GAW Report No. 205 - IGAC Project

CHAPTER 4 – SOUTH AMERICABetween 2000 and 2006, a toll based urban highway was built, which allowed sprawlingsuburbs to connect with the city in substantially less time. The combination of a slow publictransportation system with an efficient highway system may have led previous users of the publictransportation system to buy cars and motorcycles. From 2000 to 2008, the number of cars inSantiago grew by 42% to 1.2 million. This growth in private transportation probably accounts forthe lack of substantial reductions in pollutant levels despite the improvements in fuel and vehicletechnology over the same period. In addition, after 2004, imports of natural gas from Argentinawere restricted forcing industry to reconvert to other liquid fuels, such as petroleum products ordiesel. This caused increased SO 2 and NO X emissions, ultimately leading to increased PM 2.5 yearlymeans for 2007 and 2008. It is hoped that the recent installation of a Liquefied Natural Gasterminal will allow natural gas use to be re-established in Chile. The latest revision of the air qualitypollution prevention programme (2009) includes retrofitting particulate filters in new and old busesand trucks, a scrapping programme for older gasoline and diesel vehicles, introducing a morestringent emission standard for wood burning heaters, banning agricultural burns, and a cap andtrade system for SO 2 and NO X emissions from industry.According to Fuenzalida et al. [2006] who provided the first set of regional present andfuture climate scenarios using dynamical downscaling, the central part of Chile, where Santiago islocated, will see a 40% decline in precipitation, an increase in surface temperatures, and asouthward expansion of the subtropical high. These changes may in turn affect stability andventilation but these aspects were not addressed in this study. One can only speculate that theprobable southward expansion of the arid regime could intensify the radiatively driven circulation inthe Santiago basin, generating more summer like conditions, which are very favourable forphotochemical pollution. If the degree of centralization persists, the expected demographicscombined with a warmer climate may result in increased vulnerability [e.g., Bell et al., 2008].Santiago’s air quality has been subject to multiple studies since, at least, the early 1980’s.Over the years, the amount and the complexity of such studies have increased notoriously. Like inmany other cities in the world, research and management initiatives in Santiago were triggered byacute air pollution problems, in this case very high concentrations of inhalable particles (800 mg/m 3hourly averages in the late 1980’s) and associated respiratory problems that followed fromuncontrolled traffic and urban growth in the mid 70’s [e.g., Romero et al., 1999]. Therefore, theaccent of these initiatives has focused first on reducing extreme pollution events that areresponsible for acute effects and short-term air quality standards. Measures have focused on largeemitters: industries, non-catalytic cars, buses and trucks [e.g., Emmelin et al., 2007; Morales et al.,2006]. Such curbing measures could be identified based on relatively imprecise emissioninventories for criteria pollutants and simple receptor modelling approaches. However, as theattainment objectives become more ambitious (e.g., long-term air quality standards for dealing withaccumulative effects), the need of determining more subtle cost-effective measures and moreprecise tools increases. This, in turn, requires coordinated efforts to provide more of a systemicapproach [e.g., Molina and Molina, 2004].The number of active, highly qualified (PhD) researchers that can contribute to address airquality and climate issues is increasing but it is still insufficient. For instance, according to theChilean Academy of Science, in 2005 there were around 50 active scientists in the area ofanalytical and environmental chemistry, twice as many as in 1997 [Allende et al., 2005]. InAtmospheric Science, there are less than 20 active researchers at PhD level, and this number hasprobably tripled over the last decade. Up to now, the connection between policy making andresearch has been made based on short-term consultancies, which by construction hampers theestablishment of necessary synergies and the study of more complex issues. Hence, it appearsnecessary to create a research consortium able to convey scientists from different disciplines,combining natural and social science, which, in addition to scientific knowledge, is able to provideindependent opinions to environmental authorities. Such consortium could provide a platform forinternational collaboration and capacity building.159