles will reverse trend and most likely induce exceedances of the Canada-wide standards. This is particularly crucial for municipalities such as Hope and Chilliwack located further east into the LFV and have a long record of attaining the CWS for ozone. However, Metro Vancouver’s emissions inventory (Metro Vancouver, 2007) reveal that WTEF emissions contribute less NOx compared to other mobile sources such as light/heavy duty vehicle, marine, railways and off-road vehicles. Hence, in an effort to improve air quality in the LFV, we recommend continuous reductions of NOx in Metro Vancouver especially to the projected increase in marine emissions, research into other options of waste diversion before pursuing WTEF and update management plans to address unique local sources. [This report was modified, October 2013.]

Text

University of British Columbia. ENVR 400

Vancouver : University of British Columbia Library

10.14288/1.0074564

Science, Faculty of; Earth and Ocean Sciences, Department of

Unreviewed

http://creativecommons.org/licenses/by-nc-nd/4.0/