Personal exposure to particulate matter and heart rate variability among informal electronic waste workers at...

Informal electronic waste recycling activities are major contributors to ambient air pollution, yet studies assessing the effects or relationship between direct/continuous exposure of informal e-waste workers to particulate matter and cardiovascular function are rare.

Repeated measurements of fractions of PM_2.5, PM_10-2.5, and PM₁₀ in personal air of informal e-waste workers, (n = 142) and a comparable group (n = 65) were taken over a period of 20 months (March 2017 to November, 2018). Concurrently, 5-min resting electrocardiogram was performed on each participant to assess resting heart rate variability indices. Linear mixed-effects models were used to assess the association between PM fractions and cardiac function.

SDNN, RMSSD, LF, HF and LH/HF ratio were all associated with PM. Significant associations were observed for PM_2.5 and Mean NN (p = 0.039), PM10 and SDNN (p = 0.035) and PM 10-2.5 and LH/HF (p = 0.039). A 10 μg/m³ increase in the concentrations of PM _2.5, PM_10-2.5, and PM₁₀ in personal air was associated with reduced HRV indices and increased resting HR. A 10 μg/m³ per interquartile (IQR) increase in PM_10-2.5 and PM₁₀, decreased SDNN by 11% [(95% CI: - 0.002- 0.000); (p = 0.187)] and 34% [(95% CI: - 0.002-0.001); (p = 0.035)] respectively. However, PM_2.5 increased SDNN by 34% (95% CI: - 1.32-0.64); (p = 0.493). Also, 10 μg/m³ increase in PM_2.5, PM_10-2.5 and PM₁₀ decreased RMSSD by 27% [(- 1.34-0.79); (p = 0.620)], 11% [(- 1.73, 0.95); (p = 0.846)] and 0.57% [(- 1.56-0.46); (p = 0.255%)].

Informal e-waste workers are at increased risk of developing cardiovascular disease from cardiac autonomic dysfunction as seen in reduced HRV and increased heart rate.