Chinanews, Beijing, May 30 – Most people are aware that outdoor air pollution can damage their health but may not know that indoor air pollution can also have significant effects, warns Song Guangsheng, director of China Indoor Environment Monitoring Committee.According to China epidemiologic statistics，the natural incidence of leukemia nationwide is 3 out of 100,000 people, and 40,000 people are diagnosed with leukemia every year, 50% of which are children, mainly aged from 2 to 7 years old.Officials with China Indoor Environment Monitoring Committee suggest that children living in areas of high formaldehyde air are at increased risk of developing leukemia, because there is a possible association between formaldehyde pollutants and the incidence of children leukemia.Data from Beijing Children's Hospital indicate that over 90 % of urban children diagnosed with leukemia have their houses decorated no more than half a year ago.Similar data results have been shown by Shenzhen Children's Hospital.