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 assess the feasibility and outcomes of joint ambulatory monitoring of exposure to fine particulate matter (particles with a diameter of less than 2.5 µm (PM 2.5 )) 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 PM 2.5 sensors and to perform 2×3 daily flow–volume curves using a portable spirometer for 7 days. We described the proportion of acceptable measurements, per cent predicted forced expiratory volume (ppFEV 1 ), and hourly geometric mean PM 2.5 concentrations, and analysed the cumulative delayed effects of PM 2.5 on ppFEV 1 using distributed lag non-linear models. Results Of 29 children enrolled, 18 (62.1%) were female, median age 12 years, all performed spirometry with 1101 (90.4%) of 1218 expected flow-volume curves obtained. Of these, 625 (51.3%) acceptable curves were received and 313 valid, non-duplicate curves were analysed. The median ppFEV 1 was 79.6% (71.5–87.4), with lower values in the morning than in the evening (p