Reducing Personal Exposure to Particulate Air Pollution Improves Cardiovascular Health in Patients with Coronary Heart Disease

Abstract

Background: Air pollution exposure increases cardiovascular morbidity and mortality and is a major global public health concern.Objectives: We investigated the benefits of reducing personal exposure to urban air pollution in patients with coronary heart disease.Methods: In an open randomized crossover trial, 98 patients with coronary heart disease walked on a predefined route in central Beijing, China, under different conditions: once while using a highly efficient face mask, and once while not using the mask. Symptoms, exercise, personal air pollution exposure, blood pressure, heart rate, and 12-lead electrocardiography were monitored throughout the 24-hr study period.Results: Ambient air pollutants were dominated by fine and ultrafine particulate matter (PM) that was present at high levels [74 μg/m3 for PM2.5 (PM with aerodynamic diamater <2.5 µm)]. Consistent with traffic-derived sources, this PM contained organic carbon and polycyclic aromatic hydrocarbons and was highly oxidizing, generating large amounts of free radicals. The face mask was well tolerated, and its use was associated with decreased self-reported symptoms and reduced maximal ST segment depression (–142 vs. –156 μV, p = 0.046) over the 24-hr period. When the face mask was used during the prescribed walk, mean arterial pressure was lower (93 ± 10 vs. 96 ± 10 mmHg, p = 0.025) and heart rate variability increased (high-frequency power: 54 vs. 40 msec2, p = 0.005; high-frequency normalized power: 23.5 vs. 20.5 msec, p = 0.001; root mean square successive differences: 16.7 vs. 14.8 msec, p = 0.007). However, mask use did not appear to influence heart rate or energy expenditure.Conclusions: Reducing personal exposure to air pollution using a highly efficient face mask appeared to reduce symptoms and improve a range of cardiovascular health measures in patients with coronary heart disease. Such interventions to reduce personal exposure to PM air pollution have the potential to reduce the incidence of cardiovascular events in this highly susceptible population.

A rapid assessment of the impact of hazard reduction burning around Sydney, May 2016

“…Interesting evidence comes from experimental studies that look at the health effects of trafficgenerated air pollution: volunteers may have been asked to cycle, walk, or sit at a bus stop in the midst of busy traffic (Langrish et al, 2012;McCreanor et al, 2007;Weichenthal et al, 2011). The studies suggest that 1-2 hours of exposure may be enough to lead to harmful physiological changes.…”

Experimental Human Exposure to Air Pollutants Is Essential to Understand Adverse Health Effects

“…In this regard, quasi-experimental studies on nonsmoking medical residents and healthy adults before, during, and after the Beijing Olympics demonstrated lower air pollutants during the Olympics that correlated with reduced pulmonary inflammation and oxidative stress (40,41). An intervention using a highly efficient facemask used by 100 patients with coronary heart disease on Beijing streets showed reduced personal exposure to fine particulate that correlated with reduced symptoms and electrocardiographic ST segment depression (42). The remarkable record of safety of studies of controlled chamber and "real world" exposures is at least partially attributable to the intimate involvement of IRBs in reviewing protocols in detail, checking the wording of the informed consent, the mechanisms for recruitment, conducting audits, and mandating data safety monitoring plans for continuous ongoing survey of expected and unexpected adverse events.…”

Road Repairs

“…These factors influence not only total exposure, but also exposure to specific pollutants and the dose rate of exposure. Subsequent studies could consider personal exposure to PM through the use of portable PM monitoring devices 23,24 that are evolving to provide greater reliability, better stratification of particle size distributions, and sampling of particulates for toxicological studies. Ultimately, controlled human exposure studies and experimental studies are necessary to demonstrate causality and to understand the functional consequences of exposure on circulating progenitor cells.…”