AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
2013 Southeast Asian Smoke Haze: Speciation of Size-resolved Aerosols and Associated Health Impacts
RAJASEKHAR BALASUBRAMANIAN, Raghu Betha, Sailesh Behera, National University of Singapore
Abstract Number: 6 Working Group: Biomass Burning Aerosol: From Emissions to Impacts
Abstract Occurrence of biomass burning-induced smoke haze has become an annual phenomenon in tropical South East Asia (SEA) over the past several decades, but with different duration, intensity and impacts depending on prevailing weather conditions. Uncontrolled forest and peat land fires resulting from land clearing activities in Indonesia release large amounts of airborne particulate matter (PM) with unique chemical composition into the atmosphere. The resultant PM emissions from these wild fires are transported by trans-boundary winds and transformed into regional haze episodes affecting several countries in SEA, most notably, Singapore, Malaysia, Indonesia and Thailand. One of the worst haze episodes in the history of SEA occurred in June 2013. Size-segregated particulates (2.5 – 1.0 µm; 1.0 – 0.5 µm; 0.5 – 0.2 µm and < 0.2 µm) were collected during both hazy and non-hazy periods, and subjected to chemical fractionation of particulate-bound trace elements (B, Ca, K, Fe, Al, Ni, Zn, Mg, Se, Cu, Cr, As, Mn, Pb, Co, Cd). PM2.5 concentrations were elevated (up to 329 µg/m3) during the haze episode, compared to those during the non-haze period (11 – 21 µg/m3). There was a 10-fold increase in the concentration of K, an inorganic tracer of biomass burning. A major fraction (>60%) of the elements was present in oxidizable and residual fractions while the bio-available fraction accounted for up to 20% for most of the elements except K and Mn. Deposition of inhaled potentially toxic trace elements in various regions of the human respiratory system was estimated using a Multiple-Path Particle Dosimetry model. The particle depositions in the respiratory system tend to be more severe during hazy days than those during non-hazy days. A prolonged exposure to finer particles can cause adverse health outcomes during hazy days as revealed by quantified risk analysis.