With the increasing degree of industrialization and the growing number of allergens accessible to humans, allergies are on an annual rise worldwide, reaching almost epidemic proportions. Many people who were not allergic in the past have now become part of this group, making allergic diseases a common condition. Studies have found that the incidence of allergic diseases is higher in developed countries and regions compared to developing countries, and higher in urban areas than in rural areas. Children in rural areas are less likely to suffer from allergic diseases. In developing countries, the increase in allergic diseases is associated with urbanized lifestyles. Xiao Wang, a migrant worker, started working for a pet company in the city less than a year ago after moving from his rural hometown. With the arrival of spring, the formerly robust Xiao Wang inexplicably began to suffer from runny nose and nasal congestion; it turned out he had developed an allergy. The stimulation of certain chemical substances, dust, animal proteins, enzymes, etc., in the work environment triggered allergic diseases. Studies also show that in cities, children of high-income parents or professional elites are more likely to...