title: Concentrations and Sources of Airborne Particles in a Neonatal Intensive Care Unit.
abstract: Premature infants in neonatal intensive care units (NICUs) have underdeveloped immune systems, making them susceptible to adverse health consequences from air pollutant exposure. Little is known about the sources of indoor airborne particles that contribute to the exposure of premature infants in the NICU environment. In this study, we monitored the spatial and temporal variations of airborne particulate matter concentrations along with other indoor environmental parameters and human occupancy. The experiments were conducted over one year in a private-style NICU. The NICU was served by a central heating, ventilation and air-conditioning (HVAC) system equipped with an economizer and a high-efficiency particle filtration system. The following parameters were measured continuously during weekdays with 1-min resolution: particles larger than 0.3 μm resolved into 6 size groups, CO2 level, dry-bulb temperature and relative humidity, and presence or absence of occupants. Altogether, over sixteen periods of a few weeks each, measurements were conducted in rooms occupied with premature infants. In parallel, a second monitoring station was operated in a nearby hallway or at the local nurses' station. The monitoring data suggest a strong link between indoor particle concentrations and human occupancy. Detected particle peaks from occupancy were clearly discernible among larger particles and imperceptible for submicron (0.3-1 μm) particles. The mean indoor particle mass concentrations averaged across the size range 0.3-10 μm during occupied periods was 1.9 μg/m(3), approximately 2.5 times the concentration during unoccupied periods (0.8 μg/m(3)). Contributions of within-room emissions to total PM10 mass in the baby rooms averaged 37-81%. Near-room indoor emissions and outdoor sources contributed 18-59% and 1-5%, respectively. Airborne particle levels in the size range 1-10 μm showed strong dependence on human activities, indicating the importance of indoor-generated particles for infant's exposure to airborne particulate matter in the NICU.
authors.affiliation: Department of Civil and Environmental Engineering, University of California, Berkeley, California, United States of America.
authors.forename: Dusan
authors.initials: D
authors.lastname: Licina
authors.affiliation: Department of Civil and Environmental Engineering, University of California, Berkeley, California, United States of America.
authors.forename: Seema
authors.initials: S
authors.lastname: Bhangar
authors.affiliation: Department of Earth and Planetary Sciences, University of California, Berkeley, California, United States of America.
authors.forename: Brandon
authors.initials: B
authors.lastname: Brooks
authors.affiliation: Division of Newborn Medicine, Magee-Womens Hospital of UPMC, Pittsburgh, Pennsylvania, United States of America.
authors.forename: Robyn
authors.initials: R
authors.lastname: Baker
authors.affiliation: Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America.
authors.forename: Brian
authors.initials: B
authors.lastname: Firek
authors.affiliation: Department of Civil and Environmental Engineering, University of California, Berkeley, California, United States of America.
authors.forename: Xiaochen
authors.initials: X
authors.lastname: Tang
authors.affiliation: Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America.|Division of Pediatric Surgery, Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, United States of America.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Morowitz
authors.affiliation: Department of Earth and Planetary Sciences, University of California, Berkeley, California, United States of America.
authors.forename: Jillian F
authors.initials: JF
authors.lastname: Banfield
authors.affiliation: Department of Civil and Environmental Engineering, University of California, Berkeley, California, United States of America.
authors.forename: William W
authors.initials: WW
authors.lastname: Nazaroff
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D016902:Air Pollution, Indoor / Q000032:analysis*; D002245:Carbon Dioxide / Q000032:analysis; D006801:Humans; D007363:Intensive Care Units, Neonatal; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis*; D013223:Statistics as Topic; D013997:Time Factors
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D002245:Carbon Dioxide