Nov. 11, 2011 at 4:26 PM ET
Exhaust fumes may do more than pollute the air -- in very small amounts, they could be relieving stress in city dwellers.
An Israeli researcher has suggested that breathing in small quantities of carbon monoxide helps relax the frazzled nerves of city folk, making it easier for them to handle the hustle and bustle of urban living.
A study led by Itzhak Schnell, a professor of geography and human environment at Tel Aviv University, found that low levels of the poisonous gas can have a "narcotic effect" on city residents, says a news release. Although breathing in high levels of this colorless and odorless gas has been described as a "silent killer," extremely low levels of it may act as a "silent calmer," the news release claims.
This new study appears in the journal Environmental Monitoring and Assessment.
Schnell and his team tracked 36 young, healthy students who carried micro-sensors as they moved around Tel Aviv, Israel's busiest city. It measured participants' exposure to the typical hassles of city life. Scientists wanted to find out how four environmental stressors -- noise levels, air pollution (carbon monoxide concentrations), crowds and weather (temperature and humidity) -- affected the urbanites aged 20 to 40.
The sensors captured data from participants in indoor and outdoor locations as they walked along busy streets, rode public transportation or shopped. Measurements were taken over a two-day period in all four seasons. Students also completed questionnaires rating their levels of personal discomfort in their surroundings.
Researchers found that urbanite's biggest source of environmental stress was noise pollution from other people, mainly human voices. Participants also reported feeling the most stress in shopping malls, open markets and on main streets, likely because of the hordes of other people in these crowded locations.
According to Schnell, the study's most surprising finding was that participants inhaled much lower levels of carbon monoxide than scientists had predicted. Even though the students took in very low concentrations of the gas, Schnell says it appeared to counteract the stress of the noise and crowds.
The scientists suggest their findings show that for young, healthy people, the daily grind of city life might have fewer negative consequences on health as they had anticipated. Next, they plan to study how these same pressures of urban living affect more high-risk groups, such as babies, older people, and those with medical conditions like asthma.
Perhaps taking several deep breaths of polluted city air several times a day isn't that bad an idea, and may turn out to be a new form of urban Zen.