It appears that man-made pollution, known to have detrimental effects on the environment and health, is not a modern thing. Archeologists have discovered what appears to be the first ever evidence of pollution made by man: a dental plaque of Paleolithic people from 400,000 years ago.

The well-preserved plaque provides evidence that Paleolithic people inhaled smoke while they roast meat indoors. The ancient teeth were found at Qesem Cave near Tel Aviv in Israel and these, along with everything inside the cave, were very well preserved as the cave was sealed for two centuries.

Avi Gopher, from Tel Aviv University, and colleagues have found evidence of food and potential irritants of the respiratory system that were entrapped in the dental calculus of the teeth revealing what people in the early Palaeolithic period ate.

These also revealed the quality of the air that they breathe inside Qesem Cave, which has now become a treasure trove of discoveries from the Lower Paleolithic period.

The potential respiratory irritants, which include traces of charcoal, a man-made environmental pollutant, was discovered in the ancient teeth's calculus and this could be attributed to them inhaling smoke from indoor fires that were used to roast meat everyday.

Considered as the earliest direct evidence of inhaled environmental pollution, the pollutant likely had deleterious impact of the health of the early humans. The researchers likewise said that the people who lieved in Qesem managed to find a way to control fire as they roast their meat indoors. The findings were published in Quaternary International.

"Human teeth of this age have never been studied before for dental calculus, and we had very low expectations because of the age of the plaque," Gopher said. "However, our international collaborators, using a combination of methods, found many materials entrapped within the calculus.

Besides the charcoal from indoor fires, analyses of the teeth also provided evidence of the cavemen's diet, which included seeds and nuts. The calculus also provided evidence for fibers that may have been remnants of raw materials or which were used by the early humans to clean their teeth.

Cave dwellers are known to eat animals. They hunted, butchered and roasted animals as well as used their butchered bones as tools but the discovery also provided evidence that the diet of cavemen also had a plant-based part besides the animal-based meat and fat that they eat.