Personal level exposure and hazard potential of particulate matter during haze and non-haze periods in Singapore. (March 2020)

• Record Type: Journal Article
• Authors: George, Saji; Chua, Mei Ling; ZheWei, Dyan Zhang; Das, Reshmi; Bijin, Veonice AU; Connolly, John E.; Lee, Khai Pin; Yung, Chee Fu; Teoh, Oon Hoe; Thomas, Biju
• Is Part Of: Chemosphere. Volume 243(2020)
• Publication Date: 2020-03
• Subjects: Singapore -- Haze -- Particulate matter -- Personal-exposure -- School-children -- Cytotoxicity; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2019.125401
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Severe haze episodes originating from biomass burning are common in Southeast Asia. However, there is a paucity of data on the personal exposure and characteristics of Particulate Matter (PM) present in ambient air during haze and non-haze periods. Aims of this study were to monitor 24 h ambulatory exposure to PM among school children in Singapore; characterize haze and non-haze PM for their physicochemical properties, cytotoxicity and inflammatory potential, using bronchial epithelial cell culture model (BEAS-2B). Forty-six children had ambulatory PM exposure monitored using portable Aethalometer and their hourly activity recorded. The mean (±SE) PM exposure on a typical school day was 3343 (±174.4) ng/m 3 /min. Higher PM exposure was observed during haze periods and during commuting to and from the school. Characterization of PM collected showed a drastic increase in the proportion of ultrafine particle (UFP) in haze PM. These PM fraction showed higher level of sulphur, potassium and trace metals in comparison to those collected during non-haze periods. Dose dependent increases in abiotic reactive oxygen species generation, activation of NF-κB and cytotoxicity were observed for both haze and non-haze PM. Generally, haze PM induced significantly higher release of IL-6, IL-8 and TNFα by BEAS-2B cells in comparison to non-haze PM. In summary, this study provides experimental evidence for higher PM exposure during haze period which has the potential to elicit oxidative stress and pro-inflammatory cytokine release from airway epithelial cells. Highlights: Personal level exposure to ambient PM increases in school going children during haze periods in Singapore. The proportion of ultrafine particle content was substantially higher in PM collected during haze periods. The smaller haze PM (PM0.25-0.5 ) showed crystal-like morphology, rich in sulphur, potassium and trace metals. A dose dependent abiotic Reactive Oxygen Species (ROS) response, activation of NF-κB and decrease in cell viability was observed with both haze and non-haze PM, while PM induced release of IL-6, IL-8 and TNFα by BEAS-2B cells was significantly higher with haze PM.