Feasibility and results of joint ambulatory monitoring of exposure to particulate matter pollution and lung function in children in Abidjan, Côte d Ivoire, a cross-sectional observational study.

Background Children are largely exposed to air pollution in low- and-middle income countries, yet data on exposure and respiratory effects of air pollution remain limited. This study aimed to assessed the feasibility and outcomes of joint ambulatory monitoring of exposure to fine particulate matter (PM2.5) and spirometry in children living in Abidjan, Côte d Ivoire. Methods We did a cross-sectional observational study among children aged 7-17 years. After a baseline spirometry, children were asked to wear portable PM2.5 sensors and to perform 2X3 daily flow-volume curves using a portable spirometer for 7 days. We described the proportion of acceptable measurements, percent predicted forced expiratory volume (ppFEV1), and hourly geometric mean PM2.5 concentrations, and analyzed the cumulative delayed effects of PM2.5 on ppFEV1 using distributed lag non-linear models (DLNMs). Results Of 29 children enrolled - 18 (62.1%) female, median age 12 years - all performed spirometry with 1101 (90.4%) of 1218 expected flow-volume curves obtained; 313 (28.4%) valid non-duplicate curves were analyzed. The median ppFEV1 was 79.6% 71.5-87.4; with lower values in the morning than in the evening (p < 0.001). Of 146,160 expected PM2.5 measurements, 93,689 (64.1%) were obtained; 6,328 aberrant data were excluded. The median hourly PM2.5 concentrations were 164.2 107.0 - 272.2 μg/m3. PM2.5 levels varied throughout the day with pollution peaks observed in the morning. A significant decrease in ppFEV1; was observed between 0 and 2 hours post-exposure, after an interquartile range increase of 120.9 μg/m3 in PM2.5 exposure (β = -2.21; CI -3.74; -0.69). Conclusion Ambulatory spirometry and PM2.5 measurements are feasible with portable devices in African children. High PM2.5 exposure and individual variability in lung function highlight the need for further research respiratory effects of air pollution in children.