2013 Southeast Asian Smoke Haze: Fractionation of Particulate-Bound Elements and Associated Health Risk

Abstract

Recurring biomass burning-induced smoke haze is a serious regional air pollution problem in Southeast Asia (SEA). The June 2013 haze episode was one of the worst air pollution events in SEA. Size segregated particulate samples (2.5-1.0 μm; 1.0-0.5 μm; 0.5- 0.2 μm; and <0.2 μm) were collected during the June 2013 haze episode. PM2.5 concentrations were elevated (up to 329 μg/m(3)) during the haze episode, compared to those during the nonhaze period (11-21 μg/m(3)). Chemical fractionation of particulate-bound trace elements (B, Ca, K, Fe, Al, Ni, Zn, Mg, Se, Cu, Cr, As, Mn, Pb, Co, and Cd) was done using sequential extraction procedures. 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 bioavailable (exchangeable) 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 nonhazy days. A prolonged exposure to finer particles can thus cause adverse health outcomes during hazy days. Health risk estimates revealed that the excessive lifetime carcinogenic risk to individuals exposed to biomass burning-impacted aerosols (18 ± 1 × 10(-6)) increased significantly (P < 0.05) compared to those who exposed to urban air (12 ± 2 × 10(-6)).

Dominant contribution of oxygenated organic aerosol to haze particles from real-time observation in Singapore during an Indonesian wildfire event in 2015

“…Phys. and only 1-4% of the fine aerosol mass are in the size range of 1.0-2.5 m (Betha et al, 2014). Hence, the mass difference found in this study (0.2-0.3%) could not solely be attributed to particles with an aerodynamic diameter between 1 and 2.5 m that were not measured in this study.…”

“…On the other hand, particles in the size range of 0.5-1.0 m was a notable contributor (8-17%) to the total fine aerosol mass during haze episode (Betha et al, 5 2014). Hence, the low collection efficiency for size ranges of 0.5-1.0 m might cause the ToF-ACSM measured less PM 1 mass than previous observation (~97% of PM 2.5 mass; Betha et al, 2014).…”

“…Towards the end of the sampling period (October 29-31), the wind direction shifted, transporting air masses from northeast and east of Singapore. Air masses during this period might have been more dominated by local emissions as well as regional emissions from Malaysia and the South China Sea (e.g., ships emission and sea spray) (Betha et al, 2014). Therefore, we classified the 10 measurements period into Period 1 (P1: for October 10-28), and Period 2 (P2: for October 29-31) in accordance with the wind directions, respectively.…”

Potential health risk for residents around a typical e-waste recycling zone via inhalation of size-fractionated particle-bound heavy metals

“…where DF i is the deposition efficiency of particles in each region; C i is the metal concentration in each particle size (ng m −3 ); and IR is the inhalation rate assumed to be 10 m 3 d −1 for children and 20 m 3 d −1 for adults under normal conditions [18,19]. Because most human activities occur at approximately 1.5 m above the ground, concentrations of heavy metals at the 1.5-m height were used to calculate deposition fluxes in the present study.…”

“…Enrichment factor (EF) has been used to diagnose airborne particle-bound heavy metals from the crustal or anthropogenic origins [18,28], i.e.,…”