Pilot Study In CP Finds Disturbing Levels Of Heavy Metals That Pose Health Threat New Delhi: That the air we breathe is polluted is known to one and all. But did you know that we also breathe in heavy metals like thorium, uranium, lead and arsenic that pose a serious threat to our health? In a pilot study carried out in Connaught Place to determine the amount of particulate matter and to clean up the air, it was found that their levels were very high. The filtering station was installed outside Palika Bazaar at the Janpath-Inner Circle junction on March 6. In the 860 hours of monitoring that the machine did, a whooping 2.12 kg or 20 trillion airborne particles were trapped in its filters. Levels of PM 2.5 and PM 10 were found to be higher than the prescribed limit. When analysed by scientists, heavy metals and chemically-toxic elements were found in dust. Dr Antonietta M Gatti, who analysed the particulate matter, said while levels of the metals were not very high, their presence itself was disturbing.