Shanghai children were found to have the highest incidence of childhood asthma among 10 major cities in China - a level almost 56 percent higher than the average for those cities, according to a new study.
The Chinese Society for Environmental Sciences based the study in part on questioning the parents of thousands of children between three and six years old in Beijing, Shanghai, Xi'an, Wuhan, Harbin, Taiyuan, Chongqing, Changsha, Nanjing and Urumqi. They combined that information with analysis of the children's residence, habits and outdoor environment, officials said on Monday.
The study, conducted from 2010 to 2011, is part of the International Study of Asthma and Allergies in Childhood.
The average incidence of children's asthma in the 10 cities was 6.8 percent, while it was 10.6 percent in Shanghai. The 10-city average was much higher than the 0.91 percent found in 1990 and 1.5 percent in 2000, officials said.
While several of those cities regularly register worse overall air pollution than Shanghai, officials said outdoors pollution was not the only factor contributing to childhood asthma and other allergy-related illnesses.
Children living in areas with high humidity, where it is hot in summer and cold in winter and there may be insufficient heating equipment, have a higher incidence.
Researchers said the major reasons for indoor air pollution include the frequent use of new and synthetic materials in renovation; poor ventilation, especially in the kitchen and bathroom; improper installation and use of air-conditioning systems, and outdoor pollution.
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