Acute Health Effects of Ozone Exposure

Study Overview
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Brief Summary
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This is a randomized controlled human exposure crossover study. Investigators aim to investigate the acute health effects of ozone exposure in healthy young adults.

Detailed Description
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The investigators will conduct a randomized controlled human exposure crossover study among 32 healthy young adults in Shanghai, China. Each subject will be exposed twice: once to clean air and once to 200 ppb ozone in a chamber for 2 hours. During the 2-hour exposure, each subject will be requested to alternate 20 minutes of rest and 10 minutes of exercise on a treadmill. The exercise workload will be adjusted to achieve the targeted ventilation of 25   27 L/min(approximately equal to 15   18L/min/m2 body surface area). Ozone will be generated by a silent electric discharge method (HTU-500, AZCO Industries Ltd., Canada) and introduced into the chamber. The temperature and relative humidity in the chamber will be maintained at 22±1℃ and 55%±5%, respectively. Health examinations will be conducted immediately prior to exposure, immediately after exposure, 2 hours after exposure and again the next morning. Health examinations include symptom questionnaire, skin tests, spirometry, and Holter monitoring. We plan to collect blood, buccal, urine, nasal secretion, saliva, exhaled breath condensate, sebum, and D-squame samples.

Official Title
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Acute Health Effects of Ozone Exposure in Healthy Young Adults: a Randomized Controlled Study

Conditions
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Pulmonary Function

Intervention / Treatment
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* Other: 200 ppb ozone group
* Other: 0 ppb ozone group


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Living in Shanghai during study period; Ability to complete the exercise to achieve the ventilation of 15 to 18 L/min/m2 body surface area; Body mass index >18.5 and ≤30.0 (30 is the lower limit for class 2 obesity for Chinese). Exclusion Criteria: Smoking and alcohol abuse; Current drug and dietary supplements intake; Subjects with allergic diseases, such as allergic rhinitis, allergic asthma, and atopy; Subjects with cardiovascular diseases, such as congenital heart disease, pulmonary heart disease, and hypertension; Subjects with respiratory diseases, such as asthma, chronic bronchitis, and chronic obstructive pulmonary disease; Subjects with chronic diseases, such as diabetes, chronic hepatitis, and kidney disease; Subjects who have a history of major surgery; Abnormal spirometry (FEV1 and FVC ≤ 75% of predicted and FEV1/FVC ≤ 0.65); Abnormal baseline 12-lead resting electrocardiogram; Abnormal blood index, such as cell counting, blood lipids, and glutamic-pyruvic transaminase (GPT).

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 30 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Exposure group<br>Subjects in exposure group will be exposed to 200 ppb ozone for 2 hours in a chamber. | Other: 200 ppb ozone group<br>* The exposure group will be exposed to 200 ppb ozone in a chamber for 2 hours while alternating 20-min rest and 10-min exercise periods. The exercise workload will be adjusted to achieve the targeted ventilation of 25   27 L/min(approximately equal to 15   18L/min/m2 body surface area). The temperature and relative humidity in the chamber will be maintained at 22±1℃ and 55%±5%, respectively.<br>|
| Sham Comparator: Control group<br>Subjects in control group will be exposed to 0 ppb ozone (clean air) for 2 hours in a chamber. | Other: 0 ppb ozone group<br>* The control group will be exposed to 0 ppb ozone in a chamber for 2 hours while alternating 20-min rest and 10-min exercise periods. The exercise workload will be adjusted to achieve the targeted ventilation of 25   27 L/min(approximately equal to 15   18L/min/m2 body surface area). The temperature and relative humidity in the chamber will be maintained at 22±1℃ and 55%±5%, respectively.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes of FEV1 | Changes of forced expiratory volume in 1 second | FEV1 will be examined immediately prior to exposure, immediately after exposure, 2 hours after exposure and again the next morning | 
| Changes of FVC | Changes of forced vital capacity | FVC will be examined immediately prior to exposure, immediately after exposure, 2 hours after exposure and again the next morning | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| HRV | Heart rate variability | Holter monitoring will be performed continuously for 24 hours. |