Indoor black carbon of outdoor origin and oxidative stress biomarkers in patients with chronic obstructive pulmonary disease

Differential effects of fine particulate matter constituents on acute coronary syndrome onset

Fine particulate matter has been linked with acute coronary syndrome. Nevertheless, the key constituents remain unclear. Here, we conduct a nationwide case-crossover study in China during 2015-2021 to quantify the associations between fine particulate matter constituents (organic matter, black carbon, nitrate, sulfate, and ammonium) and acute coronary syndrome, and to identify the critical contributors. Our findings reveal all five constituents are significantly associated with acute coronary syndrome onset. The magnitude of associations peaks on the concurrent day, attenuates thereafter, and becomes null at lag 2 day. The largest effects are observed for organic matter and black carbon, with each interquartile range increase in their concentrations corresponding to 2.15% and 2.03% increases in acute coronary syndrome onset, respectively. These two components also contribute most to the joint effects, accounting for 31% and 22%, respectively. Our findings highlight tailored clinical management and targeted control of carbonaceous components to protect cardiovascular health.

Effects of fine particulate matter mass and chemical components on oxidative DNA damage in human early placenta

The effects of chemical components of ambient fine particulate matter (PM2.5) on human early maternal-fetal interface are unknown. We estimated the associations of PM2.5 and component exposures with placental villi 8-hydroxy-2'-deoxyguanosine (8-OHdG) in 142 normal early pregnancy (NEP) and 142 early pregnancy loss (EPL) from December 2017 to December 2022. We used datasets accessed from the Tracking Air Pollution in China platform to estimate maternal daily PM2.5 and component exposures. Effect of average PM2.5 and component exposures during the post-conception period (i.e., from ovulation to villi collection) on the concentration of villi 8-OHdG were analyzed using multivariable linear regression models. Distributed lag and cumulative effects of PM2.5 and component exposures during the periovulatory period and within ten days before villi collection on villi 8-OHdG were analyzed using distributed lag non-linear models combined with multivariable linear regression models. Per interquartile range increase in average PM2.5, black carbon (BC), and organic matter (OM) exposures during the post-conception period increased villi 8-OHdG in all subjects (β = 34.48% [95% CI: 9.33%, 65.42%], β = 35.73% [95% CI: 9.08%, 68.89%], and β = 54.71% [95% CI: 21.56%, 96.91%], respectively), and in EPL (β = 63.37% [95% CI: 16.00%, 130.10%], β = 47.43% [95% CI: 4.30%, 108.39%], and β = 72.32% [95% CI: 18.20%, 151.21%], respectively), but not in NEP. Specific weekly lag effects of PM2.5, BC, and OM exposures during the periovulatory period increased villi 8-OHdG in all subjects. Ten-day cumulative and lag effects of PM2.5, BC, and OM increased villi 8-OHdG in all subjects and EPL, but not in NEP; and the effects of OM were robust after adjusting for BC, ammonium, nitrate, or sulfate in two-pollutant models. In conclusion, placental oxidative DNA damage in early pregnancy was associated with maternal exposure to PM2.5, especially its chemical components BC and OM.

Implications of DNA damage in chronic lung disease

DNA plays an indispensable role in ensuring the perpetuation of life and safeguarding the genetic stability of living organisms. The emergence of diseases linked to a wide spectrum of responses to DNA damage has garnered increasing attention within the scientific community. There is growing evidence that patterns of DNA damage response in the lungs are associated with the onset, progression, and treatment of chronic lung diseases such as chronic obstructive pulmonary disease (COPD), asthma, and bronchopulmonary dysplasia (BPD). Currently, some studies have analyzed the mechanisms by which environmental factors induce lung DNA damage. In this article, we summarize inducible factors of lung DNA damage, current indicators, and methods for diagnosing DNA damage in chronic lung diseases and explore repair mechanisms after DNA damage including nonhomologous end-joining and homology-directed repair end joining pathways. Additionally, drug treatments that may reduce DNA damage or promote repair after it occurs in the lungs are briefly described. In general, more accurate assessment of the degree of lung DNA damage caused by various factors is needed to further elucidate the mechanism of lung DNA damage and repair after damage, so as to search for potential therapeutic targets.

Urinary Metabolites of Polycyclic Aromatic Hydrocarbons of Rural Population in Northwestern China: Oxidative Stress and Health Risk Assessment

Polycyclic aromatic hydrocarbon (PAH) exposure is suspected to be linked to oxidative damage. Herein, ten PAH human exposure biomarkers [hydroxylated PAH metabolites (OH-PAHs)] and five oxidative stress biomarkers (OSBs) were detected in urine samples collected from participants living in a rural area (n = 181) in Northwestern China. The median molar concentration of ΣOH-PAHs in urine was 47.0 pmol mL-1. The 2-hydroxynaphthalene (2-OHNap; median: 2.21 ng mL-1) was the dominant OH-PAH. The risk assessment of PAH exposure found that hazard index (HI) values were <1, indicating that the PAH exposure of rural people in Jingyuan would not generate significant cumulative risks. Smokers (median: 0.033) obtained higher HI values than nonsmokers (median: 0.015, p < 0.01), suggesting that smokers face a higher health risk from PAH exposure than nonsmokers. Pearson correlation and multivariate linear regression analysis revealed that ΣOH-PAH concentrations were significant factors in increasing the oxidative damage to deoxyribonucleic acid (DNA) (8-hydroxy-2'-deoxyguanosine, 8-OHdG), ribonucleic acid (RNA) (8-oxo-7,8-dihydroguanine, 8-oxoGua), and protein (o, o'-dityrosine, diY) (p < 0.05). Among all PAH metabolites, only 1-hydroxypyrene (1-OHPyr) could positively affect the expression of all five OSBs (p < 0.05), suggesting that urinary 1-OHPyr might be a reliable biomarker for PAH exposure and a useful indicator for assessing the impacts of PAH exposure on oxidative stress. This study is focused on the relation between PAH exposure and oxidative damage and lays a foundation for the study of the health effect mechanism of PAHs.

A Long-Term Comparison between the AethLabs MA350 and Aerosol Magee Scientific AE33 Black Carbon Monitors in the Greater Salt Lake City Metropolitan Area

Black carbon (BC) or soot contains ultrafine combustion particles that are associated with a wide range of health impacts, leading to respiratory and cardiovascular diseases. Both long-term and short-term health impacts of BC have been documented, with even low-level exposures to BC resulting in negative health outcomes for vulnerable groups. Two aethalometers-AethLabs MA350 and Aerosol Magee Scientific AE33-were co-located at a Utah Division of Air Quality site in Bountiful, Utah for just under a year. The aethalometer comparison showed a close relationship between instruments for IR BC, Blue BC, and fossil fuel source-specific BC estimates. The biomass source-specific BC estimates were markedly different between instruments at the minute and hour scale but became more similar and perhaps less-affected by high-leverage outliers at the daily time scale. The greater inter-device difference for biomass BC may have been confounded by very low biomass-specific BC concentrations during the study period. These findings at a mountainous, high-elevation, Greater Salt Lake City Area site support previous study results and broaden the body of evidence validating the performance of the MA350.

Air pollution and oxidative stress in adults suffering from airway diseases. Insights from the Gene Environment Interactions in Respiratory Diseases (GEIRD) multi-case control study

Air pollution is a leading risk factor for global mortality and morbidity. Oxidative stress is a key mechanism underlying air-pollution-mediated health effects, especially in the pathogenesis/exacerbation of airway impairments. However, evidence lacks on subgroups at higher risk of developing more severe outcomes in response to air pollution. This multi-centre study aims to evaluate the association between air pollution and oxidative stress in healthy adults and in patients affected by airway diseases from the Italian GEIRD (Gene Environment Interactions in Respiratory Diseases) multi-case control study. Overall, 1841 adults (49 % females, 20-83 years) were included from four Italian centres: Pavia, Sassari, Turin, and Verona. Following a 2-stage screening process, we identified 1273 cases of asthma, chronic bronchitis, rhinitis, or COPD and 568 controls. Systemic oxidative stress was quantified by urinary 8-isoprostane and 8-OH-dG. Individual residential exposures to NO2, PM10, PM2.5, and O3 were derived using an innovative five-stage machine-learning-based approach. Linear mixed regression models tested the association between oxidative stress biomarkers and air pollution tertiles, adjusting by age, sex, BMI, smoking, education and season, with recruiting centres as random intercept. Only cases exhibited higher levels of log-transformed 8-isoprostane and 8-OH-dG in association with NO2 (β: 0.30 95 % CI: 0.08-0.52 and 0.20 95 % CI: 0.03-0.37), PM10 (0.34 95 % CI: 0.12-0.55 and 0.21 95 % CI: 0.05-0.37) and PM2.5 (0.27 95 % CI: 0.09-0.49 and 0.18 95 % CI: 0.02-0.34) as compared to the first tertile of exposure. No significant associations were observed for summer O3. Our findings suggest that exposure to air pollution may increase systemic oxidative stress levels in people suffering from airway diseases. This introduces a potential novel approach available for future epidemiological studies and Public Health for effective prevention strategies oriented at the quantification of early biological effects in susceptible people, whose additional risk level might be currently underrated. Air-pollution-mediated exacerbations, driven by oxidative stress, still deserve our attention.

Biomarkers of the relationship of particulate matter exposure with the progression of chronic respiratory diseases

A high level of particulate matter (PM) in air is correlated with the onset and development of chronic respiratory diseases. We conducted a systematic literature review, searching the MEDLINE, EMBASE, and Cochrane databases for studies of biomarkers of the effect of PM exposure on chronic respiratory diseases and the progression thereof. Thirty-eight articles on biomarkers of the progression of chronic respiratory diseases after exposure to PM were identified, four of which were eligible for review. Serum, sputum, urine, and exhaled breath condensate biomarkers of the effect of PM exposure on chronic obstructive pulmonary disease (COPD) and asthma had a variety of underlying mechanisms. We summarized the functions of biomarkers linked to COPD and asthma and their biological plausibility. We identified few biomarkers of PM exposure-related progression of chronic respiratory diseases. The included studies were restricted to those on biomarkers of the relationship of PM exposure with the progression of chronic respiratory diseases. The predictive power of biomarkers of the effect of PM exposure on chronic respiratory diseases varies according to the functions of the biomarkers.

Radon decay product particle radioactivity and oxidative stress biomarkers in patients with COPD

Radon decay products include α-radiation emitting radionuclides that attach to airborne particles that have potential to promote oxidative tissue damage after inhalation. To assess associations between α-particle radioactivity (α-PR) with urinary biomarkers of oxidative tissue damage, 140 patients with chronic obstructive pulmonary disease (COPD) had up to four 1-week seasonal assessments (N = 413) of indoor (home) and ambient (central site) PM2.5 and black carbon (BC). Following environmental sampling, urine samples were analyzed for total and free malondialdehyde (MDA), biomarkers of lipid oxidation, and 8-hydroxyl-2'-deoxyguanosine (8-OHdG), a biomarker of DNA oxidative damage. Particle radioactivity was measured as α-activity on PM2.5 filter samples. Linear mixed-effects regression models adjusted for urinary creatinine and other personal characteristics were used to assess associations. Indoor α-PR was associated with an increase in 8-OhdG (8.53%; 95% CI: 3.12, 14.23); total MDA (5.59%; 95% CI: 0.20, 11.71); and free MDA (2.17%; 95% CI: 2.75, 7.35) per interquartile range (IQR) of α-PR [median 1.25 mBq/m3; IQR 0.64], similar adjusting for PM2.5 or BC. The ratio of indoor/ambient α-PR was positively associated with each biomarker and associations with ambient α-PR were positive but weaker than with indoor concentrations. These findings are consistent with a contribution of radon decay products as measured by α-PR to oxidative stress in patients with COPD, with a greater contribution of indoor radon decay products.

Indoor (residential) and ambient particulate matter associations with urinary oxidative stress biomarkers in a COPD cohort

OBJECTIVES

Oxidative stress contributes to chronic obstructive pulmonary disease (COPD) pathophysiology. Associations between indoor (residential) exposure to particulate matter ≤2.5 μm in diameter (PM2.5) and one of its components, black carbon (BC), and oxidative stress are ill-defined.

METHODS

Between 2012 and 2017, 140 patients with COPD completed in-home air sampling over one week intervals, followed by collection of urine samples to measure oxidative stress biomarkers, malondialdehyde (MDA), a marker of lipid peroxidation, and 8-hydroxy-2' -deoxyguanosine (8-OHdG), a marker of oxidative DNA damage. Ambient (central site) BC and PM2.5 were measured, and the ratio of indoor/ambient sulfur in PM2.5, a surrogate for residential ventilation and particle infiltration, was used to estimate indoor BC and PM2.5 of outdoor origin. Mixed effects linear regression models with a participant-specific random intercept were used to assess associations with oxidative biomarkers, adjusting for personal characteristics.

RESULTS

There were positive associations (% increase per IQR; 95 % CI) of directly measured indoor BC with total MDA (6.96; 1.54, 12.69) and 8-OHdG (4.18; -0.67, 9.27), and similar associations with both indoor BC of outdoor origin and ambient BC. There were no associations with directly measured indoor PM2.5, but there were positive associations between indoor PM2.5 of outdoor origin and total MDA (5.40; -0.91, 12.11) and 8-OHdG (8.02; 2.14, 14.25).

CONCLUSIONS

In homes with few indoor combustion sources, directly measured indoor BC, estimates of indoor BC and PM2.5 of outdoor origin, and ambient BC, were positively associated with urinary biomarkers of oxidative stress. This suggests that the infiltration of particulate matter from outdoor sources, attributable to traffic and other sources of combustion, promotes oxidative stress in COPD patients.

Determinants of indoor carbonaceous aerosols in homes in the Northeast United States

BACKGROUND

Little is known about sources of residential exposure to carbonaceous aerosols, which include black carbon (BC), the elemental carbon core of combustion particles, and organic compounds from biomass combustion (delta carbon).

OBJECTIVE

Assess the impact of residential characteristics on indoor BC and delta carbon when known sources of combustion (e.g., smoking) are minimized.

METHODS

Between November 2012-December 2014, 125 subjects (129 homes) in Northeast USA were recruited and completed a residential characteristics questionnaire. Every 3 months, participants received an automated sampler to measure fine particulate matter (PM2.5) in their home during a weeklong period (N = 371 indoor air samples) and were also questioned about indoor exposures. The samples were analyzed using a transmissometer at 880 nm (reflecting BC) and at 370 nm. The difference between the two wavelengths estimates delta carbon. Outdoor BC and delta carbon were measured using a central site aethalometer.

RESULTS

Geometric mean indoor concentrations of BC and delta carbon (0.65 µg/m³ and 0.19 µg/m³, respectively), were greater than central site concentrations (0.53 µg/m³ and 0.02 µg/m³, respectively). Multivariable analysis showed that greater indoor concentrations of BC were associated with infrequent candle use, multi-family homes, winter season, lack of air conditioning, and central site BC. For delta carbon, greater indoor concentrations were associated with apartments, spring season, and central site concentrations.

SIGNIFICANCE

In addition to outdoor central site concentrations, factors related to the type of housing, season, and home exposures are associated with indoor exposure to carbonaceous aerosols. Recognition of these characteristics should enable greater understanding of indoor exposures and their sources.

Intense solar activity reduces urinary 6-sulfatoxymelatonin in patients with COPD

BACKGROUND

Little is known about the link between solar activity and variations in melatonin. In this study, we investigated if melatonin's major urinary metabolite, urinary 6-sulfatoxymelatonin (aMT6s), is lowest under periods of intense solar activity.

METHODS

We investigated associations between high-energy solar particle events [Coronal Mass Ejection (CME) mass, speed and energy] on creatinine-adjusted aMT6s (aMT6sr) concentrations in 140 patients with chronic obstructive pulmonary disease (COPD) using up to four seasonal urine samples (n = 440). Mixed effect models with a random intercept for each subject were used to estimate associations, including effect modification attributable to diabetes, obesity, and reduced pulmonary function.

RESULTS

Higher values of CME were associated with reduced aMT6sr concentrations, with stronger associations in patients with diabetes. An interquartile range (IQR) increase in natural log CMEspeed averaged through two days before urine collection was associated with a reduction of 9.3% aMT6sr (95%CI: - 17.1%, - 0.8%) in aMT6sr. There was a greater reduction in aMT6sr in patients with diabetes (- 24.5%; 95%CI: - 35.9%, - 11.6%). In patients without diabetes there was no meaningful association (- 2.2%; 95%CI: - 12%, 8.4%). There were similar associations with CMEenergy and CMEmass. There was no effect modification attributable to reduced pulmonary function or obesity.

CONCLUSIONS

This is the first study in patients with COPD to demonstrate strong detrimental impact of high-energy solar particle events on aMT6sr, with greater associations in patients with diabetes. Since melatonin is an anti-oxidant, it is possible that adverse effects of intense solar activity may be attributable to a reduction in circulating melatonin and that patients with both COPD and diabetes may be more susceptible.

Particle radioactivity from radon decay products and reduced pulmonary function among chronic obstructive pulmonary disease patients

BACKGROUND

Radon (222Rn) decay products can attach to particles in the air, be inhaled, and potentially cause airway damage.

RESEARCH QUESTION

Is short-term exposure to particle radioactivity (PR) attributable to radon decay products emitted from particulate matter ≤2.5 μm in diameter (PM2.5) associated with pulmonary function in chronic obstructive pulmonary disease (COPD) patients?

STUDY DESIGN AND METHODS

In this cohort study, 142 elderly, predominantly male patients with COPD from Eastern Massachusetts each had up to 4 one-week long seasonal assessments of indoor (home) and ambient (central site) PR and PM2.5 over the course of a year (467 assessments). Ambient and indoor PR were measured as α-activity on archived PM2.5 filter samples. Ratios of indoor/ambient PR were calculated, with higher ratios representing PR from an indoor source of radon decay. We also considered a measure of outside air infiltration that could dilute the concentrations of indoor radon decay products, the indoor/ambient ratio of sulfur concentrations in PM2.5 filter samples. Spirometry pre- and post-bronchodilator (BD) forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) were conducted following sampling. Generalized additive mixed models were adjusted for meteorologic variables, seasonality, and individual-level determinants of pulmonary function. We additionally adjusted for indoor PM2.5 and black carbon (BC).

RESULTS

PR exposure metrics indicating radon decay product exposure from an indoor source were associated with a reduction in FEV1 and FVC. Patients in homes with high indoor PR (≥median) and low air infiltration (

INTERPRETATION

Our findings raise concern about the harmful effects of PR exposures attributable to residential radon on pulmonary function in patients with COPD.

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Key Words

• Chronic obstructive pulmonary disease
• Particle radioactivity
• Pulmonary function
• Radiation
• Radon
• Spirometry

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MESH Headings

• Humans
• Male
• Aged
• Female
• Radon Daughters
• Air Pollutants/analysis
• Radioactivity
• Cohort Studies
• Particulate Matter/analysis
• Pulmonary Disease, Chronic Obstructive
• Soot
• Radon
• Environmental Exposure/analysis

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Grants

• R01 ES019853 NIEHS NIH HHS
• R21 ES029637 NIEHS NIH HHS

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Affiliation(s)

Veronica A Wang Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA
Petros Koutrakis Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA
Longxiang Li Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA
Man Liu Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA
Carolina L Z Vieira Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA
Brent A Coull Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, USA
Edward F Maher Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA
Choong-Min Kang Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA
Eric Garshick Pulmonary, Allergy, Sleep and Critical Care Medicine Section, Veterans Affairs Boston Healthcare System, Boston, MA, USA; Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA.

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The Effects and Pathogenesis of PM2.5 and Its Components on Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD), a heterogeneous disease, is the leading cause of death worldwide. In recent years, air pollution, especially particulate matter (PM), has been widely studied as a contributing factor to COPD. As an essential component of PM, PM2.5 is associated with COPD prevalence, morbidity, and acute exacerbations. However, the specific pathogenic mechanisms were still unclear and deserve further research. The diversity and complexity of PM2.5 components make it challenging to get its accurate effects and mechanisms for COPD. It has been determined that the most toxic PM2.5 components are metals, polycyclic aromatic hydrocarbons (PAHs), carbonaceous particles (CPs), and other organic compounds. PM2.5-induced cytokine release and oxidative stress are the main mechanisms reported leading to COPD. Nonnegligibly, the microorganism in PM 2.5 may directly cause mononuclear inflammation or break the microorganism balance contributing to the development and exacerbation of COPD. This review focuses on the pathophysiology and consequences of PM2.5 and its components on COPD.

Cold Climate Impact on Air-Pollution-Related Health Outcomes: A Scoping Review

In cold temperatures, vehicles idle more, have high cold-start emissions including greenhouse gases, and have less effective exhaust filtration systems, which can cause up to ten-fold more harmful vehicular emissions. Only a few vehicle technologies have been tested for emissions below -7 °C (20 °F). Four-hundred-million people living in cities with sub-zero temperatures may be impacted. We conducted a scoping review to identify the existing knowledge about air-pollution-related health outcomes in a cold climate, and pinpoint any research gaps. Of 1019 papers identified, 76 were selected for review. The papers described short-term health impacts associated with air pollutants. However, most papers removed the possible direct effect of temperature on pollution and health by adjusting for temperature. Only eight papers formally explored the modifying effect of temperatures. Five studies identified how extreme cold and warm temperatures aggravated mortality/morbidity associated with ozone, particles, and carbon-monoxide. The other three found no health associations with tested pollutants and temperature. Additionally, in most papers, emissions could not be attributed solely to traffic. In conclusion, evidence on the relationship between cold temperatures, traffic-related pollution, and related health outcomes is lacking. Therefore, targeted research is required to guide vehicle regulations, assess extreme weather-related risks in the context of climate change, and inform public health interventions.

Effects of particulate matter gamma radiation on oxidative stress biomarkers in COPD patients

Inhalation of particulate matter (PM) radioactivity is an important pathway of ionizing radiation exposure. We investigated the associations between short-term exposures to PM gamma radioactivity with oxidative stress in COPD patients. Urinary concentrations of 8-hydroxy-2'-deoxyguanosine (8-OHdG) and malondialdehyde (MDA) of 81 COPD patients from Eastern Massachusetts were measured 1-4 times during 2012-2014. Daily ambient and indoor PM gamma activities (gamma-3 through gamma-9) were calculated based on EPA RadNet data and indoor-outdoor infiltration ratios. Linear mixed-effects models were used to examine the associations between biomarkers with PM gamma activities for moving averages from urine collection day to 7 days before. Our results indicate that ambient and indoor PM gamma activities were positively associated with 8-OHdG, with stronger effects for exposure windows closer to urine collection day. For per interquartile range increase in indoor PM gamma activities averaged over urine collection day and 1 day before, 8-OHdG increased from 3.41% (95% CI: -0.88, 7.88) to 8.87% (95% CI: 2.98, 15.1), adjusted for indoor black carbon. For MDA, the timing of greatest effects across the exposure week varied but was nearly all positive. These findings provide insight into the toxigenic properties associated with PM radioactivity and suggest that these exposures promote systemic oxidative stress.

Short-term differences in cardiac function following controlled exposure to cookstove air pollution: The subclinical tests on volunteers exposed to smoke (STOVES) study

BACKGROUND

Exposure to household air pollution from solid fuel combustion for cooking and heating is an important risk factor for premature death and disability worldwide. Current evidence supports an association of ambient air pollution with cardiovascular disease but is limited for household air pollution and for cardiac function. Controlled exposure studies can complement evidence provided by field studies.

OBJECTIVES

To investigate effects of short-term, controlled exposures to emissions from five cookstoves on measures of cardiac function.

METHODS

Forty-eight healthy adults (46% female; 20-36 years) participated in six, 2-h exposures ('treatments'), including emissions from five cookstoves and a filtered-air control. Target fine particulate matter (PM2.5) exposure-concentrations per treatment were: control, 0 µg/m3; liquefied petroleum gas, 10 µg/m3; gasifier, 35 µg/m3; fan rocket, 100 µg/m3; rocket elbow, 250 µg/m3; and three stone fire, 500 µg/m3. Participants were treated in a set (pre-randomized) sequence as groups of 4 to minimize order bias and time-varying confounders. Heart rate variability (HRV) and cardiac repolarization metrics were calculated as 5-min means immediately and at 3 h following treatment, for analysis in linear mixed-effects models comparing cookstove to control.

RESULTS

Short-term differences in SDNN (standard deviation of duration of all NN intervals) and VLF (very-low frequency power) existed for several cookstoves compared to control. While all cookstoves compared to control followed a similar trend for SDNN, the greatest effect was seen immediately following three stone fire (β = -0.13 ms {%}; 95% confidence interval = -0.22, -0.03%), which reversed in direction at 3 h (0.03%; -0.06, 0.13%). VLF results were similar in direction and timing to SDNN; however, other HRV or cardiac repolarization results were not similar to those for SDNN.

DISCUSSION

We observed some evidence of short-term, effects on HRV immediately following cookstove treatments compared to control. Our results suggest that cookstoves with lower PM2.5 emissions are potentially capable of affecting cardiac function, similar to stoves emitting higher PM2.5 emissions.

Urinary mutagenicity and oxidative status of wildland firefighters working at prescribed burns in a Midwestern US forest

OBJECTIVE

Wildland firefighters (WLFFs) experience repeated exposures to wildland fire smoke (WFS). However, studies about WLFFs remain regionally limited. The objective of this study was to assess the effect of WFS exposure on urinary mutagenicity and cell oxidation among WLFFs who work at prescribed burns in the Midwestern USA.

METHODS

A total of 120 spot urine samples was collected from 19 firefighters right before (pre-shift), immediately after (post-shift), and the morning (next-morning) following work shifts on prescribed burn days (burn days) and regular workdays (non-burn days). The levels of urinary mutagenicity, 8-isoprostane, malondialdehyde and oxidised guanine species (Ox-GS) were measured. Linear mixed-effect models were used to determine the difference of cross-shift changes in the concentrations of urinary biomarkers.

RESULTS

Post-shift levels of creatinine-corrected urinary mutagenicity and 8-isoprostane were non-significantly higher than pre-shift levels (1.16× and 1.64×; p=0.09 and 0.07) on burn days. Creatinine-corrected Ox-GS levels increased significantly in next-morning samples following WFS exposure (1.62×, p=0.03). A significant difference in cross-shift changes between burn and non-burn days was observed in 8-isoprostane (2.64×, p=0.03) and Ox-GS (3.00×, p=0.02). WLFFs who contained the fire (performed holding tasks) had a higher pre-morning to next-morning change in urinary mutagenicity compared with those who were lighting fires during the prescribed burns (1.56×, p=0.03).

CONCLUSIONS

Compared with the other regions, WLFFs who worked in Midwestern forests had an elevated urinary mutagenicity and systemic oxidative changes associated with WFS exposure at prescribed burns.

Schisandra A ameliorates cigarette smoke extract and lipopolysaccharide-induced oxidative stress in lung epithelial cells

Background

The previous studies reported the antioxidant and anti-inflammatory properties of Schisandrin A (Sch A). This study aimed to investigate the ability of Sch A to protect against lung oxidative stress induced by the combination of cigarette smoke extract and lipopolysaccharide (LPS) in an in vitro model of chronic obstructive pulmonary disease (COPD).

Methods

The cell viability was determined by using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Colorimetry was used to detect the changes in antioxidant markers. Quantitative real-time polymerase chain reaction (RT-PCR) was used to examine the mRNA levels of interleukin-8 (IL-8) and heme oxygenase-1 (HO-1). The levels of IL-8 and HO-1 in the supernatant were determined by enzyme-linked immunosorbent assay, and Western blot analysis was performed to measure the phosphorylation and protein expression levels of nuclear factor-κB.

Results

Sch A inhibited the excessive proliferation of pulmonary epithelial cells, decreased malondialdehyde content, and increased the expression levels of superoxide dismutase and glutathione after the combined treatment of cigarette smoke extract and LPS. Also, Sch A downregulated the expression of IL-8 and upregulated the expression of HO-1 mRNA in lung epithelial cells and cell supernatants, and resulted in the downregulation of the protein expression level of phosphorylated nuclear factor-κB.

Conclusions

Sch A inhibited the oxidative stress of lung epithelial cells induced by the combination of cigarette smoke extract and LPS. Sch A may be a potential therapeutic medication for COPD.

LC-MS Quantification of Malondialdehyde-Dansylhydrazine Derivatives in Urine and Serum Samples

We developed a robust analytical method for quantification of malondialdehyde (MDA) in urine and serum samples using dansylhydrazine (DH) as a derivatizing reagent. The derivatization procedure was partially carried out using an autosampler injection program to minimize errors associated with the low-volume addition of reagents and was optimized to yield a stable hydrazone derivative of MDA and its labeled d2-MDA analogue. The target MDA-DH derivatives were separated on an Agilent Zorbax Eclipse Plus Phenyl-Hexyl (3.0 × 100 mm, 3.5 μm) column. The mass-to-charge ratios of the target derivatives [(M+H)+ of 302 and 304 for MDA-DH and d2-MDA-DH, respectively] were analyzed in single ion monitoring mode using a single quadrupole mass spectrometer operated under positive electrospray ionization. The method limits of quantification were 5.63 nM (or 0.405 ng/mL) for urine analysis and 5.68 nM (or 0.409 ng/mL) for serum analysis. The quantification range for urine analysis was 5.63-500 nM (0.405-36.0 ng/mL) while the quantification range for serum analysis was 5.68-341 nM (0.409-24.6 ng/mL). The method showed good relative recoveries (98-103%), good accuracies (92-98%), and acceptable precisions (relative standard deviations 1.8-7.3% for inter-day precision; 1.8-6.1% for intra-day precision) as observed from the repeat analysis of quality control samples prepared at different concentrations. The method was used to measure MDA in individual urine samples (n = 287) and de-identified archived serum samples (n = 22) to assess the overall performance of the method. The results demonstrated that our method is capable of measuring urinary and serum levels of MDA, allowing its future application in epidemiologic investigations.

Residential wood stove use and indoor exposure to PM2.5 and its components in Northern New England

BACKGROUND

Residential wood stove use has become more prevalent in high-income countries, but only limited data exist on indoor exposure to PM_2.5 and its components.

METHODS

From 2014 to 2016, we collected 7-day indoor air samples in 137 homes of pregnant women in Northern New England, using a micro-environmental monitor. We examined associations of wood stove use with PM_2.5 mass and its components [black carbon (BC), organic and elemental carbon and their fractions, and trace elements], adjusted for sampling season, community wood stove use, and indoor activities. We examined impact of stove age, EPA-certification, and wood moisture on indoor pollutants.

RESULTS

Median (IQR) household PM_2.5 was 6.65 (5.02) µg/m³ and BC was 0.23 (0.20) µg/m³. Thirty percent of homes used a wood stove during monitoring. In homes with versus without a stove, PM_2.5 was 20.6% higher [although 95% confidence intervals (-10.6, 62.6) included the null] and BC was 61.5% higher (95% CI: 11.6, 133.6). Elemental carbon (total and fractions 3 and 4), potassium, calcium, and chloride were also higher in homes with a stove. Older stoves, non-EPA-certified stoves, and wet or mixed (versus dry) wood were associated with higher pollutant concentrations, especially BC.

CONCLUSIONS

Homes with wood stoves, particularly those that were older and non-EPA-certified or burning wet wood had higher concentrations of indoor air combustion-related pollutants.

Short-term effects of particle gamma radiation activities on pulmonary function in COPD patients

BACKGROUND

It is not known whether environmental gamma radiation measured in US cities has detectable adverse health effects. We assessed whether short-term exposure to gamma radiation emitted from ambient air particles [gamma particle activity (PRγ)] is associated with reduced pulmonary function in chronic obstructive pulmonary disease (COPD) patients.

OBJECTIVE

We hypothesize that the inhalation of gamma radiation emitted from ambient air particles may be associated with reduced pulmonary function in individuals with COPD.

METHODS

In 125 patients with COPD from Eastern Massachusetts who had up to 4 seasonal one-week assessments of particulate matter ≤2.5 μm (PM_2.5), black carbon (BC), and sulfur followed by spirometry. The US EPA continuously monitors ambient gamma (γ) radiation including γ released from radionuclides attached to particulate matter that is recorded as 9 γ-energy spectra classes (i = 3-9) in counts per minute (CPMγ) in the Boston area (USA). We analyzed the associations between ambient and indoor PRγi (up to one week) and pre and post-bronchodilator (BD) forced expiratory volume in 1 s (FEV₁) and with forced vital capacity (FVC) using mixed-effects regression models. We estimated indoor PRγi using the ratio of the indoor-to-outdoor sulfur in PM_2.5 as a proxy for infiltration of ambient radionuclide-associated particles.

RESULTS

Overall, exposures to ambient and indoor PRγi were associated with a similar decrease in pre- and post-BD FEV₁ and FVC. For example, ambient PRγ₃ exposure averaged from the day of pulmonary function testing through the previous 3 days [IQR of 55.1 counts per minute (CPMγ)] was associated with a decrease in pre-BD FEV₁ of 21.0 ml (95%CI: -38.5 to -3.0 ml; p < 0.01) and pre-BD FVC of 27.5 ml [95% confidence interval (CI): -50.7 to -5.0 ml; p < 0.01] with similar effects adjusting for indoor and outdoor BC and PM_2.5.

CONCLUSION

Our results show that short-term ambient and indoor exposures to environmental gamma radiation associated with particulate matter are associated with reduced pre- and post-BD pulmonary function in patients with COPD.

Synthesis of Harvard Environmental Protection Agency (EPA) Center studies on traffic-related particulate pollution and cardiovascular outcomes in the Greater Boston Area

The association between particulate pollution and cardiovascular morbidity and mortality is well established. While the cardiovascular effects of nationally regulated criteria pollutants (e.g., fine particulate matter [PM_2.5] and nitrogen dioxide) have been well documented, there are fewer studies on particulate pollutants that are more specific for traffic, such as black carbon (BC) and particle number (PN). In this paper, we synthesized studies conducted in the Greater Boston Area on cardiovascular health effects of traffic exposure, specifically defined by BC or PN exposure or proximity to major roadways. Large cohort studies demonstrate that exposure to traffic-related particles adversely affect cardiac autonomic function, increase systemic cytokine-mediated inflammation and pro-thrombotic activity, and elevate the risk of hypertension and ischemic stroke. Key patterns emerged when directly comparing studies with overlapping exposure metrics and population cohorts. Most notably, cardiovascular risk estimates of PN and BC exposures were larger in magnitude or more often statistically significant compared to those of PM_2.5 exposures. Across multiple exposure metrics (e.g., short-term vs. long-term; observed vs. modeled) and different population cohorts (e.g., elderly, individuals with co-morbidities, young healthy individuals), there is compelling evidence that BC and PN represent traffic-related particles that are especially harmful to cardiovascular health. Further research is needed to validate these findings in other geographic locations, characterize exposure errors associated with using monitored and modeled traffic pollutant levels, and elucidate pathophysiological mechanisms underlying the cardiovascular effects of traffic-related particulate pollutants. Implications: Traffic emissions are an important source of particles harmful to cardiovascular health. Traffic-related particles, specifically BC and PN, adversely affect cardiac autonomic function, increase systemic inflammation and thrombotic activity, elevate BP, and increase the risk of ischemic stroke. There is evidence that BC and PN are associated with greater cardiovascular risk compared to PM_2.5. Further research is needed to elucidate other health effects of traffic-related particles and assess the feasibility of regulating BC and PN or their regional and local sources.

Short-Term Effects of Carbonaceous Components in PM2.5 on Pulmonary Function: A Panel Study of 37 Chinese Healthy Adults

OBJECTIVES

To explore the health effects of indoor/outdoor carbonaceous compositions in PM_2.5 on pulmonary function among healthy students living in the local university campus.

METHODS

Daily peak expiratory flow (PEF) and forced expiratory volume in 1 second (FEV₁) were measured among 37 healthy students in the morning and evening for four two-week periods. Concurrent concentrations of indoor and outdoor PM_2.5 (particulate matter with an aerodynamic diameter ≤ 2.5μm), carbonaceous components in PM_2.5, ambient temperature, and relative humidity in the study area were also obtained. Mixed-effects model was applied to evaluate the associations between carbonaceous components and lung function. Different lags for the carbonaceous components were investigated.

RESULTS

In single-pollutant model, a 10 μg/m³ increase of indoor and outdoor EC (elemental carbon) associated with -3.93 (95%CI: -6.89, -0.97) L/min and -3.21 (95%CI: -5.67, -0.75) L/min change in evening PEF at lag 0 day, respectively. Also, a 10 μg/m³ increase of indoor and outdoor POC (primary organic carbon) concentration was significantly associated with -5.82 (95%CI: -10.82, -0.81) L/min and -7.32 (95%CI: -12.93, -1.71) L/min change of evening PEF at lag 0 day. After adjusting total mass of PM_2.5, indoor EC consistently had a significant adverse impact on evening PEF and FEV₁ at lag3 day and a cumulative effect at lag0-3 day.

CONCLUSIONS

This study suggests that carbonaceous components in PM_2.5 indeed have impacts on pulmonary function among healthy young adults especially on evening PEF. Thus, the local mitigation strategies on pollution are needed.

Nanosized carbon black exposure induces neural injury: effects on nicotinamide adenine dinucleotide phosphate oxidases and endoplasmic reticulum stress

Carbon black in ambient air is believed to be the cause of many diseases; however, its potential neural toxicity and the underlying mechanisms remain poorly understood. The present study is to evaluate the toxic effects of carbon black nanoparticles, Printex 90, on the neural cell line PC-12. The study revealed that Printex 90 treatment significantly decreased cell viability, accompanied by an enormous increase in reactive oxygen species generation and a decrease in ATP. Additionally, NOX2 and NOX4, 4-hydroxynonenal, endoplasmic reticulum (ER) stress marker proteins (IRE-1α, ATF-6, GRP78, PERK and the downstream target protein CHOP) and antioxidative enzymes (glutathione and superoxide dismutase) were evaluated. It showed that Printex 90 significantly upregulated 4-hydroxynonenal, NOX2 and NOX4 expression, and the levels, or activity, of glutathione and superoxide dismutase, were markedly reduced. For the ER stress-associated proteins, Printex 90 induced a significant increase of IRE-1α, ATF-6, GRP78, p-PERK and CHOP expression. Collectively, these results demonstrate that NOX and ER stress are involved in Printex 90-mediated neural damage. Therefore, decreased ER stress and NOX-derived reactive oxygen species generation may provide compensatory protective effects and attenuate Printex 90-induced neural injury.

Indoor black carbon and biomarkers of systemic inflammation and endothelial activation in COPD patients

RATIONALE

Evidence linking traffic-related particle exposure to systemic effects in chronic obstructive lung disease (COPD) patients is limited.

OBJECTIVES

Assess relationships between indoor black carbon (BC), a tracer of traffic-related particles, and plasma biomarkers of systemic inflammation and endothelial activation.

METHODS

BC was measured by reflectance in fine particle samples over a mean of 7.6 days in homes of 85 COPD patients up to 4 times seasonally over a year. After the completion of sampling, plasma C-reactive protein (CRP), interleukin-6 (IL-6), and soluble vascular adhesion molecule-1 (sVCAM-1) were measured. Current smokers and homes with major sources of BC were excluded; therefore, indoor BC was primarily a measure of infiltrated outdoor BC. Mixed effects regression models with a random intercept for each participant were used to assess BC effects at different times (1-9 days before phlebotomy) and in the multi-day sample.

RESULTS

Measured median BC was 0.19 µg/m³ (interquartile range, IQR=0.22 µg/m³). Adjusting for season, race, age, BMI, heart disease, diabetes, ambient temperature, relative humidity, a recent cold or similar illness, and blood draw time, there was a positive relationship between BC and CRP. The largest effect size was for BC averaged over the previous seven days (11.8% increase in CRP per IQR; 95%CI = 1.8-22.9). Effects were greatest among non-statin users and persons with diabetes. There were positive effects of BC on IL-6 only in non-statin users. There were no associations with sVCAM-1.

CONCLUSIONS

These results demonstrate exposure-response relationships between indoor BC with biomarkers of systemic inflammation in COPD patients, with stronger relationships in persons not using statins and with diabetes.

Relationship between free and total malondialdehyde, a well-established marker of oxidative stress, in various types of human biospecimens

BACKGROUND

Oxidative stress is involved in thoracic diseases and health responses to air pollution. Malondialdehyde (MDA) is a well-established marker of oxidative stress, but it may be present in unconjugated and conjugated forms. To our knowledge, no studies have conducted a systemic evaluation of both free MDA (unconjugated MDA) and total MDA (the sum of both unconjugated and conjugated MDA) across various types of human biospecimens.

METHODS

Free MDA and total MDA were simultaneously measured in a range of human biospecimens, including nasal fluid (N=158), saliva (N=158), exhaled breath condensate (N=40), serum (N=232), and urine (N=429). All samples were analyzed using an HPLC-fluorescence method with high sensitivity and specificity. Due to the right skewed distribution of free MDA and total MDA, we performed natural-log transformation before subsequent statistical analyses. The relationship between the natural log of free and total MDA was evaluated by R2 of simple linear regression. T test was used for comparisons of means between two groups. One-way analysis of variance was used in combination with Tukey's test to compare the natural log of the ratio of free MDA to total MDA across various types of biospecimens.

RESULTS

For exhaled breath condensate, serum, urine, nasal fluid and saliva samples, the R2 between free and total MDA were 0.61, 0.22, 0.59, 0.47 and 0.06, respectively; the medians of the free MDA to total MDA ratio were 48.1%, 17.4%, 9.8%, 5.1% and 3.0%, respectively; the free MDA to total MDA ratio in EBC > serum > urine > nasal fluid > saliva (P<0.001 for pairwise comparisons).

CONCLUSIONS

For exhaled breath condensate and urine samples, using either free or total MDA can provide information regarding the level of oxidative stress; however, that is not the case for serum, nasal fluid, and saliva given the low correlations between free and total MDA.