Children's personal exposure to air pollution in rural villages in Bhutan

Abstract

Exposure assessment studies conducted in developing countries have been based on fixed-site monitoring to date. This is a major deficiency, leading to errors in estimating the actual exposures, which are a function of time spent and pollutant concentrations in different microenvironments. This study quantified school children's daily personal exposure to ultrafine particles (UFP) using real-time monitoring, as well as volatile organic compounds (VOCs) and NO2 using passive sampling in rural Bhutan in order to determine the factors driving the exposures. An activity diary was used to track children's time activity patterns, and difference in mean exposure levels across sex and indoor/outdoor were investigated with ANOVA. 82 children, attending three primary schools participated in this study; S1 and S2 during the wet season and S3 during the dry season. Mean daily UFP exposure (cm(-3)) was 1.08×10(4) for children attending S1, 9.81×10(3) for S2, and 4.19×10(4) for S3. The mean daily NO2 exposure (µg m(-3)) was 4.27 for S1, 3.33 for S2 and 5.38 for S3 children. Likewise, children attending S3 also experienced higher daily exposure to a majority of the VOCs than those attending S1 and S2. Time-series of UFP personal exposures provided detailed information on identifying sources of these particles and quantifying their contributions to the total daily exposures for each microenvironment. The highest UFP exposure resulted from cooking/eating, contributing to 64% of the daily exposure, due to firewood combustion in houses using traditional mud cookstoves. The lowest UFP exposures were during the hours that children spent outdoors at school. The outcomes of this study highlight the significant contributions of lifestyle and socio-economic factors in personal exposures and have applications in environmental risk assessment and household air pollution mitigation in Bhutan.

Exposure to ultrafine particles in children until 18 years of age: A systematic review

“…The measuring periods in most of the studies were 24 or 48 hours . Conversely, the analysis periods of Wangchuk et al (2015), Leaffer et al, and both studies carried out by Dirks et al were shorter: 8 hours on three consecutive days, 3 hours during seven winter days and seven summer days, and only the time during transportation to school, respectively (Table ).…”

“…Of the 32 articles that fulfilled our criteria, 22 quantified UFP levels in children's specific microenvironments (Table ; Figure and ), while the other 10 studies that were selected measured children's personal exposure to UFP by means of active samplers carried by children (Table ; Figure ). Among the studies regarding microenvironment exposures, 18 (82%) referred to UFP levels in schools or nurseries, 3 referred to transport (2 to schools and 1 to baby prams), 1 considered the UFP levels in heavily trafficked streets, and 2 measured levels in homes .…”

“…Most of the studies were carried out in Europe: 4 in Italy, 2 in Greece, 5 in Portugal, 1 in France, 2 in United Kingdom, and 5 in Spain . Five were conducted in Oceania (Australia and New Zealand), 7 in America (5 in United States and 2 in Canada), and 3 in Asia (Bhutan, Korea, and Indonesia) . All the articles considered in this review measured the levels of ultrafine particles as part/cm .…”

“…Pañella et al determined personal exposure of asthmatic and non‐asthmatic children to UFP. Wangchuk et al estimated personal exposure of children from three different schools in Bhutan situated at three altitudes (1400, 1600, and 1900 m) and under different traffic conditions. Buonanno et al, Mazaheri et al Paunescu et al and Leaffer et al analyzed the personal exposure of children without dividing them into groups (Table ).…”

Temporal Characteristics of Selected Volatile Organic Compounds in Urban High-Stories Urban Apartments

“…Consistently, other research groups (Park and Ikeda, 2006;Tuomainen et al, 2003) observed that certain VOC indoor concent -rations decreased gradually over 3-y follow-up periods. In addition, a great deal of research groups reported that indoor VOC concentrations were typically higher than outdoor VOC concentrations in residential, school, hair salon, and office buildings (Cometto-Muñiz and Abraham, 2015;de Gennaro et al, 2014;Do et al, 2015;Gokhale et al, 2008;Mishra et al, 2015;Su et al, 2013;Uchiyama et al, 2015;Wangchuk et al, 2015). Table 3 reveals the emission rates of 9 selected VOCs (2E1H, EOL, 1POL, 2POL, DCA, NNA, ACT, 2BT, and 4M2P) estimated for the investigated apartments according to survey period.…”