This study aims to evaluate whether dietary supplementation with fish oil can protect against the cardiopulmonary effects induced by ozone exposure.

The investigators will conduct a randomized controlled trial among 64 healthy young adults in Shanghai, China. The eligible participants will be randomly assigned in a 2*2 factorial design to 1 of 4 groups: 1) fish oil and ozone exposure, 2) fish oil and shame exposure, 3) soy oil and ozone exposure, or 4) soy oil and shame exposure. The participants who take fish oil would receive 2.2 g/day (two 1.1-g capsules daily) in divided doses, and other participants will take the same amount of soy oil capsules. Two hour ozone exposure (200 ppb ozone) or shame exposure (0 ppb ozone) will be conducted in a chamber after four weeks of supplementation. Ozone is 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 are maintained at 22±1℃ and 50%±5%, respectively. During the 2-hour exposure, each subject alternate 15 minutes of exercise on a treadmill and 15 minutes of rest. The exercise workload would be adjusted to achieve the targeted ventilation of 20±1 L/min/m2 body surface area. Health examinations will be conducted immediately prior to exposure, immediately after exposure, 2 hours after exposure and again the next morning.

Inclusion Criteria:

• Living in Shanghai during study period;
• Ability to complete the training exercise to induce an inspired ventilation rate of 20±1 L/min/m2 body surface area;
• Body mass index >18.5 and ≤30 (30 is the lower limit for class 2 obesity for Chinese);
• Taking the fish oil or placebo on time.

Exclusion Criteria:

• Being allergic to seafood;
• Smoking and alcohol abuse;
• Current drug and dietary supplements intake;
• Subjects with allergic disease, such as allergic rhinitis, allergic asthma, and atopy;
• Subjects with cardiovascular disease, such as congenital heart disease, pulmonary heart disease, and hypertension;
• Subjects with respiratory disease, such as asthma, chronic bronchitis, and chronic obstructive pulmonary disease;
• Subjects with chronic disease, such as diabetes, chronic hepatitis, and kidney disease;
• Subjects with 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).