Numerous studies have linked air pollution and mothers smoking while pregnant to low birth weight (LBW). LBWs are strongly linked with increased risk of illness throughout life and premature death.

Two researchers in Los Angeles, renowned for its air pollution, have now focused on carbon monoxide (CO). They studied the health records of 125,573 children whose mothers had lived within 2 miles of one of Los Angeles’ 18 carbon monoxide monitoring stations, and took sex of child, level of prenatal care, ethnicity, and age of mother into account.

Of the 125,573 children, 2,813 (2.2%) had LBWs. The research showed a significantly higher risk (20% up) of LBW for foetuses exposed to higher ambient CO. The similarities between the effects of maternal smoking and exposure to CO are not surprising. CO is one of the gases generated by burning tobacco.

Another study undertaken in the ’70s showed that exposure to air pollution in LA had the same effect (an average reduction in birth weight of 314 grammes) as a mother smoking 20 cigarettes a day throughout her pregnancy.

Ed.- When inhaled, CO can penetrate tissues and is absorbed into the blood stream where it combines with the haemoglobin of blood cells 300 times faster than oxygen. This deprives the brain and heart of oxygen, causing death in extreme cases.