Toxic carbon monoxide emitted from engine exhausts, inhaled in low levels by city dwellers, has a narcotic effect which helps people to resist various other stresses of urban life such as noise – that's the controversial claim made by an Israeli professor investigating conditions in Tel Aviv.
According to a press release issued yesterday highlighting research by Professor Itzhak Schnell of Tel Aviv University:
Prof Schnell and his fellow researchers wanted to measure how people living in an urban environment confronted stressors in their daily lives. They asked 36 healthy individuals between the ages of 20 to 40 to spend two days in Tel Aviv, Israel's busiest city ... Researchers monitored the impact of four different environmental stressors: thermal load (heat and cold), noise pollution, carbon monoxide levels, and social load (the impact of crowds) ...
The most surprising find of the study, says Prof Schnell, was in looking at levels of CO that the participants inhaled during their time in the city. 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.
According to the prof and his colleagues, the thing which actually has the worst effect on a city dweller's health is noise: not temperature, not crowding, and certainly not carbon monoxide, which actually helps a person to cope with stress (anyway it does if breathed in the concentrations found in Tel Aviv – it's definitely poisonous at higher levels).
Schnell suggests therefore that the most urgent priority in making cities healthier to live in is not dealing with extreme temperatures or air pollution or crowding, but plainly and simply trying to make them quieter.
The research has been published in the journal Environmental Monitoring and Assessment. ®