Even short-term exposure to diesel exhaust may be particularly damaging to former smokers with chronic obstructive pulmonary disease (COPD), according to new research.

Performing bronchoalveolar lavage (BAL) 24 hours after exposure to diesel exhaust, researchers conducted cell counts on blood and airway samples and took other measurements to assess inflammatory proteins.

“Our data suggest that exposure to short-term moderate concentrations of diesel exhaust may be more harmful to former smokers with COPD compared with those without COPD, given the differential response in relevant markers as detailed in our results,” the researchers write.

Dr. Min Hyung Ryu, a postdoctoral research fellow in the Channing Division of Network Medicine at Brigham and Woman’s Hospital and Harvard Medical School, and colleagues reported their findings in the American Journal of Respiratory and Critical Care Medicine.

With cases of COPD on the rise worldwide, the researchers wanted to study whether COPD can be exacerbated by air pollution exposure. COPD refers to a group of diseases that cause airflow blockage and breathing-related problems.

The study included 30 participants. Ten were former smokers with mild to moderate COPD, nine were former smokers and healthy and 11 were healthy and had never smoked.

The participants were exposed to diesel exhaust such as might be present on congested, urban highways.

Those who were former smokers with COPD showed increased inflammatory proteins not seen in non-smokers or former smokers without COPD. The researchers acknowledge that the small sample size is a limitation of their study.

COPD is the third-leading cause of death worldwide, with 80 percent of those deaths occurring in low- and middle-income countries, according to the World Health Organization (WHO).

COPD affects more than 15 million Americans, according to the Centers for Disease Control and Prevention (CDC). More than 150,000 Americans die of COPD each year, or one death every four minutes, the CDC says.

As the number of baby boomers grows and COPD cases increase across the nation, respiratory therapists (RTs) are taking on new roles as COPD navigators, helping patients who get caught up in a cycle of trips to the hospital and back home. The RT’s job is to provide more preventative care and interventions to help patients better manage their own care at home and avoid repeat hospital visits.

The result of long-term exposure to harmful gases and particles, in combination with individual factors, COPD is considered common, preventable and treatable, the WHO writes.

Documented risk factors include environmental exposure to tobacco smoke, indoor air pollution and occupational dusts, fumes and chemicals.

“In the global fight against pollution, human exposure studies are critical in providing key mechanistic insights to support legislation for public health protection and to shed light on future prevention and therapeutic approaches to protect those who are more susceptible from the harmful effects of air pollution,” the researchers write.