Arterial blood pressure responses to short-term exposure to fine and ultrafine particles from indoor sources - A randomized sham-controlled exposure study of healthy volunteers

•Our study suggests differential effects of indoor exposure on blood pressure depending on source and particle metric.•In contrast to particle exposure from toasting bread, frying sausages and burning candles showed no consistent association.•Differences in chemical composition of source-specific particles might account for these differential effects.•SBP increased most rapidly in association with the commonly used metrics PM10 and PM2.5.•Yet, the highest increase of SBP was observed 4 h after exposure for the metrics PNC and PSC.

ObjectivesParticulate air pollution is linked to adverse cardiovascular effects. The aim of the study was to investigate the effect of short-term exposure to indoor particles on blood pressure (BP).MethodsWe analyzed the association of particle emissions from indoor sources (candle burning, toasting bread, frying sausages) with BP changes in 54 healthy volunteers in a randomized cross-over controlled exposure study. Particle mass concentration (PMC), size-specific particle number concentration (PNC) and lung-deposited particle surface area concentration (PSC) were measured during the 2 h exposure. Systolic and diastolic blood pressure were measured before, during, directly, 2, 4 and 24 h after exposure. We performed multiple mixed linear regression analyses of different particle metrics and BP.ResultsBP significantly increased with increasing PMC, PSC and PNC resulting from toasting bread. For example, an increase per 10 µg/m3 PM10 and PM2.5, systolic BP increased at all time points with largest changes 1 h after exposure initiation of 1.5 mmHg (95%-CI: 1.1; 1.9) and of 2.2 mmHg (95%-CI: 1.3; 3.1), respectively.ConclusionsOur study suggests an association of short-term exposure to fine and ultrafine particles emitted from toasting bread with increases in BP. Particles emitted from frying sausages and candle burning did not consistently affect BP.