Severe air pollution may cause birth defects, deaths: Study

Harmful particulate matter in the atmosphere may lead to birth defects and even fatalities during pregnancy, according to a study conducted in mice. Researchers at Texas A&M University in the US examined the adverse health effects of exposure to fine particulate matter consisting of ammonium sulphate commonly found in many locations around the world. During winter months in India and China, where severe haze events frequently occur, fine particulate matter levels are especially high at several hundred microgrammes per cubic metre, they said.

According to the World Health Organization (WHO), nine out of 10 people worldwide breathe air containing high level of pollutants.

One out of every nine global deaths can be attributed to exposure to air pollution, totalling over seven million premature deaths a year, researchers said.

“People typically believe that ammonium sulphate may not be terribly toxic, but our results show large impacts on female pregnant rats,” said Renyi Zhang, a professor at Texas A&M University.

“It is unclear yet what is causing these profound effects, but we speculate that the size of nanoparticles or even the acidity may be the culprit,” Zhang said.

Sulphate is mainly produced from coal burning, which is a major energy source for much of the world in both developed and developing countries.

Ammonium is derived from ammonia, which is produced from agricultural, automobile, and animal emissions, “so this certainly represents a major problem worldwide,” Zhang said.

“However, our results show that prenatal exposure to air pollution may not dispose offspring to obesity in adulthood,” said Guoyao Wu, Texas A&M University Distinguished Professor and one of the lead authors of the study.

“Nutrition and lifestyle are likely major factors contributing to the current obesity epidemic worldwide,” Wu said.

Numerous previous studies have shown that air pollution is a serious public health threat throughout the world, with millions of people breathing air that is far less than standards set by the WHO.

Previous studies have shown such pollution to impair metabolic and immune systems in animal offspring.

However, the study shows definitive proof of decreased foetal survival rates, and also shortened gestation rates that can result in smaller body weight, in addition to damage to brains, hearts and other organs in the adult rat models.

The findings present obvious concerns and challenges on a multi-scale level, the researchers said.

“While epidemiological studies have been widely adopted to assess the health effects of air pollution, these tend to yield little insight into adverse outcomes and long-term effects,” Zhang said.

“Furthermore, there is an absence of clinical recommendations for prevention and treatment of air pollution-related health issues.

“Our study has demonstrated that well-controlled exposure experiments using animal models offer major advantages for future air pollution control and are promising in the development of therapeutic intervention and treatment procedures,” he said.