Acute Blood Pressure and Cardiovascular Effects of Near-Roadway Exposures With and Without N95 Respirators

Interventions to reduce the impact of outdoor air pollution on asthma: A systematic review

Background

Exposure to air pollution can cause adverse health effects in people living with chronic lung disease. In people with asthma, it is not clear whether strategies to reduce outdoor air pollution can affect clinical symptoms and lung function.

Objectives

To determine strategies to reduce air pollution exposure for people with asthma, and to describe the effect of reduced air pollution on asthma outcome.

Methods

A systematic review was conducted of six databases for English literature. Any study published between April 2012 and March 2022 that mentioned air pollution exposure reduction and asthma was reviewed. Two reviewers (STH and RMp) screened and extracted the data separately, using a standardised form based on the Cochrane data extraction tool. Risk of bias was assessed using the risk-of bias 2 tool. Outcome measures were the Asthma Control Test (ACT), the Childhood Asthma Control Test, exacerbations, and the forced expiratory volume in the 1st second (FEV1 ), forced vital capacity (FVC) and FEV1 /FVC ratio. The study was registered with PROSPERO (reg. no. CRD42022341648).

Results

Of the 11 116 identified studies, eight met the inclusion criteria, with a total of 11 395 043 participants. Clean air policy implementation modestly improved lung function, as shown by an increase in FVC and FEV1 of 0.02 L/year and 0.01 L/year, respectively. Reduction of exposure to outdoor smoke pollution with use of mobile application alerts resulted in behavioural change and improved ACT scores over 8 weeks (mean (standard deviation (SD)) 21.5 (2.3) compared with baseline (20.0 (2.4); p<0.001). Asthma control improved during low levels of pollution related to COVID-19 lockdown, as shown by mean (SD) ACT scores (17.3 (4.7) v. 19.7 (4.5); p<0.001) and associated declines in mean daily hospital admissions (4.5 (3.4) days v. 2.8 (2.5) days; p<0.001).

Conclusion

Air pollution is a major hazard, and strategies to reduce exposure have a positive outcome in terms of the asthma morbidity. This field would benefit from further high-quality randomised clinical trial evidence to inform policy and decision-making.

Study synopsis

What the study adds. The prevalence and burden of asthma are increasing globally. Air pollution exposure is a major cause of worse asthma symptoms. Strategies to reduce air pollution or exposure to it may contribute towards improved quality of life. This study highlights potential strategies and their effect on asthma outcome.Implications of the findings. A combination of individual activities and actions by governments to reduce air pollution can improve asthma outcome. A focus on education together with behavioural changes can reduce exposure at the individual level. Implementation of clean air policies reduces air pollution exposure and improves lung health.

[Air pollution, noise and hypertension : Partners in crime]

Air pollution and traffic noise are two important environmental risk factors that endanger health in urban societies and often act together as "partners in crime". Although air pollution and noise often co-occur in urban environments, they have typically been studied separately, with numerous studies documenting consistent effects of individual exposure on blood pressure. In the following review article, we examine the epidemiology of air pollution and noise, especially regarding the cardiovascular risk factor arterial hypertension and the underlying pathophysiology. Both environmental stressors have been shown to lead to endothelial dysfunction, oxidative stress, pronounced vascular inflammation, disruption of circadian rhythms and activation of the autonomic nervous system, all of which promote the development of hypertension and cardiovascular diseases. From a societal and political perspective, there is an urgent need to point out the potential dangers of air pollution and traffic noise in the American Heart Association (AHA)/American College of Cardiology (ACC) prevention guidelines and the European Society of Cardiology (ESC) guidelines on prevention. Therefore, an essential goal for the future is to raise awareness of environmental risk factors as important and, in particular, preventable risk factors for cardiovascular diseases.

Geo-Demographic and Socioeconomic Determinants of Diagnosed Hypertension among Urban Dwellers in Ibadan, Nigeria: A Community-based Study

Background

The relationship between diagnosed high blood pressure (HBP) and proximity to health facilities and noise sources is poorly understood. We investigated the relationship between proximity to noise sources, sociodemographic and economic factors, and diagnosed HBP in Ibadan, Nigeria.

Methods

We investigated 13,531 adults from the African Rigorous Innovative Stroke Epidemiological Surveillance (ARISES) study in Ibadan. Using a Geographic Information System (GIS), the locations of healthcare facilities, pharmaceutical shops, bus stops, churches, and mosques were buffered at 100m intervals, and coordinates of persons diagnosed with HBP were overlaid on the buffered features. The number of persons with diagnosed HBP living at every 100m interval was estimated. Gender, occupation, marital status, educational status, type of housing, age, and income were used as predictor variables. Analysis was conducted using Spearman rank correlation and binary logistic regression at p<0.05.

Results

There was a significant inverse relationship between the number of persons diagnosed with HBP and distance from pharmaceutical shops (r=-0.818), churches (r=-0.818), mosques (r=-0.893) and major roads (r=-0.667). The odds of diagnosed HBP were higher among the unemployed (AOR=1.58, 95% CI: 1.11-2.24), currently married (AOR=1.45, CI: 1.11-1.89), and previously married (1.75, CI: 1.29-2.38). The odds of diagnosed HBP increased with educational level and age group.

Conclusion

Proximity to noise sources, being unemployed and educational level were associated with diagnosed HBP. Reduction in noise generation, transmission, and exposure could reduce the burden of hypertension in urban settings.

Traffic Density Exposure, Oxidative Stress Biomarkers and Plasma Metabolomics in a Population-Based Sample: The Hortega Study

Exposure to traffic-related air pollution (TRAP) generates oxidative stress, with downstream effects at the metabolic level. Human studies of traffic density and metabolomic markers, however, are rare. The main objective of this study was to evaluate the cross-sectional association between traffic density in the street of residence with oxidative stress and metabolomic profiles measured in a population-based sample from Spain. We also explored in silico the potential biological implications of the findings. Secondarily, we assessed the contribution of oxidative stress to the association between exposure to traffic density and variation in plasma metabolite levels. Traffic density was defined as the average daily traffic volume over an entire year within a buffer of 50 m around the participants' residence. Plasma metabolomic profiles and urine oxidative stress biomarkers were measured in samples from 1181 Hortega Study participants by nuclear magnetic resonance spectroscopy and high-performance liquid chromatography, respectively. Traffic density was associated with 7 (out of 49) plasma metabolites, including amino acids, fatty acids, products of bacterial and energy metabolism and fluid balance metabolites. Regarding urine oxidative stress biomarkers, traffic associations were positive for GSSG/GSH% and negative for MDA. A total of 12 KEGG pathways were linked to traffic-related metabolites. In a protein network from genes included in over-represented pathways and 63 redox-related candidate genes, we observed relevant proteins from the glutathione cycle. GSSG/GSH% and MDA accounted for 14.6% and 12.2% of changes in isobutyrate and the CH2CH2CO fatty acid moiety, respectively, which is attributable to traffic exposure. At the population level, exposure to traffic density was associated with specific urine oxidative stress and plasma metabolites. Although our results support a role of oxidative stress as a biological intermediary of traffic-related metabolic alterations, with potential implications for the co-bacterial and lipid metabolism, additional mechanistic and prospective studies are needed to confirm our findings.

Particulate Air Pollution and Blood Pressure: Signaling by the Arachidonate Metabolism

BACKGROUND

Short-term exposure to ambient particulate matter (PM) can raise blood pressure, but the underlying mechanisms are unclear. We explored whether arachidonate metabolites serve as biological intermediates in PM-associated prohypertensive changes.

METHODS

This panel study recruited 110 adults aged 50 to 65 years living in Beijing, China. The participants' blood pressure, arterial stiffness, and cardiac and endothelial function were measured up to 7 times. The serum concentrations of arachidonate metabolites were quantified by targeted lipidomics. Ambient concentrations of fine PM (PM2.5), black carbon, and accumulation mode particles were continuously monitored at a station and their associations with the health indicators were evaluated.

RESULTS

Interquartile range increases in 25 to 96-hour-lag exposure to PM2.5, black carbon, and accumulation mode particles were associated with significant increases in systolic blood pressure (brachial: 0.8-3.2 mm Hg; central: 0.7-2.8 mm Hg) and diastolic blood pressure (brachial, 0.5-1.5 mm Hg; central, 0.5-1.6 mm Hg). At least 1 pollutant was associated with increases in augmentation pressure and heart rate and decreases in reactive hyperemia index and ejection time. The serum concentrations of arachidonate were significantly increased by 3.3% to 14.6% in association with PM exposure, which mediated 9% of the PM-associated increases in blood pressure. The levels of eicosanoids from the cytochrome P450, cyclooxygenase, and lipoxygenase pathways changed with PM exposure, and those from the cytochrome pathway significantly mediated the association between PM exposure and blood pressure.

CONCLUSIONS

Short-term exposure to particulate air pollution was associated with a prohypertensive change in adults, which was in part mediated by alteration of arachidonate metabolism.

Can individual protective measures safeguard cardiopulmonary health from air pollution? A systematic review and meta-analysis

Evidence supporting the effect of individual protective measures (IPMs) on air pollution is relatively scarce. In this study, we performed a systematic review and meta-analysis to investigate the effects of air purifiers, air-purifying respirators, and cookstove changes on cardiopulmonary health outcomes. We searched PubMed, Scopus, and Web of Science until December 31, 2022, 90 articles and 39,760 participants were included. Two authors independently searched and selected the studies, extracted information, and assessed each study's quality and risk of bias. We performed meta-analyses when three or more studies were available for each IPMs, with comparable intervention and health outcome. Systematic review showed that IPMs were beneficial in children and elderly with asthma along with healthy individuals. Meta-analysis results showed a reduction in cardiopulmonary inflammation using air purifiers than in control groups (with sham/no filter) with a decrease in interleukin 6 by -0.247 μg/mL (95% confidence intervals [CI] = -0.413, -0.082). A sub-group analysis for air purifier as an IPMs in developing counties reduced fractional exhaled nitric oxide by -0.208 ppb (95% confidence intervals [CI] = -0.394, -0.022). However, evidence describing the effects of air purifying respirator and cook stove changes on cardiopulmonary outcomes remained insufficient. Therefore, air purifiers can serve as efficient IPMs against air pollution. The beneficial effect of air purifiers is likely to have a greater effect in developing countries than in developed countries.

Urban workers' cardiovascular health due to exposure to traffic-originated PM2.5 and noise pollution in different microenvironments

The cardiovascular health of the people in urbanised cities is linked to traffic air, and noise pollution. This study investigated the cardiovascular health of people working in two microenvironments such as street (vendors) and workplace (office workers) whose blood pressure (BP) and heart rate (HR) might be affected due to regular exposure to PM_2.5 and traffic noise. The PM_2.5 and noise levels measurements, face-to-face questionnaire survey and health check-ups were carried out on working days from 10 A.M. to 8 P.M. in Jan-Dec 2019. The data was analysed by various statistical approaches in which the link between the traffic-borne PM_2.5 and noise level at 1/3rd octave frequencies has been established with the participants' BP and HR considering the demographic, socio-contextual, habitual and annoyance perception factors. The median measure of PM_2.5 and noise levels violated the WHO and NAAQS limits, i.e. 106.67 μg/m³ at street level and 33.33 μg/m³ at office indoor; and 71.35 dB (A) at the street and 65.78 dB (A) at office indoor. The results further showed that the workers working in traffic corridors had abnormally high BP and HR. The systolic BP, diastolic BP and HR values were higher than normal in male workers than female workers. The influence of low noise spectrum (50-630 Hz) was mostly observed. Therefore, the combined effect of PM_2.5 > 50 μg/m³ and noise spectrum (63 and 100 Hz) > 30 dB (A) significantly affect office workers' health in traffic corridors. The hearing aids, breathing troubles in the traffic corridor and annoyance perception also influenced the BP and HR of the respondents. The results are indicative and might be helpful in urban environmental planning to improve the well-being of urban traffic corridor users.

Health effects of filtering facepiece respirators: Systematic review of pulmonary and cardiovascular effects

Filtering facepiece respirators (FFRs) were introduced to protect the wearer by removing small particles from inspired air. FFRs are now also used to reduce the spread of transmissible agents from the wearer and are worn outside traditional healthcare and other workplaces. The COVID-19 pandemic increased concerns about potential adverse effects on wearers. A PUBMED query retrieved articles through June 2022. Abstracts and selected full-text articles were systematically reviewed by the authors. This article focuses upon cardiopulmonary physiologic effects (e.g., ventilation, CO₂ elimination, oxygen uptake, and respiratory control) with emphasis upon current and potential research methods as well as summarizing results. 1985 records were identified, of which only 26% were published before 2020. FFR effects on CO₂ elimination appear more likely to be significant than effects on oxygenation or cardiovascular function. While FFRs appear well tolerated by healthy persons, more research is needed for those with pulmonary or cardiac disorders, and for children. Many traditional pulmonary exercise study methods require special care when applied to filtering facepiece respirators. Studying additional parameters may explain the paradox of many subjective discomfort reports despite very limited physiologic effects.

The pathophysiological and molecular mechanisms of atmospheric PM2.5 affecting cardiovascular health: A review

BACKGROUND

Exposure to ambient fine particulate matter (PM2.5, with aerodynamic diameter less than 2.5 µm) is a leading environmental risk factor for global cardiovascular health concern.

OBJECTIVE

To provide a roadmap for those new to this field, we reviewed the new insights into the pathophysiological and cellular/molecular mechanisms of PM2.5 responsible for cardiovascular health.

MAIN FINDINGS

PM2.5 is able to disrupt multiple physiological barriers integrity and translocate into the systemic circulation and get access to a range of secondary target organs. An ever-growing body of epidemiological and controlled exposure studies has evidenced a causal relationship between PM2.5 exposure and cardiovascular morbidity and mortality. A variety of cellular and molecular biology mechanisms responsible for the detrimental cardiovascular outcomes attributable to PM2.5 exposure have been described, including metabolic activation, oxidative stress, genotoxicity, inflammation, dysregulation of Ca2+ signaling, disturbance of autophagy, and induction of apoptosis, by which PM2.5 exposure impacts the functions and fates of multiple target cells in cardiovascular system or related organs and further alters a series of pathophysiological processes, such as cardiac autonomic nervous system imbalance, increasing blood pressure, metabolic disorder, accelerated atherosclerosis and plaque vulnerability, platelet aggregation and thrombosis, and disruption in cardiac structure and function, ultimately leading to cardiovascular events and death. Therein, oxidative stress and inflammation were suggested to play pivotal roles in those pathophysiological processes.

CONCLUSION

Those biology mechanisms have deepen insights into the etiology, course, prevention and treatment of this public health concern, although the underlying mechanisms have not yet been entirely clarified.

The influence of N95 and FFP2 masks on cardiorespiratory variables in healthy individuals during aerobic exercise: a systematic review and meta-analysis

OBJECTIVE

In view of the current COVID-19 pandemic, the objective of this study was to determine, through a systematic review and meta-analysis, whether the use of N95/FFP2 masks during aerobic exercise has a significant impact on HR, RR, SpO2, and blood pressure (BP) in healthy individuals.

METHODS

We searched the MEDLINE database for studies published in English between 2005 and 2021. To reduce bias and increase reliability, only randomized controlled trials and randomized crossover clinical trials were considered for inclusion. The selected outcomes included HR, RR, SpO2, and BP, with perceived exertion being evaluated by means of the Borg scale.

RESULTS

Eight controlled trials were included in the meta-analysis. Seven evaluated HR (p > 0.05), five evaluated RR (p > 0.05), five evaluated SpO2 and BP (p > 0.05 for both), and six evaluated perceived exertion, presenting controversial results such as risk ratios that were grouped for each variable.

CONCLUSIONS

This study suggests that N95 and FFP2 masks do not have significant effects on HR, RR, SpO2, and BP during aerobic exercise in healthy individuals.

Particulate matter 2.5, metropolitan status, and heart failure outcomes in US counties: A nationwide ecologic analysis

The relationship between particulate matter with a diameter of 2.5 micrometers or less (PM2.5) and heart failure (HF) hospitalizations and mortality in the US is unclear. Prior studies are limited to studying the effects of daily PM2.5 exposure on HF hospitalizations in specific geographic regions. Because PM2.5 can vary by geography, this study examines the effects of annual ambient PM2.5 exposure on HF hospitalizations and mortality at a county-level across the US. A cross-sectional analysis of county-level ambient PM2.5 concentration, HF hospitalizations, and HF mortality across 3135 US counties nationwide was performed, adjusting for county-level demographics, socioeconomic factors, comorbidities, and healthcare-associated behaviors. There was a moderate correlation between county PM2.5 and HF hospitalization among Medicare beneficiaries (r = 0.41) and a weak correlation between county PM2.5 and HF mortality (r = 0.08) (p-values < 0.01). After adjustment for various county level covariates, every 1 ug/m3 increase in annual PM2.5 concentration was associated with an increase of 0.51 HF Hospitalizations/1,000 Medicare Beneficiaries and 0.74 HF deaths/100,000 residents (p-values < 0.05). In addition, the relationship between PM2.5 and HF hospitalizations was similar when factoring in metropolitan status of the counties. In conclusion, increased ambient PM2.5 concentration level was associated with increased incidence of HF hospitalizations and mortality at the county level across the US. This calls for future studies exploring policies that reduce ambient particulate matter pollution and their downstream effects on potentially improving HF outcomes.

Cardiopulmonary benefits of respirator intervention against near road ambient particulate matters in healthy young adults: A randomized, blinded, crossover, multi-city study

Wearing a respirator is generally the most convenient individual intervention against ambient particulate matter (PM), and therefore there has been considerable research into its effectiveness. However, the effects of respirator intervention under different PM concentration settings have been insufficiently elucidated. We conducted a randomized, blinded, crossover intervention study in four representative cities in China in which 128 healthy university students spent 2-h walking along a busy road wearing either a real or a sham respirator and then spent the next 5-h indoors away from traffic pollution. Lung function, blood pressure, and heart rate variability were continuously measured throughout the visit. Linear mixed-effect models were fitted to evaluate the protective effects of respirator intervention on the cardiopulmonary indicators. Results showed that the beneficial effects of respirator intervention were only occasionally significant at specific time points or in specific cities or in selected parameters. Overall, respirator intervention was associated with reduced SBP (6.2 vs. 11.5 mmHg compared to baseline, p < 0.05) and increased LF (44 vs. 35 ms² compared to baseline, p < 0.05) over the 2-h walk, but no significant effects were found over the 7-h period. Respirators have significant effect modifications on the associations between PM_2.5/PM₁₀ and the cardiopulmonary indicators, but the directions of effects were inconsistent. The intercity difference in the effects of respirator intervention was found significant, with Taiyuan and Shanghai to be the two cities with lower personal PM concentrations but more pronounced benefits. In conclusion, reducing personal exposure to PM can have some beneficial effects in some scenarios. However, respirators may not provide sufficient protection from air pollution overall, and we should avoid over-reliance on respirators and accelerate efforts to reduce emissions of pollutants in the first place. Despite standardized procedures, we found inconsistency in results across cities, consistent with the previous literature.

A Systematic Review of Whether the Use of N95 Respirator Masks Decreases the Incidence of Cardiovascular Disease in the General Population

The usage of masks such as the N95 has increased exponentially worldwide. With the ever-increasing global rates of cardiovascular disease, it is vital that preventative measures are adopted to help tackle this crisis. N95 masks have been promoted as health prevention odysseys in the battle against viruses such as COVID-19. A systematic review was conducted on whether the N95 masks could help improve our cardiovascular health. Our data sources included PubMed, Medline and Scopus. Eleven studies met the eligibility criteria to be included in the review. N95 mask usage led to increased reports of dyspnoea, however, no significant effect was seen on blood pressure. N95 masks also showed improvement in aortic parameters. While encouraging results were yielded, further focussed studies on the use of N95 masks and the effect on various cardiovascular parameters would help strengthen the association.

Effects of respirators to reduce fine particulate matter exposures on blood pressure and heart rate variability: A systematic review and meta-analysis

Particulate-filtering respirators (PFRs) have been recommended as a practical personal-level intervention to protect individuals from the health effects of particulate matter exposure. However, the cardiovascular benefits of PFRs including improvements in key surrogate endpoints remain unclear. We performed a systematic review and meta-analysis of randomized studies (wearing versus not wearing PFRs) reporting the effects on blood pressure (BP) and heart rate variability (HRV). The search was performed on January 3, 2022 to identify published papers until this date. We queried three English databases, including PubMed, Web of Science Core Collection and Scopus. Of 527 articles identified, eight trials enrolling 312 participants (mean age ± standard deviation: 36 ± 19.8; 132 female) met our inclusion criteria for analyses. Study participants wore PFRs from 2 to 48 h during intervention periods. Wearing PFRs was associated with a non-significant pooled mean difference of -0.78 mmHg (95% confidence interval [CI]: -2.06, 0.50) and -0.49 mmHg (95%CI: -1.37, 0.38) in systolic and diastolic BP (SBP and DBP). There was a marginally significant reduction of mean arterial pressure (MAP) by nearly 1.1 mmHg (95%CI: -2.13, 0.01). The use of PFRs was associated with a significant increase of 38.92 ms2 (95%CI: 1.07, 76.77) in pooled mean high frequency (power in the high frequency band (0.15-0.4 Hz)) and a reduction in the low (power in the low frequency band (0.04-0.15Hz))-to-high frequency ratio [-0.14 (95%CI: -0.27, 0.00)]. Other HRV indices were not significantly changed. Our meta-analysis demonstrates modest or non-significant improvements in BP and many HRV parameters from wearing PFRs over brief periods. However, these findings are limited by the small number of trials as well as variations in experimental designs and durations. Given the mounting global public health threat posed by air pollution, larger-scale trials are warranted to elucidate more conclusively the potential health benefits of PFRs.

Glucose Metabolic Disorders Enhance Vascular Dysfunction Triggered by Particulate Air Pollution: a Panel Study

BACKGROUND

Vascular dysfunction is a biological pathway whereby particulate matter (PM) exerts deleterious cardiovascular effects. The effects of ambient PM on vascular function in prediabetic individuals are unclear.

METHODS

A panel study recruited 112 Beijing residents with and without prediabetes. Multiple vascular function indices were measured up to 7 times. The associations between vascular function indices and short-term exposure to ambient PM, including fine particulate matter (PM_2.5), ultrafine particles, accumulation mode particles, and black carbon, and the modification of these associations by glucose metabolic status were examined using linear mixed-effects models.

RESULTS

Increases in brachial artery pulse pressure, central aortic pulse pressure, and ejection duration, and decreases in subendocardial viability ratio and reactive hyperemia index were significantly associated with at least one PM pollutant in all participants, indicating increased vascular dysfunction. For example, for an interquartile range increment in 5-day moving average ultrafine particles, brachial artery pulse pressure, and central aortic pulse pressure increased 5.4% (0.8%-10.4%) and 6.2% (1.2%-11.5%), respectively. Additionally, PM-associated changes in vascular function differed according to glucose metabolic status. Among participants with high fasting blood glucose levels (≥6.1 mmol/L), PM exposure was significantly associated with increased brachial artery systolic blood pressure, central aortic systolic blood pressure, brachial artery pulse pressure, central aortic pulse pressure, and augmentation pressure normalized to a heart rate of 75 bpm and decreased subendocardial viability ratio and reactive hyperemia index. Weaker or null associations were observed in the low-fasting blood glucose group.

CONCLUSIONS

Glucose metabolic disorders may exacerbate vascular dysfunction associated with short-term ambient PM exposure.

Personal Interventions to Reduce Exposure to Outdoor Air Pollution

Unhealthy levels of air pollution are breathed by billions of people worldwide, and air pollution is the leading environmental cause of death and disability globally. Efforts to reduce air pollution at its many sources have had limited success, and in many areas of the world, poor air quality continues to worsen. Personal interventions to reduce exposure to air pollution include avoiding sources, staying indoors, filtering indoor air, using face masks, and limiting physical activity when and where air pollution levels are elevated. The effectiveness of these interventions varies widely with circumstances and conditions of use. Compared with upstream reduction or control of emissions, personal interventions place burdens and risk of adverse unintended consequences on individuals. We review evidence regarding the balance of benefits and potential harms of personal interventions for reducing exposure to outdoor air pollution, which merit careful consideration before making public health recommendations with regard to who should use personal interventions and where, when, and how they should be used. Expected final online publication date for the Annual Review of Public Health, Volume 43 is April 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Environmental risk factors and cardiovascular diseases: a comprehensive review

Noncommunicable diseases (NCDs) are fatal for more than 38 million people each year and are thus the main contributors to the global burden of disease accounting for 70% of mortality. The majority of these deaths are caused by cardiovascular disease. The risk of NCDs is strongly associated with exposure to environmental stressors such as pollutants in the air, noise exposure, artificial light at night and climate change, including heat extremes, desert storms and wildfires. In addition to the traditional risk factors for cardiovascular disease such as diabetes, arterial hypertension, smoking, hypercholesterolemia and genetic predisposition, there is a growing body of evidence showing that physicochemical factors in the environment contribute significantly to the high NCD numbers. Furthermore, urbanization is associated with accumulation and intensification of these stressors. This comprehensive expert review will summarize the epidemiology and pathophysiology of environmental stressors with a focus on cardiovascular NCDs. We will also discuss solutions and mitigation measures to lower the impact of environmental risk factors with focus on cardiovascular disease.

Particulate respirator use and blood pressure: A systematic review and meta-analysis

People use a particulate respirator in order to reduce exposure to ambient fine particulate matter (PM_2.5). Acute exposure to PM_2.5 is known to increase blood pressure. However, systematic reviews or meta-analyses on blood pressure-related benefits of using a particulate respirator is lacking. Therefore, we reviewed randomized crossover intervention studies on blood pressure-related effects of particulate matter respirator use. We conducted a literature review of articles found on Embase, Medline, and Cochrane library on August 31, 2020. The study outcomes were systolic and diastolic blood pressure and mean arterial pressure. A random-effect model was used in the meta-analysis. Subgroup analyses, based on age (adult < 60 years, elderly ≥ 60 years), personal PM_2.5 exposure levels (High: ≥ 25 μg/m³, Low: < 25 μg/m³), and types of monitoring methods (ambulatory and resting blood pressure) were conducted. We identified 297 references, and seven studies were included in our systematic review. None of the studies used a sham respirator as control and complete allocation concealment and blinding were impossible. The use of a particulate respirator was associated with a -1.23 mmHg (95% confidence interval (CI): -2.53, 0.07) change in systolic blood pressure and a -1.57 mmHg (95% CI: -3.85, 0.71) change in mean arterial pressure. There were significant heterogeneities and possibilities for publication bias. The subgroup analyses revealed that studies involving elderly individuals, those conducted in high PM_2.5 personal exposure, and those in which resting blood pressure was monitored demonstrated a larger decrease in blood pressure resulting from respirator use. Further intervention studies with a large sample size and subjects with diverse characteristics and different personal PM_2.5 levels may add the evidence to current literature.

Individual-level interventions to reduce personal exposure to outdoor air pollution and their effects on people with long-term respiratory conditions

BACKGROUND

More than 90% of the global population lives in areas exceeding World Health Organization air quality limits. More than four million people each year are thought to die early due to air pollution, and poor air quality is thought to reduce an average European's life expectancy by one year. Individuals may be able to reduce health risks through interventions such as masks, behavioural changes and use of air quality alerts. To date, evidence is lacking about the efficacy and safety of such interventions for the general population and people with long-term respiratory conditions. This topic, and the review question relating to supporting evidence to avoid or lessen the effects of air pollution, emerged directly from a group of people with chronic obstructive pulmonary disease (COPD) in South London, UK.

OBJECTIVES

1. To assess the efficacy, safety and acceptability of individual-level interventions that aim to help people with or without chronic respiratory conditions to reduce their exposure to outdoor air pollution. 2. To assess the efficacy, safety and acceptability of individual-level interventions that aim to help people with chronic respiratory conditions reduce the personal impact of outdoor air pollution and improve health outcomes.

SEARCH METHODS

We identified studies from the Cochrane Airways Trials Register, Cochrane Central Register of Controlled Trials, and other major databases. We did not restrict our searches by date, language or publication type and included a search of the grey literature (e.g. unpublished information). We conducted the most recent search on 16 October 2020.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and non-randomised studies (NRS) that included a comparison treatment arm, in adults and children that investigated the effectiveness of an individual-level intervention to reduce risks of outdoor air pollution. We included studies in healthy individuals and those in people with long-term respiratory conditions. We excluded studies which focused on non-respiratory long-term conditions, such as cardiovascular disease. We did not restrict eligibility of studies based on outcomes.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Two review authors independently selected trials for inclusion, extracted study characteristics and outcome data, and assessed risk of bias using the Cochrane Risk of Bias tool for RCTs and the Risk Of Bias In Non-randomised Studies - of Interventions (ROBINS-I) as appropriate. One review author entered data into the review; this was spot-checked by a second author. We planned to meta-analyse results from RCTs and NRS separately, using a random-effects model. This was not possible, so we presented evidence narratively. We assessed certainty of the evidence using the GRADE approach. Primary outcomes were: measures of air pollution exposure; exacerbation of respiratory conditions; hospital admissions; quality of life; and serious adverse events.

MAIN RESULTS

We identified 11 studies (3372 participants) meeting our inclusion criteria (10 RCTs and one NRS). Participants' ages ranged from 18 to 74 years, and the duration of studies ranged from 24 hours to 104 weeks. Six cross-over studies recruited healthy adults and five parallel studies included either people with pre-existing conditions (three studies) or only pregnant women (two studies). Interventions included masks (e.g. an N95 mask designed to filter out airborne particles) (five studies), an alternative cycle route (one study), air quality alerts and education (five studies). Studies were set in Australia, China, Iran, the UK, and the USA. Due to the diversity of study designs, populations, interventions and outcomes, we did not perform any meta-analyses and instead summarised results narratively. We judged both RCTs and the NRS to be at risk of bias from lack of blinding and lack of clarity regarding selection methods. Many studies did not provide a prepublished protocol or trial registration. From five studies (184 participants), we found that masks or altered cycle routes may have little or no impact on physiological markers of air pollution exposure (e.g. blood pressure and heart rate variability), but we are very uncertain about this estimate using the GRADE approach. We found conflicting evidence regarding health care usage from three studies of air pollution alerts, with one non-randomised cross-over trial (35 participants) reporting an increase in emergency hospital attendances and admissions, but the other two randomised parallel trials (1553 participants) reporting little to no difference. We also gave the evidence for this outcome a very uncertain GRADE rating. None of our included trials reported respiratory exacerbations, quality of life or serious adverse events. Secondary outcomes were not well reported, but indicated inconsistent impacts of air quality alerts and education interventions on adherence, with some trials reporting improvements in the intervention groups and others reporting little or no difference. Symptoms were reported by three trials, with one randomised cross-over trial (15 participants) reporting a small increase in breathing difficulties associated with the mask intervention, one non-randomised cross-over trial (35 participants) reporting reduced throat and nasal irritation in the lower-pollution cycle route group (but no clear difference in other respiratory symptoms), and another randomised parallel trial (519 participants) reporting no clear difference in symptoms between those who received a smog warning and those who did not.

AUTHORS' CONCLUSIONS

The lack of evidence and study diversity has limited the conclusions of this review. Using a mask or a lower-pollution cycle route may mitigate some of the physiological impacts from air pollution, but evidence was very uncertain. We found conflicting results for other outcomes, including health care usage, symptoms and adherence/behaviour change. We did not find evidence for adverse events. Funders should consider commissioning larger, longer studies, using high-quality and well-described methods, recruiting participants with pre-existing respiratory conditions. Studies should report outcomes of importance to people with respiratory conditions, such as exacerbations, hospital admissions, quality of life and adverse events.

Role of atmospheric particulate matter exposure in COVID-19 and other health risks in human: A review

Due to intense industrialization and urbanization, air pollution has become a serious global concern as a hazard to human health. Epidemiological studies found that exposure to atmospheric particulate matter (PM) causes severe health problems in human and significant damage to the physiological systems. In recent days, PM exposure could be related as a carrier for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus transmission and Coronavirus disease 2019 (COVID-19) infection. Hence, it is important to understand the adverse effects of PM in human health. This review aims to provide insights on the detrimental effects of PM in various human health problems including respiratory, circulatory, nervous, and immune system along with their possible toxicity mechanisms. Overall, this review highlights the potential relationship of PM with several life-limiting human diseases and their significance for better management strategies.

Cardiovascular health effects of wearing a particulate-filtering respirator to reduce particulate matter exposure: a randomized crossover trial

This randomized crossover trial sought to determine whether wearing a high-efficiency particulate-filtering respirator (PFR) improves cardiovascular function over 48 h among healthy college students in Tehran. This trial was conducted from February 14th to 23rd, 2019 and twenty-six participants completed two 48-h intervention periods. Brachial blood pressure (BP) measured by 24-h ambulatory monitoring was the primary health outcome. Secondary outcomes included 48-h heart rate variability (HRV) indices, high-sensitive cardiac troponin (hs-TnT) and other biomarkers. The participants wore the PFR between 10.2 and 11.1 h while awake during the interventions. More than 80% of participants reported increased respiratory resistance while wearing the PFR due to a lack of an exhalation valve. There were no significant differences in brachial BP levels between subjects who wore PFR respirator and those did not. Except for high frequency (HF) power and heart rate (HR), no significant differences between interventions were observed for other HRV metrics. Wearing the PFR led to an increase of 66.0 ms² (95% confidence interval [CI], 9.6-110.5) and 79.6 ms² (95% CI, 19.0-140.1) in HF power during the first day when the two groups of participants wore the PFR. Night-time HR was significantly increased during the PFR intervention period. Other secondary outcomes were not significantly different between interventions. It is plausible that incomplete exposure reduction due to wearing the PFR less than half of the time or increased respiratory resistance mitigated potential health benefits. Additional trials are warranted to validate the CV protection of wearing PFRs in heavily-polluted cities.

[The use of anti-pollution masks in daily life - a review]

INTRODUCTION

"Anti-pollution" masks are a form of personal protective equipment intended to ensure filtration of ambient particulate air pollution.

STATE OF THE ART

Although according to tests performed in the lab, their filtration power is high, the filtering efficiency of these masks in real conditions of use, that is to say, during physical effort, is generally lower than that established in the laboratory and this information is rarely available on commercial products on sale. Clinical studies, which are rarely double-blind, demonstrate a lower incidence of symptoms and a somewhat better cardiac performance when exercise is performed while wearing a mask. For short-term use, the tolerance of these masks is fair.

PERSPECTIVES

There is room for technical improvements in mask design improved fitting to the face, lowering inspiratory resistance and dead space, as well as preventing the accumulation of humidity on the mask. Manufacturers should include information in their packaging on the filtering power and design masks usable by children. Clinical studies should be performed to assess the long-term safety and effectiveness of mask in susceptible populations, especially people with asthma.

CONCLUSION

Anti-pollution filtering face piece respirators have a theoretical high filtering power towards particles, but their efficiency in real-life conditions is more limited. Because such devices may confer to users a false sense of protection, the French agency on environment and health do not support their use.

Health effects of wildfire smoke in children and public health tools: a narrative review

Wildfire smoke is an increasing environmental health threat to which children are particularly vulnerable, for both physiologic and behavioral reasons. To address the need for improved public health messaging this review summarizes current knowledge and knowledge gaps in the health effects of wildfire smoke in children, as well as tools for public health response aimed at children, including consideration of low-cost sensor data, respirators, and exposures in school environments. There is an established literature of health effects in children from components of ambient air pollution, which are also present in wildfire smoke, and an emerging literature on the effects of wildfire smoke, particularly for respiratory outcomes. Low-cost particulate sensors demonstrate the spatial variability of pollution, including wildfire smoke, where children live and play. Surgical masks and respirators can provide limited protection for children during wildfire events, with expected decreases of roughly 20%  and 80% for surgical masks and N95 respirators, respectively. Schools should improve filtration to reduce exposure of our nation's children to smoke during wildfire events. The evidence base described may help clinical and public health authorities provide accurate information to families to improve their decision making.

Personal-Level Protective Actions Against Particulate Matter Air Pollution Exposure: A Scientific Statement From the American Heart Association

Since the publication of the last American Heart Association scientific statement on air pollution and cardiovascular disease in 2010, unequivocal evidence of the causal role of fine particulate matter air pollution (PM2.5, or particulate matter ≤2.5 μm in diameter) in cardiovascular disease has emerged. There is a compelling case to provide the public with practical personalized approaches to reduce the health effects of PM2.5. Such interventions would be applicable not only to individuals in heavily polluted countries, high-risk or susceptible individuals living in cleaner environments, and microenvironments with higher pollution exposures, but also to those traveling to locations with high levels of PM2.5. The overarching motivation for this document is to summarize the current evidence supporting personal-level strategies to prevent the adverse cardiovascular effects of PM2.5, guide the use of the most proven/viable approaches, obviate the use of ineffective measures, and avoid unwarranted interventions. The significance of this statement relates not only to the global importance of PM2.5, but also to its focus on the most tested interventions and viable approaches directed at particulate matter air pollution. The writing group sought to provide expert consensus opinions on personal-level measures recognizing the current uncertainty and limited evidence base for many interventions. In doing so, the writing group acknowledges that its intent is to assist other agencies charged with protecting public health, without minimizing the personal choice considerations of an individual who may decide to use these interventions in the face of ongoing air pollution exposure.

Acute cardiovascular health effects in a panel study of personal exposure to traffic-related air pollutants and noise in Toronto, Canada

Urban populations are often simultaneously exposed to air pollution and environmental noise, which are independently associated with cardiovascular disease. Few studies have examined acute physiologic responses to both air and noise pollution using personal exposure measures. We conducted a repeated measures panel study of air pollution and noise in 46 non-smoking adults in Toronto, Canada. Data were analyzed using linear mixed-effects models and weighted cumulative exposure modeling of recent exposure. We examined acute changes in cardiovascular health effects of personal (ultrafine particles, black carbon) and regional (PM_2.5, NO₂, O₃, O_x) measurements of air pollution and the role of personal noise exposure as a confounder of these associations. We observed adverse changes in subclinical cardiovascular outcomes in response to both air pollution and noise, including changes in endothelial function and heart rate variability (HRV). Our findings show that personal noise exposures can confound associations for air pollutants, particularly with HRV, and that impacts of air pollution and noise on HRV occur soon after exposure. Thus, both noise and air pollution have a measurable impact on cardiovascular physiology. Noise should be considered alongside air pollution in future studies to elucidate the combined impacts of these exposures in urban environments.

Can respirator face masks in a developing country reduce exposure to ambient particulate matter?

Respirator face masks (RFMs) as a personal-level intervention is increasingly being utilized to reduce ambient particulate matter (PM) exposure, globally. We tested the effectiveness of 50 commercially available ones in reducing the exposure of ambient particle number concentrations (PNC), PM₁₀, PM_2.5, and PM₁ (PM ≤ 10, 2.5, and 1 μm in diameter, respectively) in a traffic-affected urban site in Tehran. To examine the efficiency of RFMs, we applied a specific experimental setup including vacuum pumps, dummy heads, connecting tubes, glass chambers, and GRIMM Aerosol Spectrometer to measure all metrics after dummy heads. The average effectiveness of RFMs was in the range of 0.7-83.5%, 3.5-68.1%, 0.8-46.1%, and 0.4-32.2% in reducing ambient PNC, PM₁₀, PM_2.5, and PM₁, respectively. Considering all metrics, the highest effectiveness was observed always for Biomask, followed by 3 M 9332, due to their well-designed physical characteristics (e.g., adjustable nose clip for any face/nose shape, and size, soft inner material in the nose panel to provide a secure seal against leakage, adjustable or elasticated straps/ear loops to better adjust on any face). Biomask reduced ambient PM₁₀ with a mean value of 94.6 μg m^-3 (minimum-maximum: 51.7-100.3 μg m^-3), whereas it filtered on average just 29.0 μg m^-3 (25.7-43.5 μg m^-3) of ambient PM_2.5 and 18.2 μg m^-3 (14.7-21.8 μg m^-3) of PM₁. A fuzzy analytical hierarchy process to find the most important design-related factors of RFMs affecting their effectiveness, which showed the exhalation valve and its diaphragm (20.4%), nose clip (19.7%), and cheek flaps (18.6%) are ranked as the main design-related variables. The fuzzy technique for order preference by similarity to ideal solution indicated that Biomask and 3M 9332 had scores of 1 and 0.97, the highest scores compared with other RFMs. This study provides crucial evidence-based results to elucidate the effectiveness and design-related factors of RFMs in real-environmental circumstances.

Acute effects of ambient particulate matter on blood pressure in office workers

Exposure to ambient particulate matter with a diameter of <2.5 μm (PM_2.5) has been linked to increases in blood pressure. The aim of this study was to assess the effects of short-term exposure to PM_2.5 on blood pressure in office workers in Beijing, China. A total of 4801 individuals aged 18-60 years underwent an annual medical examination between 2013 and 2017. Levels of air pollutants were obtained from 35 fixed monitoring stations and correlated with the employment location of each participant to predict personal exposure via kriging interpolation. Linear mixed-effects models were used to estimate the changes in blood pressure associated with PM_2.5 exposure at various lag times. After adjusting for personal characteristics and other potential confounders, each interquartile range increase in PM_2.5 was associated with a 0.413-mmHg (95% confidence interval [CI]: 0.252-0.573), 0.171-mmHg (95% CI: 0.053-0.288), 0.278-mmHg (95% CI: 0.152-0.404), and 0.241-mmHg (95% CI: 0.120-0.362) increase in systolic blood pressure, diastolic blood pressure, pulse pressure, and mean arterial pressure, respectively (p < 0.05). Men, individuals previously diagnosed with hypertension, and subjects working in the northern districts of Beijing had larger changes in blood pressure, and the effect sizes were 0.477-mmHg (95% CI: 0.286-0.669), 0.851-mmHg (95% CI: 0.306-1.397, and 0.672-mmHg (95% CI: 0.405-0.940). The findings suggested that exposure to PM_2.5 had adverse effects on blood pressure, especially among males and hypertensive patients.

Biomarkers of exposure, effect, and susceptibility in occupational exposure to traffic-related air pollution: A review

There is a well-recognized association between environmental air pollution exposure and several human diseases. However, the relationship between diseases related to occupational air pollution exposure on roads and high levels of traffic-related air pollutants (TRAPs) is less substantiated. Biomarkers are essential tools in environmental and occupational toxicology, and studies on new biomarkers are increasingly relevant due to the need to determine early biomarkers to be assessed in exposure conditions. This review aimed to investigate the main advances in the biomonitoring of subjects occupationally exposed to air pollution, as well as to summarize the biomarkers of exposure, effect, and susceptibility. Furthermore, we discuss how biomarkers could be used to complement the current application of methods used to assess occupational exposures to xenobiotics present in air pollution. The databases used in the preparation of this review were PubMed, Scopus, and Science Direct. Considering the significant deleterious effects on health associated with chronic occupational exposure to xenobiotics, this topic deserves attention. As it is difficult to avoid occupational exposure to TRAPs, biomonitoring should be applied as a strategy to reduce the toxic effects of workplace exposure.