Ultrafine, fine, and black carbon particle concentrations in California child-care facilities

Abstract

Although many U.S. children spend time in child care, little information exists on exposures to airborne particulate matter (PM) in this environment, even though PM may be associated with asthma and other respiratory illness, which is a key concern for young children. To address this data gap, we measured ultrafine particles (UFP), PM 2.5 , PM 10 , and black carbon in 40 California child-care facilities and examined associations with potential determinants. We also tested a low-cost optical particle measuring device (Dylos monitor). Median (interquartile range) concentrations for indoor UFP, gravimetric PM 2.5 , real-time PM 2.5 , gravimetric PM 10 , and black carbon over the course of a child-care day were 14 000 (11 000-29 000) particles/cm Dylos may be a valid low-cost alternative to monitor PM levels indoors in future studies. Overall, results indicate the need for additional studies examining particle levels, potential health risks, and mitigation strategies in child-care facilities. K E Y W O R D Sdaycare, early childhood education, indoor air, predictors matter (PM) in child-care facilities, despite children being more susceptible than adults to the health effects of PM exposures. | INTRODUCTION 9-11Particulate matter is a complex mixture of small particles and liquid droplets. Constituents include inorganic compounds (such as nitrates and sulfates), organic chemicals, metals, and soil or dust particles.Exposures of young children to PM 2.5 (particles with an aerodynamic diameter ≤2.5 μm) and PM 10 (aerodynamic diameter ≤10 μm) have been shown to increase allergen sensitization, decrease lung function, and exacerbate pre-existing respiratory conditions like asthma. 12-15Ultrafine particle (UFP, aerodynamic diameter <0.1 μm) exposure to young children has been associated with decreased lung function 16 and increased risk of respiratory hospital admissions. [12][13][14][15]17,18 In children, black carbon exposure has been associated with lung oxidative stress, 19-21 decreased lung function, 22 and respiratory symptoms. 23-25

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

“…Regarding levels found in schools (Figure ), Buonanno et al and Morawska et al observed the highest concentrations (ranges of 1.95‐3.49·10 4 part/cm 3 and 10.70‐14.00.10 4 part/cm 3 ), respectively, depending on the location of the school; values were higher in trafficked areas than in rural zones and also higher outdoors than indoors. Fonseca et al, both of the studies by Rufo et al and Slezakova et al measured concentrations of between 1.15 and 1.82·10 4 part/cm 3 inside Portuguese schools, which are values that are similar to the measurements of both studies conducted in Greece (between 0.5 and 2.5.10 4 part/cm 3 , and 2.4·10 4 part/cm 3 , respectively) and those found in Australia, Spain, Italy, California, and Seoul, between 0.8·10 4 part/cm 3 and 1.8·10 4 part/cm 3 . Mullen et al, Rufo et al, Weichental et al and Zhang and Zhu quantified the lowest concentrations (between 0.1 and 0.7·10 4 part/cm 3 ).…”

“…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 …”

“…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.…”

“…Schools were the most studied microenvironments. Eight studies analyzed schools with different traffic conditions nearby (urban area, rural area, next to a motorway, etc), and others focused more on the levels in different rooms and places in the schools . Only three studies measured levels in houses .…”

“…Other models were also used in some cases. For example, Gaspar et al, Mazaheri et al and Mullen et al used the model 3781 (detection limit 5‐2500 nm); Buonanno et al used the model 3775 (detection limit 4‐3000 nm); both studies by Zhang and Zhu used the model 3785 (detection limit 5‐1000 nm); Morawska et al used the model 3022 (detection limit 7‐3000 nm); and both studies by Diapouli et al used the model 3007 (detection limit 10‐1000 nm).…”