Expert answer: In hot summer, swimming is an excellent fitness exercise and leisure way, which can not only enhance physical fitness, but also relax body and mind without sweating, and is suitable for men, women and children. Swimming in the swimming pool may induce allergic rhinitis. The problem is not the swimming itself, but the water quality of the swimming pool. It is very hot in summer, and people like to soak in the swimming pool to cool off. In order to prevent diseases from spreading through the swimming pool water, the staff of the swimming pool often put disinfectant (commonly known as "bleaching powder") into the swimming pool. The main component of "bleaching powder" is sodium hypochlorite, which is a common allergen. The cleaning ingredients in the swimming pool may stimulate the nasal mucosa to some extent, and many patients are prone to allergic phenomena to sodium hypochlorite, which may lead to allergic diseases such as rhinitis, asthma and papular urticaria.