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D'Angiola A.,Comision Nacional de la Energia Atomica | D'Angiola A.,National University of San Martin of Argentina | Dawidowski L.E.,Comision Nacional de la Energia Atomica | Dawidowski L.E.,National University of San Martin of Argentina | And 5 more authors.
Atmospheric Environment

A new annual bottom-up emission inventory of criteria pollutants and greenhouse gases from on-road mobile sources was developed for 2006 for the metropolitan area of Buenos Aires, Argentina, within a four-year regional project aimed at providing tools for chemical weather forecast in South America. Under the scarcity of local emission factors, we collected data from measuring campaigns performed in Argentina, Brazil, Chile and Colombia and compiled a data set of regional emission factors representative of Latin American fleets and driving conditions. The estimated emissions were validated with respect to downscaled national estimates and the EDGAR global emission database. Our results highlight the role of older technologies accounting in average for almost 80% of the emissions of all species. The area exhibits higher specific emissions than developed countries, with figures two times higher for criteria pollutants. We analyzed the effect on emissions of replacing gasoline by compressed natural gas, occurring in Argentina since 1995. We identified (i) a relationship between number of vehicles and a compound socioeconomic indicator, and (ii) time-lags in vehicle technologies between developed and developing countries, which can be respectively applied for spatial disaggregation and the development of projections for other Latin American cities. The results may also be employed to complement global emission inventories and by local policy makers as an environmental management tool. © 2009 Elsevier Ltd. All rights reserved. Source

Liu H.,University of California at Riverside | Barth M.,University of California at Riverside | Scora G.,University of California at Riverside | Davis N.,International Sustainable Systems Research Center | Lents J.,International Sustainable Systems Research Center
Transportation Research Record

Portable emission measurement systems (PEMS) are increasingly being used in a variety of transportation research projects to determine the impact of real-world vehicle emissions. One of the key questions that remain is how well these systems perform compared with testing that occurs in controlled laboratory conditions. To help answer this question, three PEMS were carefully evaluated for both gasoline and diesel light-duty vehicles in a dynamometer test facility. The evaluation was focused on the systems' accuracy, time correspondence, and suitability for measuring transient emissions. Both cumulative mass emissions and modal emissions for carbon monoxide (CO), hydrocarbons (HC), oxides of nitrogen (NOx), and carbon dioxide (CO2) were measured for three gasoline and three diesel vehicles on three widely varying driving cycles. All of the PEMS proved to be both reasonably accurate and precise. The CO2 emissions measured by the PEMS were in excellent agreement (within 98%) with measurements from the laboratory system. Other pollutants measured were found to be in reasonable agreement (within 20% or better) for NOx and HC on diesel vehicles and CO on gasoline vehicles. The second-by-second emission rate measured with the PEMS matched well with the corresponding laboratory modal analyzer data for CO2, NOx, and CO under all driving cycles. Transient emissions of all pollutants agreed within 10% of the two systems for more than 6,000 data points from each vehicle. The results suggest that when properly set up and calibrated, PEMS are capable of measuring emissions from both gasoline and diesel vehicles to an accuracy within 20% of conventional laboratory modal analyzer systems. Source

Mena-Carrasco M.,Andres Bello University | Oliva E.,Andres Bello University | Saide P.,University of Iowa | Spak S.N.,University of Iowa | And 7 more authors.
Science of the Total Environment

Chilean law requires the assessment of air pollution control strategies for their costs and benefits. Here we employ an online weather and chemical transport model, WRF-Chem, and a gridded population density map, LANDSCAN, to estimate changes in fine particle pollution exposure, health benefits, and economic valuation for two emission reduction strategies based on increasing the use of compressed natural gas (CNG) in Santiago, Chile. The first scenario, switching to a CNG public transportation system, would reduce urban PM2.5 emissions by 229t/year. The second scenario would reduce wood burning emissions by 671t/year, with unique hourly emission reductions distributed from daily heating demand. The CNG bus scenario reduces annual PM2.5 by 0.33μg/m 3 and up to 2μg/m 3 during winter months, while the residential heating scenario reduces annual PM2.5 by 2.07μg/m 3, with peaks exceeding 8μg/m 3 during strong air pollution episodes in winter months. These ambient pollution reductions lead to 36 avoided premature mortalities for the CNG bus scenario, and 229 for the CNG heating scenario. Both policies are shown to be cost-effective ways of reducing air pollution, as they target high-emitting area pollution sources and reduce concentrations over densely populated urban areas as well as less dense areas outside the city limits. Unlike the concentration rollback methods commonly used in public policy analyses, which assume homogeneous reductions across a whole city (including homogeneous population densities), and without accounting for the seasonality of certain emissions, this approach accounts for both seasonality and diurnal emission profiles for both the transportation and residential heating sectors. © 2012 Elsevier B.V. Source

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