Exposure to toxic parts of PM2.5 during pregnancy harmful for newborn health

A new study conducted in Europe has found that maternal exposure to particulate matter (PM) constituents such as sulphur and secondary combustion particles may adversely affect birth weight and head circumference of newborns. LBW (birth weight less than 2.5 kg) is a predictor of infant morbidity and mortality.

A mere 200 nanogramme per cubic metre-increase in sulphur in PM2.5 is found to be associated with an increased risk of low birth weight (LBW). Nickel and zinc in PM2.5 concentrations were also associated with this outcome.

The study—Elemental Constituents of Particulate Matter and Newborn’s Size in Eight European Cohorts—published in Environmental Health Perspective examined the associations of eight elemental constituents in PM2.5 and PM10. It assessed data of 34,923 births during 1994 to 2008 in Europe and estimated the annual average concentrations of eight constituents of PM2.5 and PM10 including copper, iron, potassium, nickel, sulphur, silicon, vanadium and zinc at maternal homes in different parts of Europe during pregnancy.

It was found that exposure to specific constituents of PM2.5, especially traffic-related particles, sulphur constituents, and metals was associated with decreased birth weight. Inhalation of PM can trigger maternal oxidative stress, damage cells, cause inflammation and changes in the blood system, decrease placental blood flow, disrupt transplacental oxygenation, leading to poor growth of the foetus.

The study also found that all the elemental components, with the exception of potassium, were significantly associated with smaller head circumference in newborns. Head circumference is associated with cognitive ability and child intellectual quotient.

The study was led by scientists from Centre for Research in Environmental Epidemiology, Barcelona, Spain, and jointly carried out by several research institutions.

In India, it is often stated that PM from crustal sources (such as dust) is largely responsible for poor air quality in cities like Delhi. But emerging evidence, such as the findings of this study, makes it imperative for regulators to also look into the effects of tinier toxic constituents of combustion sources in PM.

Associations of pregnancy outcomes and PM2.5 in a National Canadian Study