Diesel exhaust exposure is harmful for former smokers with COPD as compared to former smokers without COPD or healthy never smokers, reveals a recent study. The research by a team led by Dr Min Hyung Ryu in the Channing Division of Network Medicine at Brigham and Women’s Hospital, and Harvard Medical School, conducted a double-blind, controlled human crossover exposure study that enrolled 30 participants, and found that former smokers with COPD had increased serum amyloid A and matrix metalloproteinase-10 in bronchoalveolar lavage when exposed to diesel exhaust.