Black carbon, organic matter, and sulfate were significantly associated with acute aortic dissection (particularly type A) at lag 0 to 1 days, with black carbon contributing more than 50% to the joint associations of PM2.5 components with AAD risk.
Key Findings
Results
Black carbon was significantly associated with increased risk of type A acute aortic dissection at lag 0 to 1 days.
An interquartile range increase in black carbon was associated with a 42% increased risk of type A AAD (odds ratio, 1.42 [95% CI, 1.15–1.75]).
The association was observed at lag 0 to 1 days, suggesting a short-term acute exposure effect.
The association was specific to type A AAD, while the association with type B was positive but nonsignificant.
Study used a time-stratified case-crossover design in Hangzhou, China, from 2015 to 2023.
Results
Organic matter was significantly associated with increased risk of type A acute aortic dissection at lag 0 to 1 days.
An interquartile range increase in organic matter was associated with a 35% increased risk of type A AAD (odds ratio, 1.35 [95% CI, 1.10–1.64]).
As with black carbon, the association was significant for type A but not type B AAD.
Conditional logistic regression was used to explore single-component associations.
Results
Sulfate was significantly associated with increased risk of type A acute aortic dissection at lag 0 to 1 days.
An interquartile range increase in sulfate was associated with a 36% increased risk of type A AAD (odds ratio, 1.36 [95% CI, 1.09–1.69]).
Like black carbon and organic matter, the association was significant for type A but positive and nonsignificant for type B.
Conditional logistic regression was applied to explore this single-component association.
Results
Joint exposure to major PM2.5 components was significantly associated with AAD and type A AAD, with black carbon contributing more than 50% to the joint association.
Weighted quantile sum models were applied to explore joint exposure associations.
Black carbon contributed greater than 50% to the joint associations of co-exposure to major PM2.5 components with both overall AAD and type A AAD.
The joint association was significant for AAD overall and type A specifically.
Joint associations for type B AAD were not reported as significant.
Results
PM2.5 components showed positive but nonsignificant associations with type B acute aortic dissection.
Black carbon, organic matter, and sulfate all showed positive but nonsignificant associations with Stanford type B AAD at lag 0 to 1 days.
This contrasts with the significant associations observed for type A AAD.
The differential findings by subtype suggest possible pathophysiological differences in how PM2.5 components affect proximal versus distal aortic dissection.
Results
Age, smoking, alcohol consumption, and hypertension modified the associations between PM2.5 components and acute aortic dissection.
Stratified analyses based on age, sex, lifestyle factors (smoking, alcohol consumption), and existing comorbidities (hypertension) were performed.
These factors were identified as modifiers of the PM2.5 components–AAD associations, indicating differential susceptibility.
Specific effect estimates for each subgroup were not detailed in the abstract.
Methods
The study used a time-stratified case-crossover design over an 8-year period to investigate PM2.5 components and AAD in Hangzhou, China.
The study period spanned 2015 to 2023 in Hangzhou, China.
A time-stratified case-crossover design was employed, which controls for time-invariant individual confounders by using each case as their own control.
Both conditional logistic regression (for single exposures) and weighted quantile sum models (for joint exposures) were applied.
Major PM2.5 components investigated included black carbon, organic matter, and sulfate, among others.
AAD cases were classified using the Stanford classification system into type A and type B subtypes.
What This Means
This research suggests that short-term exposure to specific components of fine particulate matter (PM2.5) air pollution — particularly black carbon (from combustion sources like vehicle exhaust and burning), organic matter, and sulfate — is associated with a meaningfully increased risk of acute aortic dissection (AAD), a sudden and life-threatening tearing of the body's main artery. The study tracked AAD cases in Hangzhou, China over eight years (2015–2023) and found that exposures in the one to two days before an event were most relevant, with each of these three pollutant components linked to roughly a 35–42% higher risk of the more dangerous form of the condition (Stanford type A, which involves the ascending aorta). When looking at all PM2.5 components together, black carbon alone accounted for more than half of the combined risk.
Notably, the associations were significant for type A AAD but not for type B (which involves the descending aorta), suggesting these pollutants may preferentially trigger dissections in a specific part of the aorta, possibly due to differences in blood pressure dynamics or tissue vulnerability. People who were older, smoked, drank alcohol, or had hypertension appeared to be more susceptible to these pollution-related risks, highlighting that certain groups may face compounded dangers during high-pollution periods.
This research suggests that regulating specific PM2.5 components — especially black carbon — rather than total PM2.5 mass alone, may be important for reducing cardiovascular emergencies like aortic dissection. It also points to the potential value of targeted clinical awareness and precautionary measures for high-risk individuals (such as those with hypertension or smoking history) during episodes of elevated air pollution.
Lei M, Ji R, Wang S, Zhang C, Tu Q, Zhang Y, et al.. (2026). Associations of Fine Particulate Matter Components With Acute Aortic Dissection: A Time-Stratified Case-Crossover Study.. Journal of the American Heart Association. https://doi.org/10.1161/JAHA.126.049278