NCT05680831

Pulmonary and Inflammatory Responses Following Exposure to a Low Concentration of Ozone or Clean Air

Pulmonary and Inflammatory Responses Following Exposure to a Low Concentration of Ozone or Clean Air for 6.6 Hours With Moderate Exercise in Healthy Young Adults

• Status: Unknown
• Phase: Phase 1
• Study type: Interventional
• Enrollment: 60 (estimated)
• Sponsor: Martin W. Case · Federal
• Sex: All
• Age: 18 Years – 35 Years
• Healthy volunteers: Accepted

Summary

Purpose: The primary purpose of this study is to measure pulmonary function, symptoms, and pulmonary inflammatory responses in healthy young adults during and immediately after exposure to a low concentration of ozone (0.070 ppm) or clean air for 6.6 hours while undergoing moderate intermittent exercise. This concentration is the current EPA NAAQS standard for ozone.

Detailed description

Potential health effects of ozone have been extensively studied over decades at various levels of exposure concentration and for varying time periods in young healthy adult subjects. Effects of ozone have been well documented particularly for decrements of lung function and an influx of neutrophils and other markers of pulmonary inflammation. The majority of those studies were done at ozone concentrations between 0.12 and 0.40 ppm, considerably higher than the current EPA NAAQS ozone standard of 0.070 ppm, and at exposure durations of two hours, even though the current standard is an 8-hour standard. However, a small number of studies have assessed changes in lung function following exposure to low levels of ozone for several hours. These latter studies have shown that exposure to ozone for 6.6 hours at concentrations between 0.06 and 0.08 ppm causes mild reversible decrements in lung function (1.7-10%) as measured by forced vital capacity (FVC) and forced expired volume at 1 s (FEV1) immediately after exposure in healthy young adults. In addition, in one study an increase in ozone-induced neutrophils was seen in induced sputum following exposure to 0.06 ppm ozone (8) and in bronchoalveolar lavage fluid) following exposure to 0.08 ppm ozone (9). The EPA is considering whether the current ozone NAAQS standard at 0.070 is protective and has asked EPA researchers to conduct a study similar to those done at 0.06 and 0.08 ppm.

Conditions

• Lung Injury, Acute
• Symptoms and Signs
• Neutrophilia Acute

Interventions

Type	Name	Description
BIOLOGICAL	0.070 ppm ozone concentration	The concentration of ozone a subject will randomly receive on a visit for 6.6 hours in a controlled atmospheric chamber while performing moderate intermittent exercise.
BIOLOGICAL	Clean air (0.0 ppm ozone)	Same subject will randomly receive clean air on another visit separated by at least one week for 6.6 hours in the same controlled atmospheric chamber while performing moderate intermittent exercise.

Timeline

• Start date: 2022-10-13
• Primary completion: 2024-02-01
• Completion: 2025-02-01
• First posted: 2023-01-11
• Last updated: 2023-01-11

Locations

1 site across 1 country: United States

Regulatory

• FDA-regulated drug study