Air quality monitoring stations around the capital city show residents took a heavier breath in November compared with October and the corresponding month of last year.
Charts regularly published by Tehran Air Quality Control Company’s website, Airnow.tehran.ir, indicate that “good” quality was not recorded even for a day and has become a thing of the past.
The index categorizes air conditions according to a measure of polluting matters into good (0-50), moderate (51-100), unhealthy for sensitive groups (101-150), unhealthy (151-200), very unhealthy (201-300) and hazardous (301-500).
TAQCC shows that “moderate” status was recorded in one-thirds of the month, with AQI hovering between 51 and 100 in 10 days.
Unfortunately, sensitive groups in Tehran suffer most from its toxic air. They were advised to limit their outdoor activities on 18 days, since AQI hovered between 101 and 150, marking an unhealthy status for the group.
Children, the elderly, pregnant women and those with respiratory and cardiovascular problems, all of whom fall in the sensitive group, are classed as sensitive.
Air quality condition got worse on Nov. 22 and Nov. 30, with the index respectively hitting 165 and 158, recording unhealthy status for all groups in Tehran.
High density of PM2.5 (the particulate matters smaller than 2.5 micrometers) and PM10 have been the main culprits behind the polluted days in November.
Comparisons
Month-on-month comparisons also show that Tehran’s air was duller in November compared to October.
The charts illustrate that AQI did not enter the range of good air quality even for a day, however, “moderate” status dominated the month, with the index remaining between 51 and 100 for 26 days.
Air condition was unhealthy for the sensitive group on four days, as AQI hovered between 101 and 150.
The AQI review during the year-ago month shows air quality in Tehran has deteriorated significantly.
In November 2020, moderate air quality condition was registered on 21 days, but the index remained increasingly unhealthy for the sensitive group on the remaining nine days, compelling the authorities to warn them of outdoor exposures.
AQI neither hit the emergency button, nor came down to good quality status.
Health Risks and Culprits
Poor air quality has long troubled all residents of Iranian cities.
In the capital city, the mortality figure has surpassed the shocking 5,000 a year, while road traffic accidents take the lives of around 500 in Tehran, Traffic Police Chief for Roads Brigadier General Mohammad Hossein Hamidi said.
While the causes of poor air quality in the metropolis are debated constantly, the head of TAQCC earlier blamed 100,000 dilapidated passenger cars in Tehran.
Hossein Shahidzadeh added that over 3.43 million passenger cars ply the capital’s streets every day, 100,000 of which are over 18 years old and have outlived their usefulness.
“Old cars emit 579,000 tons of toxins into the air annually, which comes down to 1,586 tons per day,” he said.
Shahidzadeh noted that of all the pollutants spewed into Tehran’s air annually, these dilapidated cars are responsible for 82% of sulfur oxide, 23% of PM2.5 and PM10, 46% of carbon monoxide and 45% of nitrogen monoxide.
He also said PM2.5 is the most harmful pollutant due to its ability to penetrate deep into the lungs and bloodstreams unfiltered, causing heart attacks, respiratory disease and premature death.
Shahidzadeh called the officials in charge to more seriously monitor the technical efficiency of cars plying Tehran’s streets. He also warned urban managers on the danger of canceling traffic rules for any reason.
However, comparisons have shown that the implementation of traffic schemes has not had much effect on curbing air pollution in the city.
With the outbreak of Covid-19 in the country, municipal bodies in Tehran lifted traffic restrictions in late March and early August to discourage people from using public transportation to curb the spread of the virus, but the measure led to clogged roads and heavy traffic.
According to Mohammad Rastegari, the head of the Department of Environment, in both rounds, the resumption of traffic schemes in the capital had close to zero effect on air pollution.
“Air quality data recorded daily by TAQCC show no decline in air pollution levels even after the resumption of traffic restrictions in the city,” he said.
Pointing to the decisive effect of environmental phenomena such as wind on air quality, the DOE official said wind can be much more effective than the most stringent traffic schemes, for it can disperse pollution and change air stability within a few hours.
This is why, Rastegari said, traffic schemes alone cannot reduce air pollution levels and can only cause minor alterations.
