Children’s Indoor Exposures to (Ultra)Fine Particles in an Urban Area: Comparison Between School and Home Environments

Abstract

Due to their detrimental effects on human health, scientific interest in ultrafine particles (UFP), has been increasing but available information is far from comprehensive. Children, who represent one of the most susceptible subpopulation, spend the majority of time in schools and homes. Thus, the aim of this study is to (1) assess indoor levels of particle number concentrations (PNC) in ultrafine and fine (20-1000 nm) range at school and home environments and (2) compare indoor respective dose rates for 3-to 5-yr-old children. Indoor particle number concentrations in range of 20-1000 nm were consecutively measured dur-ing 56 d at two preschools (S1 and S2) and three homes (H1-H3) situated in Porto, Portugal. At both preschools different indoor microenvironments, such as classrooms and canteens, were evaluated. The results showed that total mean indoor PNC as determined for all indoor microenvironments were significantly higher at S1 than S2. At homes, indoor levels of PNC with means ranging between 1.09 × 10 4 and 1.24 × 10 4 particles/cm 3 were 10-70% lower than total indoor means of preschools (1.32 × 10 4 to 1.84 × 10 4 particles/cm 3 ). Nevertheless, estimated dose rates of particles were 1.3-to 2.1-fold higher at homes than preschools, mainly due to longer period of time spent at home. Daily activity patterns of 3-to 5-yr-old children significantly influenced overall dose rates of particles. Therefore, future studies focusing on health effects of airborne pollutants always need to account for children's exposures in different microenvironments such as homes, schools, and transportation modes in order to obtain an accurate representation of children overall exposure.

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

“…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 . Two of the studies assessed exposure in more than one microenvironment …”

“…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 . Two of the studies assessed exposure in more than one microenvironment …”

“…Graphic representation of the levels of UFP measured in schools. It differentiates between the levels in urban and metropolitan areas, and whether the measures are inside the buildings or outside . I, Inside; O, Outside; R, Rural area; U/M, Urban/metropolitan area.…”

“…Graphic representation of the levels of UFP measured in different microenvironments (houses and transport). It differentiates between the levels in urban and metropolitan areas (U/M), and whether the measures are inside (I) the buildings or outside (O); the time of measurement (morning or afternoon); the height of measurement (in meters); or how old the bus is . I, Inside; O, Outside; R, Rural area: U/M, Urban/metropolitan area.…”

Number Concentrations and Modal Structure of Indoor/Outdoor Fine Particles in Four European Cities

“…Indoor aerosols originate both from the outdoor environment and from indoor sources (Jones 1999), with the effect of the latter being particularly important and resulting in PM concentrations higher than outdoors (Hussein et al, 2005;Wallace et al, 2006). The health effects of indoor aerosols are not yet well characterized and their consequences on humans depend on many factors such as type of indoor environment, chemical composition of aerosol, duration of exposure and physical characteristics of the exposed individuals (Lai et al, 2004;Cheng et al, 2012;Beko et al, 2015;Slezakova et al, 2015;Spilak et al, 2015;Sunyer et al, 2015).…”