Chemical analysis and statistical study on the composition of airborne particulate matter (PM2.5 and PM10 ), aerosols (PM2.5 ) inorganic trace gases and precipitation in Singapore between 2009 – 2012
Date of Issue2012
School of Physical and Mathematical Sciences
Abstract At a Nanyang Technological University (NTU) rooftop sampling site, airborne particulates were sampled in two different sizes of 10 and 2.5 µm between October 2009 to December 2011. Airborne particulate matter samples were acid digested using a microwave system in closed vessels. The amount of acids, power setting and digestion times were optimized in order to achieve an efficient digestion. An inductively coupled plasma mass spectrometry (ICP-MS) method was developed for the determination of the elemental composition of airborne particulate matter. The developed microwave procedure and ICP-MS method were tested with NIST Standard Reference Material 2783 Urban Particulate Matter based on the recovery test. It was found that major elements were present in the airborne particulate matter with high concentrations (µg m-3) in the order of Na > Ca > Al > K > Mg > Zn > Fe. The enrichment factor (EF) was used as a means to determine whether the elements originated from natural or anthropogenic sources. Their main sources were likely to be anthropogenic, for instance vehicular and industrial emissions. PMF applied to the 54-variable model apportioned the airborne particulate matter into several sources including sea salt, crustal and windblown dust, road dust, vehicular emissions, refineries and chemical industries, electronics and semiconductors, high temperature operations and construction.