Long-Term Exposure to Black Carbon Linked to Risk for Asthma, COPD

TUESDAY, Nov. 25, 2025 (HealthDay News) — Long-term exposure to black carbon (BC) is associated with an increased risk for developing asthma and chronic obstructive pulmonary disease (COPD), according to a study recently published in Environmental Research.

Jiawei Zhang, from the University of Copenhagen in Denmark, and colleagues followed 28,731 female nurses from the Danish Nurse Cohort from baseline (1993/1999) until the end of 2018 to examine the association between long-term exposure to air pollution (focusing on BC) and incident asthma and COPD.

The researchers found that 633 nurses developed asthma and 1,145 developed COPD during an average follow-up of 23 years. There was a consistent association seen for long-term exposure to BC with increased risks for both asthma and COPD (hazard ratios [95 percent confidence intervals], 1.06 [1.00 to 1.13] and 1.04 [0.98 to 1.11] per 0.34 µg/m³ increase in BC, respectively). After controlling for total fine particulate matter (PM_2.5) or no-BC PM_2.5, these associations persisted and strengthened. Among individuals with overweight or underlying comorbidity, stronger associations of air pollution were seen.

“This underscores the need for targeted air quality regulations to reduce BC emissions, which may have a greater impact on mitigating the burden of chronic respiratory diseases than focusing solely on PM_2.5,” the authors write.

Abstract/Full Text