Asthma has become a global public health and social problem, with the World Health Organization estimating that approximately 300 million people worldwide suffer from asthma, and the resulting social burden and health care costs have been overwhelming for many governments, families and individuals. There is considerable evidence that the prevalence of asthma is significantly higher in many countries. In some developed countries such as Europe and the United States, asthma prevalence among children and adolescents has increased significantly in the last 20 years. A survey of asthma prevalence in the Rochester, Minnesota area of the United States between 1964 and 1983 found that the prevalence of asthma increased from 183 to 284 per 1 million population. The increase was concentrated in children under 14 years of age. The second National Health and Nutrition Examination Survey (NHANES II) conducted in the United States from 1976 to 1980 found that the number of children aged 6 to 11 years who reported having “asthma” or “wheezing” symptoms was higher than that in NHANES I from 1971 to 1974. The prevalence of asthma in this age group increased from 4.8% to 7.6%. In the same year, Weitzman et al. investigated the prevalence of asthma in people under 17 years of age, which increased from 3.1% in 1981 to 4.3% in 1988. During the 11 years from 1985 to 1996, the overall prevalence of asthma in all age groups increased from 3.7% to 5.6%. Among the different age groups, the increase in asthma prevalence was more pronounced in young people. In an international study of Asthma and Allergies in childhood (ISAAC), the prevalence of symptomatic asthma among children varied widely among the population, ranging from 0% to 30%. The study used a questionnaire to investigate the prevalence of asthma symptoms in the past 12 months among children aged 13 to 14 years in 56 different countries and regions, and showed that the highest prevalence was in the United Kingdom, where the prevalence of asthma symptoms exceeded 30%, while the lowest was in Indonesia, where it was less than 3%. Studies on the epidemiology of asthma in China are limited to localized populations in a few regions and are also predominantly in children. Although the findings vary from place to place, asthma is still more prevalent in children in terms of incidence and prevalence. A nationwide epidemiological survey on childhood asthma was conducted by the National Pediatric Collaborative Group from 1988 to 1990, and the prevalence of asthma was investigated in 27 cities in China, which were divided into six areas: South Central, Southwest, East China, Northeast, Northwest and North China; 943,741 cases of children under 14 years of age were detected, with a prevalence of 9,444 cases of asthma, and the prevalence rates of men and women were 1.1% and 1.2% respectively. In 2002, the National Pediatric Collaborative Group conducted another survey on the prevalence of asthma among children in China, and the results showed that the prevalence of asthma among urban children in China ranged from 0.12% to 3.34%, with a national average of 1.54%. The results showed that the prevalence of asthma among urban children in China ranged from 0.12% to 3.34%, with a national average of 1.54%. The prevalence of childhood asthma in Chongqing is 4.36%, which is the highest in China, followed by Shanghai; the lowest prevalence is in Qinghai and Tibet. It was about 0.1%. Fewer surveys on the epidemiology of asthma in adults have been conducted. In Shandong Province, an epidemiological survey of asthma was conducted from January 1989 to June 1989 on 984,131 cases of residents in 15 localities and cities in the province. The results showed that the prevalence rate was 0.8% in pediatric patients and 0.49% in adults; among pediatric patients, there were more males than females, but among adult patients, there were more females than males. Among children with asthma, the prevalence increased with age until age 3 years, but decreased with age after age. In both children and adults, the prevalence was higher in rural residents than in urban residents. The fact that the incidence and prevalence of asthma are increasing is now well established, but the exact causes of the increased incidence and prevalence are unknown. Preliminary studies suggest that the main reasons for the increased incidence and prevalence of asthma may be related to changes in the “indoor” environment and airborne human allergens, especially house dust mites and occupational allergens, and that climate change may also be a cause of the increased incidence and prevalence of asthma.