 London (CNN) Scientists believe they have discovered the first examples of air pollution traveling through the lungs of pregnant women and into their placentas, potentially reaching their fetuses. "We've known for a while that air pollution affects fetal development and can continue to affect babies after birth and throughout their lives," said Dr. Lisa Miyashita, at Queen Mary University of London, who also presented the research. I avoid busy roads when I walk to the station.” 
 
 A series of previous studies have shown that air pollution significantly increases the risk of premature birth and of low birth weight, leading to lifelong damage to health. Each of the women consented to having their placenta, an organ that attaches itself to the womb during pregnancy and links the mother to the fetus, examined by the research team. These cells are part of the body's immune system and tackle harmful particles such as bacteria and pollution particles, and are key in helping to protect the placenta. According to the report, the team examined 3,500 macrophage cells from the five placentas, finding that 60 of the cells contained 72 dark areas between them, which the researchers believe were carbon particles. They looked very like the sooty particles found in macrophages in the lung, which catch many – but not all – of the particles. "We do not know whether the particles we found could also move across into the fetus, but our evidence suggests that this is indeed possible," Dr. Norrice Liu, a pediatrician and clinical research fellow at Queen Mary University in London who led the research, said in a statement. “We also know that the particles do not need to get into the baby’s body to have an adverse effect, because if they have an effect on the placenta, this will have a direct impact on the foetus.” 
 
 The research is being presented Sunday at the European Respiratory Society’s (ERS) international congress in Paris. “This research suggests a possible mechanism of how babies are affected by pollution while being theoretically protected in the womb,” said Prof Mina Gaga, who is ERS president and at the Athens Chest Hospital in Greece. “We need stricter policies for cleaner air to reduce the impact of pollution on health worldwide because we are already seeing a new population of young adults with health issues.” 
 
 Unicef executive director Anthony Lake recently warned of the danger of air pollution to babies: “Not only do pollutants harm babies’ developing lungs, they can permanently damage their developing brains – and, thus, their futures.” 
 
 Separate research, also presented at the ERS congress, found that children with early onset and persistent asthma fared far less well in education than those without the condition.
– The womb protects a developing fetus, but it might not be able to fend off air pollution. Researchers have presented a small study suggesting for the first time that air pollutants can make their way from a pregnant woman's lungs to her placenta, reports the Guardian. Because the placenta allows nutrients and oxygen to flow from the woman's blood stream to her fetus, that means it could similarly allow pollutants into the womb as well, per CNN. "Our evidence suggests that this is indeed possible," says Norrice Liu, a pediatrician who led the research at Queen Mary University in London. "We also know that the particles do not need to get into the baby's body to have an adverse effect, because if they have an effect on the placenta, this will have a direct impact on the fetus." The study, presented at the European Respiratory Society International Congress in Paris, was indeed small, involving just five women. But researchers found "black sooty" particles, believed to be carbon, in the placentas of each one, says another of the researchers, Lisa Miyashita. Further analysis is in the works to confirm, but the results mirror similar ones in animals. Given previous research laying out the potential dangers that air pollution can cause to babies, the scientists say the study should factor into the advice given to pregnant women, even if it's as simple as wearing a mask or avoiding especially busy roads when out and about. The good news: All five of the women gave birth to healthy babies. (Air pollution might be the world's greatest killer.)