Research

Beneficial cardiovascular effects of reducing exposure to particulate air pollution with a simple facemask

Jeremy P Langrish¹ , Nicholas L Mills¹ , Julian KK Chan¹ , Daan LAC Leseman² , Robert J Aitken³ , Paul HB Fokkens² , Flemming R Cassee² , Jing Li⁴ , Ken Donaldson¹ , David E Newby¹ and Lixin Jiang⁴

¹  Centre for Cardiovascular Sciences, Edinburgh University, Edinburgh, UK

²  Centre for Environmental Health, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands

³  Institute of Occupational Medicine, Edinburgh, UK

⁴  Fuwai Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, PR China

author email corresponding author email

Particle and Fibre Toxicology 2009, 6:8doi:10.1186/1743-8977-6-8

Published:	13 March 2009

Abstract

Background

Exposure to air pollution is an important risk factor for cardiovascular morbidity and mortality, and is associated with increased blood pressure, reduced heart rate variability, endothelial dysfunction and myocardial ischaemia. Our objectives were to assess the cardiovascular effects of reducing air pollution exposure by wearing a facemask.

Methods

In an open-label cross-over randomised controlled trial, 15 healthy volunteers (median age 28 years) walked on a predefined city centre route in Beijing in the presence and absence of a highly efficient facemask. Personal exposure to ambient air pollution and exercise was assessed continuously using portable real-time monitors and global positional system tracking respectively. Cardiovascular effects were assessed by continuous 12-lead electrocardiographic and ambulatory blood pressure monitoring.

Results

Ambient exposure (PM_2.5 86 ± 61 vs 140 ± 113 μg/m³; particle number 2.4 ± 0.4 vs 2.3 ± 0.4 × 10⁴ particles/cm³), temperature (29 ± 1 vs 28 ± 3°C) and relative humidity (63 ± 10 vs 64 ± 19%) were similar (P > 0.05 for all) on both study days. During the 2-hour city walk, systolic blood pressure was lower (114 ± 10 vs 121 ± 11 mmHg, P < 0.01) when subjects wore a facemask, although heart rate was similar (91 ± 11 vs 88 ± 11/min; P > 0.05). Over the 24-hour period heart rate variability increased (SDNN 65.6 ± 11.5 vs 61.2 ± 11.4 ms, P < 0.05; LF-power 919 ± 352 vs 816 ± 340 ms², P < 0.05) when subjects wore the facemask.

Conclusion

Wearing a facemask appears to abrogate the adverse effects of air pollution on blood pressure and heart rate variability. This simple intervention has the potential to protect susceptible individuals and prevent cardiovascular events in cities with high concentrations of ambient air pollution.