A weather expert associated the recent rise in air pollution in the capital Tehran to the higher ozone levels due to summer heat, dismissing social media reports that it poses a collective, grave threat to the Iranian public.
"Not all the people should be worried by the increase in the amount of ozone in Tehran's air and only the sensitive groups need to cut their [outdoor] activities," head of the air pollution committee at Iran's Ministry of Health, Abbas Shahsavani, was quoted by ISNA as saying on Wednesday.
Based on Air Quality Index, conditions are categorized into six health levels, namely Clean (0-50), Healthy (51-100), Unhealthy for Sensitive Groups (101-150), Unhealthy (151-200), Very Unhealthy (201-300) and Hazardous (301- 500).
"The elderly, children and those with respiratory problems, such as asthma, are advised to avoid strenuous activity during the day, particularly between noon and 5 p.m., over which period the sunlight is the most intense. This level of pollution is not dangerous to other groups, though they are also recommended to avoid long exposures to sunlight," Shahsavani said.
He was responding to recent reports circulating on social networking websites that raised concern about what they described as an alarming rise in the ozone content of Tehran's air.
Unlike ozone in the upper layers of atmosphere, which protects the earth from the sun's ultraviolet rays, ozone in the lower layers close to the ground is harmful to humans.
Ozone pollution is a function of air temperature, among other things, and Iranians are experiencing some of the hottest summer days. Shahsavani described ozone as the second major source of air pollution after fine particles
"This pollutant is of the most important impact after particulate matters. During the 24-day period since June 22, the first day of summer, 15 days were recorded as healthy while the other nine days were rated as unhealthy for sensitive groups. High ozone levels are to blame for those nine days," he added.
