Quantifying personal exposure to traffic and household air pollution: a pilot study among street traders in Lagos, Nigeria.

BACKGROUND

Ambient and household air pollution (HAP) exposure is associated with adverse health outcomes. Heavy traffic congestion, street trading, and the use of biomass fuels are common in Lagos, Nigeria. We designed this study to evaluate the feasibility of measuring prolonged personal exposure to air pollution among street traders. We aimed to quantify average 24-hour exposure to air pollution and evaluate how proximity to major highways influences these levels.

METHODS

We conducted a cross-sectional study assessing recruitment and level of personal exposure to traffic-related air pollution (TRAP) and HAP among adult street traders over 48 hours. We recruited 'highway traders' (<50 m of the highway) and 'inner street traders' (>200 m from the highway) and measured personal exposure to particulate matter (PM2.5 and PM10) using a bespoke monitoring unit held in a backpack. We also measured blood pressure (BP) and performed spirometry.

RESULTS

The recruitment rate was 33%, yielding a sample of 30 females (15 per group). All eligible males declined due to time constraints and because they found the backpack monitor unacceptable. The average 24-hour PM2.5 (mean (x̄) = 34.3 μg/m3) and PM10 (x̄ = 34.7 μg/m3) exposures for highway traders were higher than PM2.5 (x̄ = 22.8 μg/m3) and PM10 (x̄ = 23.0 μg/m3) exposures for inner street traders. The PM2.5 over 24 hours was consistently above the World Health Organization recommended threshold of 15ug/m3 for both groups with diurnal peaks. Spirometry parameters and BP were similar between the two groups.

CONCLUSIONS

Device acceptability and measurement site selection are pivotal in participant recruitment. Successful gender-inclusive recruitment necessitates appropriate monitoring equipment and measurement at sites convenient for participants. All street traders experienced consistently high air pollution levels throughout the day, regardless of proximity to the highway. These findings provide valuable insights to guide future large-scale research.