Peak expiratory flow varies among adolescents with exposure to particulate matter

Key takeaways:

• Sources of PM_2.5 in the area included vehicle emissions, industrial exhaust and landfills.
• Peak expiratory flow varied with changing PM_2.5 conditions.
• Patient education about air quality remains a challenge.

WASHINGTON — Ambient particulate matter pollution at the 2.5 µm scale influenced peak expiratory flow among adolescents in Mobile, Alabama, according to data presented at the American Thoracic Society International Conference.

“We recruited students from the local high school, and we wanted to assess how air pollution affected their airflow variability,” Marcy Cage, MPH, third-year PhD student in the department of physiology and cell biology at the University of South Alabama Whiddon College of Medicine, told Healio.

The researchers noted that particulate matter at 2.5 µm (PM_2.5) increases the incidence, prevalence and frequency of exacerbations in asthma and other pulmonary diseases. Sources of PM_2.5 in Mobile vary, Cage said.

“Mobile, I guess you would say, is suburban,” Cage said. “But Mobile does have a lot of industry. Of course, we have a lot of farming.”

Since it is near the coast, storms impact air quality and health among children and adolescents as well, Cage continued.

“Mostly, our PM_2.5 comes from emissions, industrial exhaust and landfills that we have in the area,” Cage said.

The study involved 20 boys and 24 girls aged 14 to 18 years. Pulmonary function tests found a mean forced vital capacity (FVC) of 4.37 L ± 1 and a ratio of FEV₁ to FVC of 85% ± 7.

These students completed a questionnaire as well, which found 16% with a history of asthma and 2% with a history of other respiratory problems. Also, 75% had lived their entire life in Mobile, and 20% had lived there between 5 and 10 years.

The questionnaire additionally found that 25% of the students used electricity and 75% of them used gas both for cooking and for heating at home. Plus, 28% said trucks never pass through the street where they live, 44% said trucks are seldom seen on their street and 33% said truck traffic is frequent through the day.

The researchers then gave each student a peak flowmeter, which the students used in the morning and in the afternoon each day for 5 weeks. Data were recorded electronically. After that, the researchers collected the flowmeters and conducted a second pulmonary function test.

“We found that peak expiratory flow actually differed with changing concentrations of PM_2.5 in the area,” Cage said.

On average, the students had a pre-FEV₁/FVC ratio of 78.79% and a post-FEV₁/FVC ratio of 85.7%. Also, FVC measurements increased with height (median = 68 ± 3 inches) and differed between the sexes.

Based on these findings, Cage said that doctors should always consider the PM_2.5 levels that their patients may be exposed to and ask questions about where they live, whether they walk to school, and other potential influences on their respiratory health.

For example, she said, there is a school in Mobile that is located next to a landfill.

“What are these things that trigger asthma?” Cage asked. “It helps patients make better decisions about control.”

In fact, Cage called patient education a challenge as many students, their families and their teachers are not aware of the impact that air quality can have on their health, despite the availability of information through online resources.

“I was talking to a high school teacher, and she said, ‘Yeah, we never knew that we could check air quality,’” Cage said, adding that patients could be taught to access this information via their smart phones. “So, there is stuff that’s there.”

Next, Cage and her colleagues will continue recruiting more students.

“I’m going to try for a more diverse population,” Cage said, noting that 86% of the sample was white. “That’s not reflective of Mobile, Alabama, so I need to have a population that’s more reflective so that we can know where this impact really falls.”

For more information:

Marcy Cage can be reached at mac2022@jagmail.southalabama.edu.