Search

Ambient fine particulate matter (PM 2.5 ) is a leading environmental risk factor globally, and over half of the associated disease burden are caused by cardiovascular disease. Numerous randomized controlled trials (RCT) have investigated the short-term cardiovascular benefits of indoor air purifiers (IAPs), but major knowledge gaps remain on their longer-term benefits. In this 1-year, randomized, double-blinded, parallel controlled trial of 47 elderly (n true-purification  = 24; n sham-purification  = 23) aged ≥70 years, true-purification reduced household PM 2.5 levels by 28% and maintained lower exposure throughout the year compared to the sham-purification group. After 12 months of intervention, a significant reduction of diastolic blood pressure was found in the true-purification versus sham-purification group (-4.62 [95% CI: -7.28, -1.96] mmHg) compared to baseline measurement prior to the intervention, whereas systolic blood pressure showed directionally consistent but statistically non-significant effect (-2.49 [95% CI: -9.25, 4.28] mmHg). Qualitatively similar patterns of associations were observed for pulse pressure (-2.30 [95% CI: -6.57, 1.96] mmHg) and carotid intima-media thickness (-10.0% [95% CI: -24.8%, 4.7%]), but these were not statistically significant. Overall, we found suggestive evidence of cardiovascular benefits of long-term IAPs use, particularly on diastolic blood pressure. Evidence on other longer-term cardiovascular traits is less clear. Further trials with larger sample sizes and long-term follow-up are needed across diverse populations to evaluate the cardiovascular benefits of IAPs., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Ka Hung Chan reports financial support was provided by BHF Centre of Research Excellence. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Few studies have focused on the spatial distribution of the typical components and source tracers of PM 2.5 and their associated health risks, despite the fact that the chemical components of PM 2.5 pose potentially significant and independent risks to human health. The main objective of this study was to evaluate the spatial distribution of major PM 2.5 components and their associated health risks in Hong Kong using a coupled land use regression and health risk assessment modeling approach. The established land use regression models of the major PM 2.5 components and source tracers achieved a relatively high statistical performance, with training and leave-one-out cross-validation R 2 values of 0.85-0.96 and 0.62-0.88, respectively. The high spatial resolution (500 m × 500 m) distribution patterns of the chemical components of PM 2.5 showed the heterogeneity of population exposure to different components and the related potential health risks, as evidenced by the weak spatial correlations between the mass of PM 2.5 and some components. Elemental carbon, nickel, arsenic, and chromium from PM 2.5 made major contributions to the total health risk and should therefore be reduced further. Our results will enable researchers to determine independent associations between exposure to the various components of PM 2.5 and health endpoints in epidemiological studies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Patients with chronic obstructive pulmonary disease (COPD) often experience deteriorating gaseous exchange which in turn may result in declines in blood oxygen saturation (SpO 2 ). Increasing evidence has also shown that elevated levels of fine particulate matter (PM 2.5 ) may contribute to COPD pathogenesis. However, the acute effects of PM 2.5 on SpO 2 among COPD patients remain unclear, especially for its time course. Therefore, we conducted this panel study with 3-day real-time monitoring for personal PM 2.5 exposure and concurrent SpO 2 of 39 participants (20 COPD patients, 19 healthy participants), aged 60 to 90 years, in Hong Kong to explore the acute effects of personal PM 2.5 exposure on SpO 2 (within minutes to hours). We applied a linear mixed effect model to examine the associations between personal PM 2.5 and SpO 2 , while adjusting for temporal trend, personal characteristics, weather conditions, and co-exposure to gaseous pollutants (ambient ozone, nitrogen dioxides, carbon monoxide, and atmospheric pressure). We found that short-term exposure to PM 2.5 might result in acute declines of SpO 2 within minutes, and the effects would last for several hours. An interquartile range increase of personal PM 2.5 exposure (17.2 μg/m 3 ) was associated with -0.19% (95% CI: -0.26% to -0.12%) changes of concurrent SpO 2 for all participants. The most significant decline was observed at lag0-3 h, and then became insignificant at lag0-12 h. At lag0-1 h, estimated mean changes of SpO 2 were -0.40% (95% CI: -0.55% to -0.24%) for COPD patients and -0.09% (95% CI: -0.23% to 0.06%) for healthy participants. Compared with healthy participants, the effects of PM 2.5 exposure on SpO 2 for COPD patients were slightly stronger and more acute. Reducing PM 2.5 concentrations might be a useful approach to improve health status and reduce exacerbations for COPD patients., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Few studies have investigated the short-term effect of personal temperature exposure on blood oxygen saturation (SpO 2 ). We conducted this longitudinal panel study with real-time monitoring of SpO 2 and environmental exposure for 3 continuous days for 20 patients with chronic obstructive pulmonary disease (COPD) and 20 healthy volunteers in Hong Kong, to explore the time course (from minutes to hours) of change in SpO 2 in response to temperature in elderly people. We employed a generalized additive mixed model to evaluate the acute effects of personal temperature exposure on changes in SpO 2 and risk of oxygen desaturation while adjusting for seasonality, environmental co-exposures, and personal characteristics. We observed a concurrent decline in SpO 2 by 0.27% (95% confidence interval [CI]: 0.22-0.32%) and an increase in the risk of oxygen desaturation by an OR of 1.14 (95% CI, 1.10-1.18) associated with a 1 °C increase in personal temperature, and the association lasted over several hours. Results showed that the decline in SpO 2 in elderly people was associated with an increase in personal temperature exposure within minutes to hours, particularly in women and male patients with COPD. Temperature-induced oxygen desaturation may play a pivotal role in COPD exacerbation.