Researchers at Tel Aviv University say carbon monoxide gas could help alleviate stress of urban living, if used in small doses.
A university website said research by Professor Itzhak Schnell showed 36 healthy adults sent to pound Tel Aviv's pavements, ride its buses, and shop in its street markets suffered less than expected from traffic fumes.
"The most surprising find of the study... was in looking at the levels of CO that the participants inhaled during their time in the city," the website said.
"Not only were the levels much lower than the researchers predicted, approximately 1-15 parts per million every half hour, but the presence of the gas appeared to have a narcotic effect on the participants, counteracting the stress caused by noise and crowd density,"
"Though participants exhibited rising stress levels throughout the day, CO had a mitigating influence, and extended exposure to the chemical had no lasting effects."
Carbon monoxide is an odourless, colourless and toxic gas, which can be fatal in high concentrations. Human exposure is generally through the exhaust of motor vehicles and manufacturing plants.