Relationship between ambient black carbon and daily mortality in Tehran, Iran: a distributed lag nonlinear time series analysis

Association between ambient fine particulate matter constituents and mortality and morbidity of cardiovascular and respiratory diseases: A systematic review and meta-analysis

Existing studies have explored the associations between short-term or long-term exposures to PM2.5 constituents and mortality and morbidity outcomes related to all-causes, natural causes and the cardiopulmonary system, but the results are still inconclusive. To explore the associations between short-term and long-term exposures to ambient PM2.5 constituents with mortality and morbidity outcomes of all-cause, natural, cardiovascular and respiratory diseases. We comprehensively searched PubMed, Embase, Web of Science and Scopus electronic databases to identify studies until 28, August 2023. We estimated the pooled relative risk (RR) with 95 % confidence interval (CI) using random-effect models. Then we explored potential sources of heterogeneity across different studies by subgroup and meta-regression analysis. A total of 67 articles were included in the meta-analysis. We found that short-term exposures to PM2.5 carbon-containing constituents (black carbon and organic carbon) and metal iron showed the most consistent associations with the eight health outcomes among different PM2.5 constituents. Meanwhile, only long-term exposures to nitrate ions and silicon in PM2.5 showed significant positive associations with cardiovascular and natural mortality outcomes. Additionally, subgroup and meta-regression analyses highlight that geographical region and age group are primary sources of heterogeneity. The current meta-analysis reveals potential key PM2.5 constituents associated with elevated risk of mortality and morbidity of cardiovascular and respiratory diseases. Thus, greater attention should be directed toward establishing exposure limits for specific PM2.5 constituents to protect public health and alleviate the associated burden of diseases.

Black Carbon Air Pollution and Incident Mortality Among the Advance-Aged Adults in China: A Prospective Cohort Study

BACKGROUND

We aimed to assess associations between black carbon (BC) and nonaccidental mortality among advance-aged adults in China.

METHODS

We conducted a prospective cohort study in 22 provinces of Chinese Longitudinal Healthy Longevity Survey. We calculated concentrations of 3-year average BC, fine particulate matter (PM2.5), and other PM2.5 components (SO42-, NO3-, NH4+, and organic matter) at individual levels. We used Cox proportional hazards models to assess dose-response BC exposure on nonaccidental mortality, adjusted for total PM2.5, green space, temperature, humidity, and demographic covariates.

RESULTS

We studied 12 873 participants, with a median age of 88 years and 57.4% females. For a median follow-up of 4 years, we observed 7 426 mortality events. The mean 3-year average BC and total PM2.5 exposure concentrations were 3.49 and 66.97 μg/m3, respectively. An increase of 1 μg/m3 in BC was associated with a 39% increase in mortality risks (HR: 1.39, 95% CI: 1.36, 1.43), notably higher than the corresponding increase in mortality risks linked to total PM2.5 (HR: 1.003, 95% CI: 1.002, 1.004) in the adjusted model. The stratified analyses show that people living in rural areas, with lower social and leisure activity index, and lower physical activity, were at greater risk from BC exposure.

CONCLUSIONS

BC is a strong predictor of mortality, with a higher effect estimate compared with total PM2.5 and other PM2.5 components, particularly in rural populations. Although total PM2.5 has been a target indicator of clean air policy interventions, our results indicate that BC concentration should be routinely measured, reported, and studied to improve public health.

Effects of particulate matter (PM2.5) concentration and components on mortality in chronic kidney disease patients: a nationwide spatial-temporal analysis

Chronic kidney disease (CKD) is a major global public health issue and the leading cause of death in Thailand. This study investigated the spatial-temporal association between PM2.5 and its components (organic carbon, black carbon, dust, sulfate, and sea salt) and CKD mortality in Thailand from 2012 to 2021. The Modern-Era Retrospective analysis for Research and Application version 2 (MERRA-2), a NASA atmospheric satellite model, was assessed for the temporal data of PM2.5 concentration and aerosol components. Spatial resources of 77 provinces were integrated using the Geographical Information System (GIS). Multivariate Poisson regression and Bayesian inference analyses were conducted to explore the effects of PM2.5 on CKD mortality across the provinces. Our analysis included 718,686 CKD-related deaths, resulting in a mortality rate of 1107 cases per 100,000 population where was the highest rate in Northeast region. The average age of the deceased was 72.43 ± 13.10 years, with males comprising 50.46% of the cases. Adjusting for age, sex, underlying diseases, co-morbidities, CKD complications, replacement therapy, population density, and income, each 1 µg/m3 increase in PM2.5, black carbon, dust, sulfate, and organic carbon was significantly associated with increased CKD mortality across 77 provinces. Incidence rate ratios were 1.04 (95% CI 1.03-1.04) for PM2.5, 1.11 (95% CI 1.10-1.13) for black carbon, 1.24 (95% CI 1.22-1.25) for dust, 1.16 (95% CI 1.16-1.17) for sulfate, and 1.05 (95% CI 1.04-1.05) for organic carbon. These findings emphasize the significant impact of PM2.5 on CKD mortality and underscore the need for strategies to reduce PM emissions and manage CKD co-morbidities effectively.

Short and long-term association of exposure to ambient black carbon with all-cause and cause-specific mortality: A systematic review and meta-analysis

Black carbon (BC) is a product of incomplete or inefficient combustion and may be associated with a variety of adverse effects on human health. The objective of this study was to analyze the association between various mortalities and long-/short-term exposure to BC as an independent pollutant. In this systematic review, we searched 4 databases for original research in English up to 6^th October 2022, that investigated population-wide mortality due to BC exposure. We pooled mortality estimates and expressed them as relative risk (RR) per 10 μg/m³ increase in BC. We used a random-effect model to derive the pooled RRs. Of the 3186 studies identified, 29 articles met the eligibility criteria, including 18 long-term exposure studies and 11 short-term exposure studies. In the major meta-analysis and sensitivity analysis, positive associations were found between BC and total mortality and cause-specific disease mortalities. Among them, the short-term effects of BC on total mortality, cardiovascular disease mortality, respiratory disease mortality, and the long-term effects of BC on total mortality, ischemic heart disease mortality, respiratory disease mortality and lung cancer mortality were found to be statistically significant. The heterogeneity of the meta-analysis results was much lower for short-term studies than for long-term. Few studies were at a high risk of bias in any domain. The certainty of the evidence for most of the exposure-outcome pairs was moderate. Our study showed a significantly positive association between short-/long-term BC exposure and various mortalities. We speculate that BC has a higher adverse health effect on the respiratory system than on the cardiovascular system. This is different from the effect of PM_2.5. Therefore, more studies are needed to consider BC as a separate pollutant, and not just as a component of PM_2.5.

Is short-term and long-term exposure to black carbon associated with cardiovascular and respiratory diseases? A systematic review and meta-analysis based on evidence reliability

OBJECTIVE

Adverse health effects of fine particles (particulate matter_2.5) have been well documented by a series of studies. However, evidences on the impacts of black carbon (BC) or elemental carbon (EC) on health are limited. The objectives were (1) to explored the effects of BC and EC on cardiovascular and respiratory morbidity and mortality, and (2) to verified the reliability of the meta-analysis by drawing p value plots.

DESIGN

The systematic review and meta-analysis using adapted Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach and p value plots approach.

DATA SOURCES

PubMed, Embase and Web of Science were searched from inception to 19 July 2021.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Time series, case cross-over and cohort studies that evaluated the associations between BC/EC on cardiovascular or respiratory morbidity or mortality were included.

DATA EXTRACTION AND SYNTHESIS

Two reviewers independently selected studies, extracted data and assessed risk of bias. Outcomes were analysed via a random effects model and reported as relative risk (RR) with 95% CI. The certainty of evidences was assessed by adapted GRADE. The reliabilities of meta-analyses were analysed by p value plots.

RESULTS

Seventy studies met our inclusion criteria. (1) Short-term exposure to BC/EC was associated with 1.6% (95% CI 0.4% to 2.8%) increase in cardiovascular diseases per 1 µg/m³ in the elderly; (2) Long-term exposure to BC/EC was associated with 6.8% (95% CI 0.4% to 13.5%) increase in cardiovascular diseases and (3) The p value plot indicated that the association between BC/EC and respiratory diseases was consistent with randomness.

CONCLUSIONS

Both short-term and long-term exposures to BC/EC were related with cardiovascular diseases. However, the impact of BC/EC on respiratory diseases did not present consistent evidence and further investigations are required.

PROSPERO REGISTRATION NUMBER

CRD42020186244.