Proposed pathophysiologic framework to explain some excess cardiovascular death associated with ambient air particle pollution: Insights for public health translation

Lifetime losses due to cardiovascular and respiratory diseases attributable to air pollution in polluted and unpolluted areas

The article assesses differences in lifetime losses caused by premature deaths from cardiopulmonary disease in populations living in areas with different environmental burdens. The results provide different perspectives on data on total years lost and lifetime losses attributable to air pollution. Such lifetime losses in the industrial area related to cardiovascular causes of death are 7.6 or 5.1 years per male or female deceased, representing an average lifetime loss of 0.01907 years (i.e. 7 days) per 1 male or 0.01273 years (i.e. 4.6 days) per 1 female in the entire population. Losses related to cerebrovascular or respiratory causes of death are about 5.4 or 5.9 years per 1 deceased male or 3.9 or 5 years per 1 deceased female, respectively, which represents a loss of 0.00481 (1.8 days), or 0.00148 years (0.5 days) per 1 male or 0.00466 (1.7 days), or 0.00058 years (0.2 days) per 1 female.

Long-term exposure to ambient air pollution and measures of central hemodynamics and arterial stiffness among multiethnic Chicago residents

Objectives

To examine whether air pollution exposure is associated with central hemodynamic and brachial artery stiffness parameters.

Methods

We assessed central hemodynamic parameters, brachial artery stiffness measures [including brachial artery distensibility (BAD), compliance (BAC), and resistance (BAR)] using waveform analysis of the arterial pressure signals obtained from a standard cuff sphygmomanometer (DynaPulse2000A, San Diego, CA). The long-term exposures to particles with an aerodynamic diameter < 2.5μm (PM2.5) and nitrogen dioxide (NO2) for the 3-year periods prior to enrollment were estimated at residential addresses using fine-scale intra-urban spatiotemporal models. Linear mixed models adjusted for potential confounders were used to examine associations between air pollution exposures and health outcomes.

Results

The cross-sectional study included 2,387 Chicago residents (76% African Americans) enrolled in the ChicagO Multiethnic Prevention And Surveillance Study (COMPASS) during 2013-2018 with validated address information, PM2.5 or NO2, key covariates, and hemodynamics measurements. We observed long-term concentrations of PM2.5 and NO2 to be positively associated with central systolic, pulse pressure and BAR, and negatively associated with BAD, and BAC after adjusting for relevant covariates. A 1-μg/m3 increment in preceding 3-year exposures to PM2.5 was associated with 1.8 mmHg higher central systolic (95% CI: 0.98, 4.16), 1.0 mmHg higher central pulse pressure (95% CI: 0.42, 2.87), a 0.56%mmHg lower BAD (95% CI: -0.81, -0.30), and a 0.009 mL/mmHg lower BAC (95% CI: -0.01, -0.01).

Conclusion

This population-based study provides evidence that long-term exposures to PM2.5 and NO2 is related to central BP and arterial stiffness parameters, especially among African Americans.

Association between short-term exposure to air pollutants and cause-specific daily mortality in Italy. A nationwide analysis

BACKGROUND/AIM

Daily air pollution has been linked with mortality from urban studies. Associations in rural areas are still unclear and there is growing interest in testing the role that air pollution has on other causes of death. This study aims to evaluate the association between daily air pollution and cause-specific mortality in all 8092 Italian municipalities.

METHODS

Natural, cardiovascular, cardiac, ischemic, cerebrovascular, respiratory, metabolic, diabetes, nervous and psychiatric causes of death occurred in Italy were extracted during 2013-2015. Daily ambient PM₁₀, PM_2.5 and NO₂ concentrations were estimated through machine learning algorithms. The associations between air pollutants and cause-specific mortality were estimated with a time-series approach using a two-stage analytic protocol where area-specific over-dispersed Poisson regression models where fit in the first stage, followed by a meta-analysis in the second. We tested for effect modification by sex, age class and the degree of urbanisation of the municipality.

RESULTS

We estimated a positive association between PM₁₀ and PM_2.5 and the mortality from natural, cardiovascular, cardiac, respiratory and nervous system causes, but not with metabolic or psychiatric causes of death. In particular, mortality from nervous diseases increased by 4.55% (95% CI: 2.51-6.63) and 9.64% (95% CI: 5.76-13.65) for increments of 10 μg/m³ in PM₁₀ and PM_2.5 (lag 0-5 days), respectively. NO₂ was positively associated with respiratory (6.68% (95% CI: 1.04-12.62)) and metabolic (7.30% (95% CI: 1.03-13.95)) mortality for increments of 10 μg/m³ (lag 0-5). Higher associations with natural mortality were found among the elderly, while there were no differential effects between sex or between rural and urban areas.

CONCLUSIONS

Short-term exposure to particulate matter was associated with mortality from nervous diseases. Mortality from metabolic diseases was associated with NO₂ exposure. Other associations are confirmed and updated, including the contribution of lowly urbanised areas. Health effects were also found in suburban and rural areas.

A nursing socio-environmental approach for acute pesticide poisoning: A qualitative focus group study

AIM

To explore the experiences and perceptions of final-year nursing students in assessing and managing acute pesticide poisoning using a socio-environmental care approach in a primary health care simulation-based scenario.

DESIGN

A qualitative descriptive study was conducted using focus groups.

METHODS

Twelve focus groups were held, with 114 fourth-year nursing students. The study was carried out from September to November 2021. To grant an in-depth analysis of the collected data, a thematic analysis was used.

RESULTS

After our data analysis, three main themes emerged: (i) experiences of an acute pesticide poisoning case in a simulation-based scenario; (ii) environmental health nursing competencies for a culturally competent practice and (iii) social factors in prevention strategies.

CONCLUSIONS

Using a socio-environmental care approach with a primary care simulation-based poisoning case can provide a realistic public health clinical experience for local problems and prepare the context for the development of global citizenship values, as well as offer numerous opportunities to facilitate transformative learning, including Sustainable Development Goals (SDGs) into local nursing clinical practice.

IMPACT

Nurse managers, policymakers and educators must collaborate together to broaden their reach in teaching the role of the environment and social determinants of health through evidence-based care models, as well as actively contributing to the achievement of the SDGs to promote "glocal" competencies among nursing professionals.

Ambient air pollution and cardiovascular diseases: An umbrella review of systematic reviews and meta-analyses

The available evidence on the effects of ambient air pollution on cardiovascular diseases (CVDs) has increased substantially. In this umbrella review, we summarized the current epidemiological evidence from systematic reviews and meta-analyses linking ambient air pollution and CVDs, with a focus on geographical differences and vulnerable subpopulations. We performed a search strategy through multiple databases including articles between 2010 and 31 January 2021. We performed a quality assessment and evaluated the strength of evidence. Of the 56 included reviews, the most studied outcomes were stroke (22 reviews), all-cause CVD mortality, and morbidity (19). The strongest evidence was found between higher short- and long-term ambient air pollution exposure and all-cause CVD mortality and morbidity, stroke, blood pressure, and ischemic heart diseases (IHD). Short-term exposures to particulate matter <2.5 μm (PM_2.5 ), <10 μm (PM₁₀ ), and nitrogen oxides (NO_x ) were consistently associated with increased risks of hypertension and triggering of myocardial infarction (MI), and stroke (fatal and nonfatal). Long-term exposures of PM_2.5 were largely associated with increased risk of atherosclerosis, incident MI, hypertension, and incident stroke and stroke mortality. Few reviews evaluated other CVD outcomes including arrhythmias, atrial fibrillation, or heart failure but they generally reported positive statistical associations. Stronger associations were found in Asian countries and vulnerable subpopulations, especially among the elderly, cardiac patients, and people with higher weight status. Consistent with experimental data, this comprehensive umbrella review found strong evidence that higher levels of ambient air pollution increase the risk of CVDs, especially all-cause CVD mortality, stroke, and IHD. These results emphasize the importance of reducing the alarming levels of air pollution across the globe, especially in Asia, and among vulnerable subpopulations.

Biological Activities, Pharmacokinetics and Toxicity of Nootkatone: A Review

Abstract:

Plant-based drugs have a significant impact on modern therapeutics due to their vast array of pharmacological activities. The integration of herbal plants in the current healthcare system has emerged as a new field of research. It can be used for the identification of novel lead compound candidates for future drug development. Nootkatone is a sesquiterpene derivative and an isolate of grapefruit. Shreds of evidence illustrate that nootkatone targets few molecular mechanisms to exhibit its pharmacological activity and yet needs more exploration to be established. The current review is related to nootkatone, drafted through a literature search using research articles and books from different sources, including Science Direct, Google Scholar, Elsevier, PubMed, and Scopus. It has been reported to possess a wide range of pharmacological activities such as anti-inflammatory, anticancer, antibacterial, hepatoprotective, neuroprotective, and cardioprotective. Although preclinical studies in experimental animal models suggest that nootkatone has therapeutic potential, it is further warranted to evaluate its toxicity and pharmacokinetic parameters before being applied to humans. Hence in the present review, we have summarized the scientific knowledge on nootkatone with a particular emphasis on its pharmacological properties to encourage researchers for further exploration in preclinical and clinical settings.

Assessing the intra-urban variability of nitrogen oxides and ozone across a highly heterogeneous urban area

High-resolution air quality maps are critical towards assessing and understanding exposures to elevated air pollution in dense urban areas. However, these surfaces are rarely available in low- and middle-income countries that suffer from some of the highest air pollution levels worldwide. In this study, we make use of land use regressions (LURs) to generate annual and seasonal, high-resolution nitrogen dioxide (NO₂), nitrogen oxides (NO_x), and ozone (O₃) exposure surfaces for the Greater Beirut Area (GBA) in Lebanon. NO₂, NO_x and O₃ concentrations were monitored using passive samplers that were deployed at 55 pre-defined monitoring locations. The average annual concentrations of NO₂, NO_x, and O₃ across the GBA were 36.0, 89.7, and 26.9 ppb, respectively. Overall, the performance of the generated models was appropriate, with low biases, high model robustness, and acceptable R² values that ranged between 0.66 and 0.73 for NO₂, 0.56 and 0.60 for NO_x, and 0.54 and 0.65 for O₃. Traffic-related emissions as well as the operation of a fossil-fuel power plant were found to be the main contributors to the measured NO₂ and NO_x levels in the GBA, whereas they acted as sinks for O₃ concentrations. No seasonally significant differences were found for the NO₂ and NO_x pollution surfaces; as their seasonal and annual models were largely similar (Pearson's r > 0.85 for both pollutants). On the other hand, seasonal O₃ pollution surfaces were significantly different. The model results showed that around 99% of the population of the GBA were exposed to NO₂ levels that exceeded the World Health Organization defined annual standard.

Conditions of Aerogenic Exposure to Benzene and Genetic Status as Factors of Formation of Immune Profile Features in Men with Autonomic Regulation Disturbances

We studied the immunological status and polymorphic variants of candidate genes in men with disturbances of autonomic nervous regulation under conditions of aerogenic exposure to benzene. The group of men with pathology of the autonomic nervous system (autonomic dysfunction syndrome) living under conditions of aerogenic exposure to benzene is characterized by increased blood contamination with benzene, which 1.5-fold surpassed this parameter in the group of conventionally healthy men (p<0.05). The immune profile of the surveyed men is characterized by increased specific sensitization (IgG to benzene) and activation of apoptosis (TNFR, p53) and phagocytosis. The production of serum IgA was also increased (p<0.05) in men of this group. The content of CD127- lymphocytes significantly (p<0.05) exceeded the reference level against the background of a significantly reduced (p<0.05) level of CD3+CD95+ lymphocytes irrespective of the presence or absence of autonomic nervous system pathology in men with excessive haptenic load with benzene. The revealed features of the immune status of men with autonomic regulation disorders were significantly associated (OR>1; p<0.05) with the variant allele of the FOXP3 immune regulation gene (rs3761547) and with wild-type allele of the SOD2 superoxide dismutase gene (rs2758330) and the corresponding homozygous genotypes. The established features of immune regulation (hyperproduction of IgG to benzene, imbalance of apoptosis markers (CD127-, CD3+CD95+, p53, and TNFR) against the background of altered polymorphism of candidate genes (FOXP3, SOD2) form a complex of genetic and immunological markers of autonomic regulation disorders in men living under conditions of aerogenic exposure to benzene.

Evaluation of PM2.5 air pollution sources and cardiovascular health

Long-term air pollution exposure, notably fine particulate matter, is a global contributor to morbidity and mortality and a known risk factor for coronary artery disease (CAD) and myocardial infarctions (MI). Knowledge of impacts related to source-apportioned PM2.5 is limited. New modeling methods allow researchers to estimate source-specific long-term impacts on the prevalence of CAD and MI. The Catheterization Genetics (CATHGEN) cohort consists of patients who underwent a cardiac catheterization at Duke University Medical Center between 2002 and 2010. Severity of coronary blockage was determined by coronary angiography and converted into a binary indicator of clinical CAD. History of MI was extracted from medical records. Annual averages of source specific PM2.5 were estimated using an improved gas-constrained source apportionment model for North Carolina from 2002 to 2010. We tested six sources of PM2.5 mass for associations with CAD and MI using mixed effects multivariable logistic regression with a random intercept for county and multiple adjustments. PM2.5 fractions of ammonium bisulfate and ammonium nitrate were associated with increased prevalence of CAD (odds ratio [OR] 1.20; 95% CI = 1.11, 1.22 and OR 1.18; 95% CI = 1.05, 1.32, respectively). PM2.5 from ammonium bisulfate and ammonium nitrate were also associated with increased prevalence of MI (OR 1.20; 95% CI = 1.10, 1.29 and OR 1.35; 95% CI = 1.20, 1.53, respectively). Greater PM2.5 concentrations of ammonium bisulfate and ammonium nitrate are associated with greater MI and CAD prevalence. The association with bisulfate suggests aerosol acidity may play a role. Our findings suggest analyses of source specific PM2.5 mass can reveal novel associations.

Acute Exposure to Diesel Exhaust Increases Muscle Sympathetic Nerve Activity in Humans

Background

Diesel exhaust (DE) emissions are a major contributor to ambient air pollution and are strongly associated with cardiovascular morbidity and mortality. Exposure to traffic‐related particulate matter is linked with acute adverse cardiovascular events; however, the mechanisms are not fully understood. We examined the role of the autonomic nervous system during exposure to DE that has previously only been indirectly investigated.

Methods and Results

Using microneurography, we measured muscle sympathetic nerve activity (MSNA) directly in the peroneal nerve of 16 healthy individuals. MSNA, heart rate, and respiration were recorded while subjects rested breathing filtered air, filtered air with an exposure mask, and standardized diluted DE (300 µg/m³) through the exposure mask. Heart rate variability was assessed from an ECG. DE inhalation rapidly causes an increase in number of MSNA bursts as well as the size of bursts within 10 minutes, peaking by 30 minutes (P<0.001), compared with baseline filtered air with an exposure mask. No significant changes occurred in heart rate variability indices during DE exposure; however, MSNA frequency correlated negatively with total power (r²=0.294, P=0.03) and low frequency (r²=0.258, P=0.045). Heart rate correlated positively with MSNA frequency (r²=0.268, P=0.04) and the change in percentage of larger bursts (burst amplitude, height >50% of the maximum burst) from filtered air with an exposure mask (r²=0.368, P=0.013).

Conclusions

Our study provides direct evidence for the rapid modulation of the autonomic nervous system after exposure to DE, with an increase in MSNA. The quick increase in sympathetic outflow may explain the strong epidemiological data associating traffic‐related particulate matter to acute adverse cardiovascular events such as myocardial infarction.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02892279.

Peat smoke inhalation alters blood pressure, baroreflex sensitivity, and cardiac arrhythmia risk in rats

Wildland fires (WF) are linked to adverse health impacts related to poor air quality. The cardiovascular impacts of emissions from specific biomass sources are however unknown. The purpose of this study was to assess the cardiovascular impacts of a single exposure to peat smoke, a key regional WF air pollution source, and relate these to baroreceptor sensitivity and inflammation. Three-month-old male Wistar-Kyoto rats, implanted with radiotelemeters for continuous monitoring of heart rate (HR), blood pressure (BP), and spontaneous baroreflex sensitivity (BRS), were exposed once, for 1-hr, to filtered air or low (0.38 mg/m³ PM) or high (4.04 mg/m³) concentrations of peat smoke. Systemic markers of inflammation and sensitivity to aconitine-induced cardiac arrhythmias, a measure of latent myocardial vulnerability, were assessed in separate cohorts of rats 24 hr after exposure. PM size (low peat = 0.4-0.5 microns vs. high peat = 0.8-1.2 microns) and proportion of organic carbon (low peat = 77% vs. high peat = 65%) varied with exposure level. Exposure to high peat and to a lesser extent low peat increased systolic and diastolic BP relative to filtered air. In contrast, only exposure to low peat elevated BRS and aconitine-induced arrhythmogenesis relative to filtered air and increased circulating levels of low-density lipoprotein cholesterol, complement components C3 and C4, angiotensin-converting enzyme (ACE), and white blood cells. Taken together, exposure to peat smoke produced overt and latent cardiovascular consequences that were likely influenced by physicochemical characteristics of the smoke and associated adaptive homeostatic mechanisms.

Air Pollution and Central Nervous System Disease: A Review of the Impact of Fine Particulate Matter on Neurological Disorders

Background: It is widely known that the harmful effects of fine dust can cause various diseases. Research on the correlation between fine dust and health has been mainly focused on lung and cardiovascular diseases. By contrast, the effects of air pollution on the central nervous system (CNS) are not broadly recognized.

Findings: Air pollution can cause diverse neurological disorders as the result of inflammation of the nervous system, oxidative stress, activation of microglial cells, protein condensation, and cerebral vascular-barrier disorders, but uncertainty remains concerning the biological mechanisms by which air pollution produces neurological disease. Neuronal cell damage caused by fine dust, especially in fetuses and infants, can cause permanent brain damage or lead to neurological disease in adulthood.

Conclusion: It is necessary to study the air pollution–CNS disease connection with particular care and commitment. Moreover, the epidemiological and experimental study of the association between exposure to air pollution and CNS damage is critical to public health and quality of life. Here, we summarize the correlations between fine dust exposure and neurological disorders reported so far and make suggestions on the direction future research should take.

Oxidative stress and the cardiovascular effects of air pollution

Cardiovascular causes have been estimated to be responsible for more than two thirds of the considerable mortality attributed to air pollution. There is now a substantial body of research demonstrating that exposure to air pollution has many detrimental effects throughout the cardiovascular system. Multiple biological mechanisms are responsible, however, oxidative stress is a prominent observation at many levels of the cardiovascular impairment induced by pollutant exposure. This review provides an overview of the evidence that oxidative stress is a key pathway for the different cardiovascular actions of air pollution.

Out-of-Hospital Cardiac Arrests and Wildfire-Related Particulate Matter During 2015-2017 California Wildfires

Background

The natural cycle of large‐scale wildfires is accelerating, increasingly exposing both rural and populous urban areas to wildfire emissions. While respiratory health effects associated with wildfire smoke are well established, cardiovascular effects have been less clear.

Methods and Results

We examined the association between out‐of‐hospital cardiac arrest and wildfire smoke density (light, medium, heavy smoke) from the National Oceanic Atmospheric Association's Hazard Mapping System. Out‐of‐hospital cardiac arrest data were provided by the Cardiac Arrest Registry to Enhance Survival for 14 California counties, 2015–2017 (N=5336). We applied conditional logistic regression in a case‐crossover design using control days from 1, 2, 3, and 4 weeks before case date, at lag days 0 to 3. We stratified by pathogenesis, sex, age (19–34, 35–64, and ≥65 years), and socioeconomic status (census tract percent below poverty). Out‐of‐hospital cardiac arrest risk increased in association with heavy smoke across multiple lag days, strongest on lag day 2 (odds ratio, 1.70; 95% CI, 1.18–2.13). Risk in the lower socioeconomic status strata was elevated on medium and heavy days, although not statistically significant. Higher socioeconomic status strata had elevated odds ratios with heavy smoke but null results with light and medium smoke. Both sexes and age groups 35 years and older were impacted on days with heavy smoke.

Conclusions

Out‐of‐hospital cardiac arrests increased with wildfire smoke exposure, and lower socioeconomic status appeared to increase the risk. The future trajectory of wildfire, along with increasing vulnerability of the aging population, underscores the importance of formulating public health and clinical strategies to protect those most vulnerable.

A case-crossover analysis of the relationship of air pollution with out-of-hospital sudden unexpected death in Wake County, North Carolina (2013-2015)

Out-of-hospital sudden unexpected deaths are non-accidental deaths that occur without obvious underlying causes and may account for 10% of natural deaths before age 65. Short-term exposure to ambient air pollution is associated with all-cause (non-accidental) and cause-specific (e.g., cardiovascular) mortality, and with immediate exposures often yielding the highest magnitude risk estimates. Few studies have focused on short-term exposure to air pollution and sudden unexpected deaths. Using the University of North Carolina Sudden Unexpected Death in North Carolina population, we examine associations between short-term criteria air pollutant exposures with sudden unexpected deaths using a time-stratified case-crossover design, with data on criteria air pollutants from the Environmental Protection Agency's Air Quality System. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using conditional logistic regression with air pollutant exposures scaled to roughly inter-quartile ranges; models were adjusted for average temperature and relative humidity on event day and preceding 3 days. Potential for confounding by co-pollutants were examined in two pollutant models. ORs for PM_2.5 at lag day 1 were elevated (adjusted OR for 5 μg/m³ increase: 1.17 (0.98, 1.40)), and were robust to co-pollutant adjustment. Elevated odds were observed for SO₂ at lag day 0, and reduced odds for O₃ at lag day 0; however, these associations were somewhat attenuated toward the null (SO₂) or were not robust (O₃) to co-pollutant adjustment. This analysis in a racially and socioeconomically diverse cohort, with a more inclusive definition of sudden unexpected death than is typically employed offers evidence that PM_2.5 may be a clinically relevant trigger of sudden unexpected deaths in susceptible individuals.

Short-Term Effects of Ambient Air Pollution on ST-Elevation Myocardial Infarction Events: Are There Potentially Susceptible Groups?

Background: Air pollution exposure is associated with greater risk for cardiovascular events. This study aims to examine the effects of increased exposure to short-term air pollutants on ST-segment elevation myocardial infarction (STEMI) and determine the susceptible groups. Methods: Data on particulate matter PM2.5 and PM10 and other air pollutants, measured at each of the 11 air-quality monitoring stations in Kaohsiung City, were collected between 2011 and 2016. The medical records of non-trauma adult (>17 years) patients who had visited the emergency department (ED) with a typical electrocardiogram change of STEMI were extracted. A time-stratified and case-crossover study design was used to examine the relationship between air pollutants and daily ED visits for STEMI. Results: An interquartile range increment in PM2.5 on lag 0 was associated with an increment of 25.5% (95% confidence interval, 2.6%–53.4%) in the risk of STEMI ED visits. Men and persons with ≥3 risk factors (male sex, age, hypertension, diabetes, current smoker, dyslipidemia, history of myocardial infarction, and high body mass index) for myocardial infarction (MI) were more sensitive to the hazardous effects of PM2.5 (interaction: p = 0.039 and p = 0.018, respectively). The associations between PM10, NO2, and O3 and STEMI did not achieve statistical significance. Conclusion: PM2.5 may play an important role in STEMI events on the day of exposure in Kaohsiung. Men and persons with ≥3 risk factors of MI are more susceptible to the adverse effects of PM2.5 on STEMI.

Neuroendocrine Regulation of Air Pollution Health Effects: Emerging Insights

Air pollutant exposures are linked to cardiopulmonary diseases, diabetes, metabolic syndrome, neurobehavioral conditions, and reproductive abnormalities. Significant effort is invested in understanding how pollutants encountered by the lung might induce effects in distant organs. The role of circulating mediators has been predicted; however, their origin and identity have not been confirmed. New evidence has emerged which implicates the role of neuroendocrine sympathetic-adrenal-medullary (SAM) and hypothalamic-pituitary-adrenal (HPA) stress axes in mediating a wide array of systemic and pulmonary effects. Our recent studies using ozone exposure as a prototypical air pollutant demonstrate that increases in circulating adrenal-derived stress hormones (epinephrine and cortisol/corticosterone) contribute to lung injury/inflammation and metabolic effects in the liver, pancreas, adipose, and muscle tissues. When stress hormones are depleted by adrenalectomy in rats, most ozone effects including lung injury/inflammation are diminished. Animals treated with antagonists for adrenergic and glucocorticoid receptors show inhibition of the pulmonary and systemic effects of ozone, whereas treatment with agonists restore and exacerbate the ozone-induced injury/inflammation phenotype, implying the role of neuroendocrine activation. The neuroendocrine system is critical for normal homeostasis and allostatic activation; however, chronic exposure to stressors may lead to increases in allostatic load. The emerging mechanisms by which circulating mediators are released and are responsible for producing multiorgan effects of air pollutants insists upon a paradigm shift in the field of air pollution and health. Moreover, since these neuroendocrine responses are linked to both chemical and nonchemical stressors, the interactive influence of air pollutants, lifestyle, and environmental factors requires further study.

Pulmonary exposure to peat smoke extracts in rats decreases expiratory time and increases left heart end systolic volume

Exposure to wildland fire-related particulate matter (PM) causes adverse health outcomes. However, the impacts of specific biomass sources remain unclear. The purpose of this study was to investigate cardiopulmonary responses in rats following exposure to PM extracts collected from peat fire smoke. We hypothesized that peat smoke PM would dose-dependently alter cardiopulmonary function. Male Sprague-Dawley rats (n = 8/group) were exposed to 35 µg (Lo PM) or 350 µg (Hi PM) of peat smoke PM extracts suspended in saline, or saline alone (Vehicle) via oropharyngeal aspiration (OA). Ventilatory expiration times, measured in whole-body plethysmographs immediately after OA, were the lowest in Hi PM exposed subjects at 6 min into recovery (p = .01 vs. Lo PM, p = .08 vs. Vehicle) and resolved shortly afterwards. The next day, we evaluated cardiovascular function in the same subjects via cardiac ultrasound under isoflurane anesthesia. Compared to Vehicle, Hi PM had 45% higher end systolic volume (p = .03) and 17% higher pulmonary artery blood flow acceleration/ejection time ratios, and both endpoints expressed significant increasing linear trends by dose (p = .01 and .02, respectively). In addition, linear trend analyses across doses detected an increase for end diastolic volume and decreases for ejection fraction and fractional shortening. These data suggest that exposure to peat smoke constituents modulates regulation of ventricular ejection and filling volumes, which could be related to altered blood flow in the pulmonary circulation. Moreover, early pulmonary responses to peat smoke PM point to irritant/autonomic mechanisms as potential drivers of later cardiovascular responses.

Association between air pollution in the 2015 winter in South Korea and population size, car emissions, industrial activity, and fossil-fuel power plants: an ecological study

Background

Compared to 10 years ago, the ambient particulate matter 10 (PM₁₀) and carbon monoxide (CO) levels in South Korea have decreased. However, compared to many other OECD countries, these levels are still too high. Concentration of air pollutants such as PM₁₀ is especially higher during winter than during summer. The first step to rationally solving the air pollution problem in Korea is to identify the key air pollution sources during each season. This ecological study was performed to assess the association between the number of days the accepted PM₁₀ and CO thresholds were exceeded and the concentration of potential emission sources in winter season 2015.

Methods

An emission inventory of the PM₁₀ and CO emissions in the 232 administrative South Korean districts in January, 2015, and February, 2015 and December, 2015, and the population density, number of car registrations, number of car accidents, industrial power usage, and presence of a fossil-fuel power plant in each district was established on the basis of official web-page data from the government. For all emission source variables except power plants, the administrative districts were grouped into quartiles. Districts were also divided according to whether a power plant was present or not. Negative binomial regression was performed to assess the associations between the PM₁₀ and CO air pollution (defined as ≥100 g/m³ and ≥ 9 ppm, respectively) and the concentration of each emission source.

Results

Compared to the districts with the lowest population density, the districts with the third highest population density associated most strongly with air pollution. This was also observed for industrial power usage. Car accident number and car registration numbers showed a linear relationship with air pollution. Districts with power plants were significantly more likely to have air pollution than districts that lacked a plant.

Conclusions

Greater car numbers, industrial activity, and population density, and the presence of fossil-fuel plants associated with air pollution in the 2015 winter in South Korea. These data highlight the contaminant sources that could be targeted by interventions that aim to reduce air pollution, decrease the incidence of exposure, and limit the impact of pollution on human health.

Electronic supplementary material

The online version of this article (10.1186/s40557-018-0273-5) contains supplementary material, which is available to authorized users.

An Integrated Socio-Environmental Model of Health and Well-Being: a Conceptual Framework Exploring the Joint Contribution of Environmental and Social Exposures to Health and Disease Over the Life Span

PURPOSE OF THE REVIEW

Environmental and social determinants of health often co-occur, particularly among socially disadvantaged populations, yet because they are usually studied separately, their joint effects on health are likely underestimated. Building on converging bodies of literature, we delineate a conceptual framework to address these issues.

RECENT FINDINGS

Previous models provided a foundation for study in this area, and generated research pointing to additional important issues. These include a stronger focus on biobehavioral pathways, both positive and adverse health outcomes, and intergenerational effects. To accommodate the expanded set of issues, we put forward the Integrated Socio-Environmental Model of Health and Well-Being (ISEM), which examines how social and environmental factors combine and potentially interact, via multi-factorial pathways, to affect health and well-being over the life span. We then provide applied examples including the study of how food environments affect dietary behavior. The ISEM provides a comprehensive, theoretically informed framework to guide future research on the joint contribution of social and environmental factors to health and well-being across the life span.

Health impacts quantification of ambient air pollutants using AirQ model approach in Hamadan, Iran

Iranian western cities, including Hamadan, have been experiencing Middle East Dust Storms (MEDS) phenomenon problems in recent years, so the air quality is getting worse every year in these cities. The aim of this study was to evaluate the human health impacts of criteria air pollutants including PM₁₀, PM_2.5, NO₂, SO₂, CO and O₃ on the citizens of Hamadan using AirQ model software 2.2.3. Considering the determined baseline incidence (BI) and relative risk (RR) rate, the attributable proportion (AP) of deaths due to cardiovascular and respiratory mortality attributed to PM_2.5, PM₁₀, O₃, NO₂, and CO pollutants was estimated to be 4.42%, 3.37%, 1.75%, 1.74% and 0.92% (95% CI) of the total mortality and the excess death cases were respectively estimated to be 131.9, 100.4, 52.1, 51.9 and 27.3 persons. In addition, cardiovascular mortality brings more contribution than respiratory mortality in total death number. The results of our study also showed that PM_2.5 poses the greatest health effects on the citizens. Analyzing the average seasonal concentrations of studied pollutants (PM₁₀, PM_2.5, and NO₂) and the mean seasonal temperature values revealed a positive linear correlation. Significant negative correlations were observed between the studied pollutants (PM₁₀, PM_2.5 and NO₂) and relative humidity, and between PM and wind speed. This study, therefore, provides additional data in decision-makings for the development of strategies for reduction of ambient air pollution which will result in improvements of air quality.

Thrombosis and systemic and cardiac oxidative stress and DNA damage induced by pulmonary exposure to diesel exhaust particles and the effect of nootkatone thereon

Adverse cardiovascular effects of particulate air pollution persist even at lower concentrations than those of the current air quality limit. Therefore, identification of safe and effective measures against particle-induced cardiovascular toxicity is needed. Nootkatone is a sesquiterpenoid in grapefruit with diverse bioactivities including anti-inflammatory and antioxidant effects. However, its protective effect on the cardiovascular injury induced by diesel exhaust particles (DEPs) has not been studied before. We assessed the possible protective effect of nootkatone (90 mg/kg) administered by gavage 1 h before intratracheal instillation of DEPs (30 μg/mouse). Twenty-four hours after the intratracheal administration of DEPs, various thrombotic and cardiac parameters were assessed. Nootkatone inhibited the prothrombotic effect induced by DEPs in pial arterioles and venules in vivo and platelet aggregation in whole blood in vitro. Also, nootkatone prevented the shortening of activated partial thromboplastin time and prothrombin time induced by DEPs. Nootkatone inhibited the increase of plasma concentration of fibrinogen, plasminogen activator inhibitor-1, interleukin-6, and lipid peroxidation induced by DEPs. Immunohistochemically, hearts showed an analogous increase in glutathione and nuclear factor erythroid-derived 2-like 2 expression by cardiac myocytes and endothelial cells after DEP exposure, and these effects were enhanced in mice treated with nootkatone + DEPs. Likewise, heme oxygenase-1 was increased in mice treated with nootkatone + DEPs compared with those treated with DEPs or nootkatone + saline. The DNA damage caused by DEPs was prevented by nootkatoone pretreatment. In conclusion, nootkatoone alleviates DEP-induced thrombogenicity and systemic and cardiac oxidative stress and DNA damage, at least partly, through nuclear factor erythroid-derived 2-like 2 and heme oxygenase-1 activation. NEW & NOTEWORTHY Nootkatoone, a sesquiterpenoid found in grapefruit, alleviates the thrombogenicity and systemic and cardiac oxidative stress and DNA damage in mice exposed to diesel exhaust particles. Nootkatone-induced boosting of nuclear factor erythroid-derived 2-like 2 and heme oxygenase-1 levels in the heart of mice exposed to diesel exhaust particles suggests that its protective effect is, at least partly, mediated through nuclear factor erythroid-derived 2-like 2 and heme oxygenase-1 activation.

Long-term associations of morbidity with air pollution: A catalog and synthesis

I searched the National Institutes of Health MEDLINE database through January 2017 for long-term studies of morbidity and air pollution and cataloged them with respect to cardiovascular, respiratory, cancer, diabetes, hospitalization, neurological, and pregnancy-birth endpoints. The catalog is presented as an online appendix. Associations with PM_2.5 (particulate matter with an aerodynamic diameter <2.5 μm), PM₁₀ (PM with an aerodynamic diameter <10 μm), and nitrogen dioxide (NO₂) were evaluated most frequently among the 417 ambient air quality studies identified. Associations with total suspended particles (TSP), carbon, ozone, sulfur, vehicular traffic, radon, and indoor air quality were also reported. I evaluated each study in terms of pollutant significance (yes, no), duration of exposure, and publication date. I found statistically significant pollutant relationships (P < 0.05) in 224 studies; 220 studies indicated adverse effects. Among 795 individual pollutant effect estimates, 396 are statistically significant. Pollutant associations with cardiovascular indicators, lung function, respiratory symptoms, and low birth weight are more likely to be significant than with disease incidence, heart attacks, diabetes, or neurological endpoints. Elemental carbon (EC), traffic, and PM_2.5 are most likely to be significant for cardiovascular outcomes; TSP, EC, and ozone (O₃) for respiratory outcomes; NO₂ for neurological outcomes; and PM₁₀ for birth/pregnancy outcomes. Durations of exposure range from 60 days to 35 yr, but I found no consistent relationships with the likelihood of statistical significance. Respiratory studies began ca. 1975; studies of diabetes, cardiovascular, and neurological effects increased after about 2005. I found 72 studies of occupational air pollution exposures; 40 reported statistically significant adverse health effects, especially for respiratory conditions. I conclude that the aggregate of these studies supports the existence of nonlethal physiological effects of various pollutants, more so for non-life-threatening endpoints and for noncriteria pollutants (TSP, EC, PM_2.5 metals). However, most studies were cross-sectional analyses over limited time spans with no consideration of lag or disease latency. Further longitudinal studies are thus needed to investigate the progress of disease incidence in association with air pollution exposure.

IMPLICATIONS

Relationships of air pollution with excess mortality are better known than with long-term antecedent morbidity. I cataloged 489 studies of cardiovascular, respiratory, cancer, and neurological effects, diabetes, and birth outcomes with respect to 12 air pollutants. About half of the studies reported statistically significant relationships, more frequently with noncriteria than with criteria pollutants. Indoor and cumulative exposures, coarse or ultrafine particles, and organic carbon were seldom considered. Significant relationships were more likely with less-severe endpoints such as blood pressure, lung function, or respiratory symptoms than with incidence of cancer, chronic obstructive pulmonary disease (COPD), heart failure, or diabetes. Most long-term studies are based on spatial relationships; longitudinal studies are needed to link the progression of pollution-related morbidity to mortality, especially for the cardiovascular system.

Ultrafine particulate matter exposure impairs vasorelaxant response in superoxide dismutase 2-deficient murine aortic rings

Studies have linked exposure to ultrafine particulate matter (PM) and adverse cardiovascular events. PM-induced oxidative stress is believed to be a key mechanism underlying observed adverse vascular effects. Advanced age is one factor known to decrease antioxidant defenses and confer susceptibility to the detrimental vascular effects seen following PM exposure. The present study was designed to investigate the vasomotor responses following ultrafine PM exposure in wild type (WT) and superoxide dismutase 2-deficient (SOD2^+/-) mice that possess decreased antioxidant defense. Thoracic aortic rings isolated from young and aged WT and SOD2^+/- mice were exposed to ultrafine PM in a tissue bath system. Aortic rings were then constricted with increasing concentrations of phenylephrine, followed by relaxation with rising amounts of nitroglycerin (NTG). Data demonstrated that ultrafine PM decreased the relaxation response in both young WT and young SOD2^+/- mouse aortas, and relaxation was significantly reduced in young SOD2^+/- compared to WT mice. Ultrafine PM significantly diminished the NTG-induced relaxation response in aged compared to young mouse aortas. After ultrafine PM exposure, the relaxation response did not differ markedly between aged WT and aged SOD2^+/- mice. Data demonstrated that the greater vascular effect in aortic rings in aged mice ex vivo after ultrafine PM exposure may be attributed to ultrafine PM-induced oxidative stress and loss of antioxidant defenses in aged vascular tissue. Consistent with this conclusion is the attenuation of NTG-induced relaxation response in young SOD2^+/- mice.

ABBREVIATIONS

H₂O₂: hydrogen peroxide; NTG: nitroglycerin; PAH: polycyclic aromatic hydrocarbons; PE: l-phenylephrine; PM: particulate matter; ROS: reactive oxygen species; SOD2: superoxide dismutase 2 deficient; WT: wild type.

Long-term residential road traffic noise and NO2 exposure in relation to risk of incident myocardial infarction - A Danish cohort study

BACKGROUND

Road traffic is a source of both air pollution and noise; two environmental hazards both found to increase the risk of ischemic heart disease. Given the high correlation between these pollutants, it is important to investigate combined effects, in relation to myocardial infarction (MI).

METHODS

Among 50,744 middle-aged Danes enrolled into the Diet, Cancer and Health cohort from 1993 to 97, we identified 2403 cases of incident MI during a median follow-up of 14.5 years. Present and historical residential addresses from 1987 to 2011 were found in national registries, and traffic noise (L_den) and air pollution (NO₂) were modelled for all addresses. Analyses were performed using Cox proportional hazard models.

RESULTS

Road traffic noise and NO₂ were both individually associated with a higher risk of MI, with hazard ratios of 1.14 (1.07-1.21) and 1.08 (1.03-1.12) per inter-quartile range higher 10-year mean of road traffic noise and NO₂, respectively. Mutual exposure adjustment reduced the association with 10-year NO₂ exposure (1.02 (0.96-1.08)), whereas the association with road traffic noise remained: 1.12 (1.03-1.21). For fatal incident MI, the pattern was similar, but the associations for both pollutants were stronger. In analyses of tertiles across both pollutants, the strongest effects were seen for combined medium/high exposure, especially for fatal MI's.

CONCLUSION

Both road traffic noise and NO₂ were associated with a higher risk of MI in single-pollutant models. In two-pollutant models, mainly noise was associated with MI. Combined exposure to both pollutants was associated with the highest risk.