GAW Report No. 205 - IGAC Project

CHAPTER 4 – SOUTH AMERICAbeyond mere numbers and it provides a more mechanistic approach in which the methodology istransparent to the (authorized) users.The air quality monitoring network of Aburrá Valley retrieves continuously data collected byautomated instruments. Elevated particulate matter concentrations are of concern, often exceedingthe new Colombian annual standard of 50 mg/m 3 . For instance, in 2008, annually averaged PM 10concentrations were above 50 mg/m 3 at 8 out of 10 stations. In addition, annually averaged PM 2.5concentrations, measured at four sites, were about 30 mg/m 3 . The ozone hourly standard of61ppbv and 8-hour standard of 41 ppbv standards are also frequently surpassed. Available airquality data shows the close relationship between fuel consumption and vehicle emissions of PM 10and PM 2.5 , since the maximum hourly concentrations are occur during rush-hour traffic.The national air quality network (SISAIRE, http://www.siac.gov.co) is a potentially usefultool for air quality management but it must be fed with reliable data collected in a standardizedmanner and subject to strict validation and analysis procedures. Such procedures and standardsrequire further work from the community in Colombia.A notorious decline in sulphur content in diesel fuel took place in 2008 when it was loweredfrom 3200 ppm to 2127 ppm. In 2010, diesel sulphur content was reduced again to 500 ppmthroughout all of Colombia and it is expected to be lowered to 50 ppm by 2013. Given thesignificant contribution of diesel use to mobile emissions, these measures should result in alowering of particulate matter levels in the Aburrá Valley, and elsewhere in Colombia.Observed high concentrations of PM 2.5 are linked to transportation, mainly diesel vehicleswith very old technologies. Ozone precursors are also associated to mobile sources. Hence, abetter characterization of mobile emissions is required. This will in turn require locallyrepresentative emission factors and better measurement capabilities.4.6 SANTIAGO, CHILESantiago, Chile is located at 33˚27’S and 70˚40’W at an altitude of 500 m.a.s.l with apopulation of ~6 million inhabitants. The city of Santiago is located in a semi-arid basin (annualrainfall