The risk of giving birth to babies with defects or disorders could increase 30 percent if the ozone concentration pregnant women are exposed to during the first four weeks of pregnancy rises by one part per billion (ppb), the Sky Post reported Monday.
The new finding was published by the China Medical University of Taiwan in a recent issue of Environmental Research Journal, having drawn comparisons between 1,687 infants with birth defects born between 2001 and 2007 and 16,800 healthy newborns, after excluding factors such as smoking and drinking habits of the mothers.
The study has led some specialists to link the increase in the number of cases of birth defects in Hong Kong to environmental factors. The ozone level in Hong Kong has reached new highs this year, especially in Tai Po and Sha Tin.
According to the Hospital Authority, there were over 10,000 cases related to birth defects in 2012. Cheung Tak-hong, chairman of the Hospital Authority committee said, the increase could be due to environmental factors, the increase in the number of mothers getting pregnant at an older age, and insufficient pre-natal check-ups among expectant mothers.
Ozone concentration in Hong Kong during the first six months this year averaged 43 micrograms per cubic meter of air (roughly 0.043 ppb), which is 80 percent higher than the standard set by the World Health Organization. In Tap Mun, Sha Tin and Tai Po, the figures were even higher.
Kwong Sum-yin, chief of the Clean Air Network, said ozone is formed by the chemical reactions of volatile organic compounds from motor vehicles under sunlight. Combustion-generated nitrogen oxide from motor cars has led to an increase in ozone-forming pollutants, Kwong added.
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