Urban Ozone is a silent killer

The higher the concentration of ozone (O ₃ ) in cities, the greater the risk of sudden cardiac arrest.

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Katherine Ensor, a statistician at Rice University in the United States, and colleagues analyzed data on more than 11,600 people who experienced cardiac arrest in Houston, Texas, USA from 2004 to 2011. The group The study also collected data on ozone concentrations - the main component of smoke and mist - from 44 air monitoring stations in the city, Livescience reported.

The analysis showed that if ozone concentration increased by 20 billion within three hours, the risk of cardiac arrest of humans increased by 3-4%.

Misty smoke enveloped Shijiazhuang City, Hebei Province,
China makes light bulbs in the street glow
in the morning.Ozone is the main ingredient in smoke and mist.

"In the summer months, ozone levels in Houston city often increase by about 60 to 80 billion in three hours," Ensor said.

Tim of about 1,400 people in Houston City stopped beating outside the hospital and about 1,260 of them died.

"If our findings are correct, about 45 people in Houston died due to increased ozone gas concentrations , " Ensor stressed.

Even so, Ensor said her research only found an association between ozone gas and the risk of cardiac arrest, but could not prove that increased ozone levels increase the risk of cardiac arrest.

"The risk of cardiac arrest is highest among men, African Americans and the elderly , " Ensor said.

The US Environmental Protection Agency said that ozone gas forms when air pollutants interact with each other under the influence of sunlight. So the concentration of ozone gas in the day is always higher than the night. In nature, ozone gas forms when lightning strikes occur. Some devices, such as televisions and photocopiers, also produce ozone gas. If ozone is inhaled, people will feel pain in their chest, cough and throat irritation.

According to the US Environmental Protection Agency standards, ozone levels in cities are not allowed to exceed 75 parts per billion (ie less than 75 ozone molecules per billion air molecules).