Cardiopulmonary Benefits of Reducing Indoor Particles of Outdoor Origin

Abstract

Background Indoor exposure to fine particulate matter (PM2.5) from outdoor sources is a major health concern, especially in highly polluted developing countries, such as China. Few studies have evaluated the effectiveness of indoor air purification on the improvement of cardiopulmonary health in these areas. Objectives To evaluate whether a short-term indoor air purifier intervention improves cardiopulmonary health. Methods We conducted a randomized double-blind crossover trial among 35 healthy college students in Shanghai, China in 2014. These students lived in dormitories that were randomized into 2 groups and alternated the use of true or sham air purifiers for 48 h with a 2-week washout interval. We measured 14 circulating biomarkers of inflammation, coagulation and vasoconstriction, lung function, blood pressure (BP), and fractional exhaled nitric oxide (FeNO). We applied linear mixed-effect models to evaluate the effect of the intervention on health outcome variables. Results On average, air purification resulted in a 57% reduction in PM2.5 concentration from 96.2 to 41.3 μg/m3 within hours of operation. Air purification was significantly associated with decreases in geometric means of several circulating inflammatory and thrombogenic biomarkers, including 17.5% in monocyte chemoattractant protein-1, 68.1% in interleukin-1β, 32.8% in myeloperoxidase and 64.9% in soluble CD40 ligand. Further, systolic BP, diastolic BP, and FeNO were significantly decreased by 2.7%, 4.8%, and 17.0% in geometric mean, respectively. The impacts on lung function and vasoconstriction biomarkers were beneficial, but not statistically significant. Conclusion This intervention study demonstrated clear cardiopulmonary benefits of indoor air purification among young, healthy adults in a Chinese city with severe ambient particulate air pollution. (Intervention Study on the Health Impact of Air Filters in Chinese Adults; NCT02239744)

Particulate Matter Exposure and Stress Hormone Levels

“…In this randomized, double-blind, crossover trial, we found marked changes in serum metabolites, including hormones, glucose, amino acids, and lipids, in association with higher PM 2.5 exposure. Consistent with previous publications from us 29 and other groups in China, 7,30 we also observed increases in blood pressure and levels of biomarkers of inflammation and oxidative stress in relation to higher PM 2.5 .…”

“…In this randomized, double-blind, crossover trial, we found marked changes in serum metabolites, including hormones, glucose, amino acids, and lipids, in association with higher PM 2.5 exposure. Consistent with previous publications from us 29 and other groups in China, 7,30 we also observed increases in blood pressure and levels of biomarkers of inflammation and oxidative stress in relation to higher PM 2.5 .Results from this clinical trial suggest that the human central nervous system reacts to changes in PM exposures. We observed increases in glucocorticoids, ACTH, and CRH in relation to higher PM exposure, suggesting activation of the hypothalamus-pituitary-adrenal (HPA) axis.…”

“…These observations are consistent with some but not all the previous studies. 15,29,[32][33][34] In addition to its physiological effects on blood pressure, glucocorticoids may also affect energy metabolism by increasing metabolic rate and energy expenditure, increasing blood glucose levels, and enhancing lipolysis, lipid oxidation, proteolysis, and insulin resistance. [35][36][37][38][39] In the present study, we also consistently found that higher PM 2.5 exposure was ORIGINAL RESEARCH ARTICLE associated with increased levels of homeostatic model assessment of insulin resistance, glucose, fatty acids, acylcarnitines, and amino acids.…”

“…It builds on a previous study from us that demonstrated clear cardiopulmonary benefits following 48 hours of consecutive indoor air purification among college students. 29 Although it remains to be examined whether the observed health benefits could be generalized to other populations or be translated to long-term health benefits, this study offers a very practical way to mitigate some of the adverse health effects for residents in areas with relatively high air pollution.…”

Short‐Term Exposure to Fine Particulate Matter Air Pollution Is Preferentially Associated With the Risk of ST‐Segment Elevation Acute Coronary Events

“…In fact, there is evidence that adverse mechanisms associated with PM 2.5 exposure include elevated inflammation and enhanced thrombosis as well as vascular dysfunction and autonomic imbalance 1, 2. A recent randomized, double‐blind, crossover intervention study of healthy adults from Shanghai, China, for example, reported that substantial reductions in PM 2.5 exposures for 48 hours from air purification resulted in cardiopulmonary benefits, including decreases in several circulating inflammatory and thrombogenic biomarkers and lower systolic and diastolic blood pressure 27. Given these implied adverse mechanisms, in the context of universal definition and clinical classification of MI,28 these results suggest that there are differential effects of PM 2.5 exposures on different types of MI.…”