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. Author manuscript; available in PMC: 2024 May 1.
Published in final edited form as: Paediatr Perinat Epidemiol. 2023 Feb 13;37(5):436–444. doi: 10.1111/ppe.12960

TABLE 2.

Descriptive statistics of hourly and daily exposure to air pollutants as measured by Flow personal air monitor in pregnant women.

Hourly average
 Daily average
Mean (SD) Median (25th, 75th) Mean (SD) Median (25th, 75th)
NO2, ppb 13.5 (13.3) 9.6 (3.6, 19.2) 9.8 (8.4) 7.6 (4.0, 13.3)
PM1, μ/m3 3.1 (6.5) 1.1 (1.0, 1.95) 2.7 (5.1) 1.2 (1.0, 2.0)
PM2.5, μ/m3 5.7 (8.6) 2.4 (2.0, 5.0) 5.0 (6.8) 2.6 (2.2, 4.7)
VOC, ppb 185.4 (117.1) 162.3 (139.1, 193.1) 173.4 (73.2) 163.9 (147.3, 184.0)

Note: Data were from 3827 days of air monitoring in 273 participants between November 2019 and May 2022 in New York City.

Hourly averages were calculated using the geometric mean of minute-by-minute data, after data truncation at 99th percentile. Daily averages were calculated using the arithmetic mean of hourly averages.

Abbreviations: NO2, nitrogen dioxide; PM1, particulate matter with aerodynamic diameter <1 μm; PM2.5, particulate matter with aerodynamic diameter <2.5 μm; SD, standard deviation; VOC, volatile organic compounds.