A large-scale personal monitoring of air pollution during pregnancy in the BiSC cohort

Abstract

Background and aim: Large-scale monitoring of personal exposure to air pollution remains scarce, especially for pregnant women. We present the results of one of the largest monitoring campaigns of personal, home-indoor, and home-outdoor air pollution on pregnant women. Methods: The Barcelona Life Study Cohort (BiSC) is an ongoing cohort of 1086 mother-child pairs in Barcelona, Spain (2018 onwards). We monitored personal exposure to particulate matter ≤ 2.5 µm (PM2.5; filter samples for chemical characterisation), Black Carbon (BC; MicroAeth AE51), and personal, home indoor and outdoor nitrogen dioxide (NO2; Gradko passive tubes) at first (week 12, w12) and third trimester (w32) of pregnancy. The Covid pandemic forced us to stop data collection on PM2.5 and BC. Results: Weekly averaged concentrations (for both w12 and w32) for NO2 were 28.5 ± 12.0, 24.2 ± 11.7, and 38.9 ± 15.8 µg/m3 for personal exposure (N = 1680), indoors (N = 1685) and outdoors (N = 1570), respectively. Personal 48h average concentration was 21.0 ± 15.7 µg/m3 for PM2.5 (N = 498) and 1.63 ± 0.78 µg/m3 for BC (N = 374). Compared to current WHO 24-h outdoor air quality guidelines, 55.5% of PM2.5 samples and 89 % (outdoor) and 58.6% (personal) NO2 samples were above the recommendations (15 and 25 µg/m3, respectively). Correlations were higher between personal and indoor NO2 (spearman coefficient, r, >0.74) than between personal and outdoor (r <0.42) in both w12 and w32, due to a larger time spent at home (indoors). Moderate correlations between indoor and outdoor NO2 may be explained by potential indoor sources and indoor consumption of NO2 in gas-phase reactions. Conclusions: BiSC is one of the largest studies on air pollution exposure measurements on pregnant women. Participants were exposed to a wide range of air pollutants’ concentrations. Keywords: Pregnant women, Personal exposure assessment, Air Pollution