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

Abstract

Purpose The aim of the present study was to investigate the effect of short-term exposure to ambient black carbon (BC) on daily causespecific mortality, including mortality due to respiratory, cardiovascular, ischemic heart and cerebrovascular diseases in Tehran, Iran. Materials and methods Daily non-accidental death counts, meteorological data and hourly concentrations of air pollutants from 2014 to 2017 were collected in Tehran. A distributed lag non-linear model was used to assess the association between exposure to BC and daily mortality. ResultsThe mean daily BC concentration during the study period was 3.96 ± 1.19 µg/m 3 . The results indicated that BC was significantly associated with cardiovascular, ischemic heart disease, and cerebrovascular mortality, but not with respiratory mortality. In first model, each 10 µg/m 3 increase in at lag 3, lag 4 and lag 5 were associated with cardiovascular mortality in 16-65 year age group with the relative risks (RRs) of 1.17 (95 % CI: 1.02-1.33), 1.17 (95 % CI: 1.04-1.31) and 1.12 (95 % CI: 1.02-1.24), respectively. The highest mortality rate per 10 µg/m 3 increase in exposure was found for ischemic heart diseases with RR of 3.98 (95 % CI: 1.04-1.81, lag 01) for 16-65 age group. Cerebrovascular mortality was associated with 10 µg/m 3 increases in non-cumulative exposure with RR of 1.17 (95 % 1.009-1.35, lag 5) in the age group ≥ 65 years. In the second model for a 10 µg/m 3 increase in BC, cardiovascular mortality at specific lag days (5 and 6 days) in the age group ≤ 16 years were associated with RR of 1.34 (95 % CI 1.08-1.66) and 1.35(95 % CI 1.02-1.77), respectively. Conclusions This study in Tehran found significant effects of BC exposure on daily mortality for cardiovascular, ischemic heart disease, cerebrovascular disease.

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

“…Of these, 70 fulfilled the inclusion criteria (figure 1). 7 21–26 34–96 Of the 70 included studies, 56 estimated the short-term effects of BC/EC using a time series design or case cross-over design, while 14 studies explored the long-term effects of BC/EC using a cohort design. Thirty-seven of the 70 studies reported morbidity as the outcome variable, 25 studies reported mortality and 8 studies reported both morbidity and mortality.…”

“…In addition, the majority of the included studies on the exposure assessment were assessed as ‘probably low’ and ‘probably high’, and in some cases studies were rated as ‘high’ risk. Three studies were rated as ‘high risk’ on exposure assessment mainly because pollutants were measured with a single monitoring over a large geographical area, and not measured at least daily 53 85 92…”

“…However, in the PM 2.5 -adjusted model, no statistically significant difference was observed between EC (RR 1.039, 95% CI 0.993 to 1.083) and cardiovascular morbidity. In addition, Samoli et al illustrated that the impact of BC/EC on cardiovascular morbidity differed in the elderly and other age groups, while Atkinson et al indicated no statistically significant difference between BC/EC and cardiovascular mortality in both the PM 2.5 -adjusted model and PM 2.5 -unadjusted model 22 85. On the other hand, increased risk of long-term exposure to BC/EC and cardiovascular diseases was observed.…”

Land Use Regression Models for Particle Number Concentration and Black Carbon in Lanzhou, Northwest of China

“…An increase in the interquartile range for BC (2.7 mg/m 3 ) corresponded to increases in total, cardiovascular, and respiratory mortality of 2.3%, 3.2%, and 0.6%, respectively [12]. Some studies have shown that BC accelerates the formation of atherosclerotic plaques, suggesting long-term effects on cardiovascular health [11,13]. BC is thought to be inextricably linked to pneumoconiosis and is Sustainability 2023, 15, 12828 2 of 17 associated with increased respiratory symptoms, a slight decrease in lung function, and the accumulation of dust in the lungs [14,15].…”