Acute Health Effects of Traffic-Related Air Pollution Exposure

Acute Health Effects of Traffic-Related Air Pollution Exposure Among Healthy Young Adults: A Randomized, Crossover Trial

This study aims to assess the effects of acute exposure to traffic-related air pollution and the underlying mechanisms.

The investigators will conduct a randomized, crossover trial among 72 healthy young adults in Shanghai, China. The eligible participants will be randomly divided into 2 groups (36 volunteers per group). During the first stage, participants will be requested to take one walking task (from 13:00 to 17:30). The exposed group will walk along a busy road and be exposed to traffic-related air pollution, while the control group will walk in a traffic-free park. During the first 3 hours, all participants will rest for 30 minutes after each 15-minute walking. From 16:00, participants will stop walking and rest for 1.5 hours. Then both groups will enter a 2-week washout period. In the second stage, there will also be one walking task (from 13:00 to 17:30). The two groups will exchange their walking sites and repeat the previous trial. Physical examinations will be performed both before and after each walking task. Besides, we will ask volunteers to stay in school during the two days before walking. Health examinations include symptoms questionnaires, blood pressure tests, Holter monitoring, and spirometry. We plan to collect blood, urine, oropharyngeal swabs, and exhaled breath condensate before exposure, about one hour after exposure, and next morning.

Inclusion Criteria:

• Living in Shanghai during the study period;
• Body mass index > 18.5 and ≤ 28;
• Non-smoking, no history of alcohol or drug abuse;
• Completing the walking task we required.

Exclusion Criteria:

• Current or ever smokers;
• 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 wih 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);
• Medication use or dietary supplements intake in recent two months;