# 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

## TL;DR

This study in Abidjan, Côte d’Ivoire, shows that monitoring children's lung function and air pollution exposure is feasible, revealing high pollution levels and reduced lung function.

## Contribution

Demonstrates the feasibility of using portable devices to jointly monitor PM2.5 exposure and lung function in African children.

## Key findings

- Ambulatory monitoring of PM2.5 and spirometry is feasible in children using portable devices.
- Median PM2.5 concentrations were high at 164.2 µg/m³, with morning pollution peaks.
- Increased PM2.5 exposure was associated with a significant decrease in lung function within 2 hours.

## Abstract

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 (PM2.5)) and spirometry in children living in Abidjan, Côte d’Ivoire.

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 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 (ppFEV1), and hourly geometric mean PM2.5 concentrations, and analysed the cumulative delayed effects of PM2.5 on ppFEV1 using distributed lag non-linear models.

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 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; 6328 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 IQR increase of 120.9 µg/m³ in PM2.5 exposure (β=−2.21; CI −3.74 to −0.69).

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 on the respiratory effects of air pollution in children.