Although a large number of people stayed home in self-quarantine as the novel coronavirus rampaged across Iran, official data show Tehran’s residents were exposed to more polluted air in March compared to the year-ago month.
Charts published by Tehran Air Quality Control Company website, Airnow.tehran.ir, show that clear blue skies were seen only for eight days in the month, meaning that the air quality index was under 50.
The index categorizes conditions dictated by 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 data show that during the month, "moderate" status was the most prevailing air condition, as the index hovered between 51 and 100 on 20 days.
Besides, sensitive groups in the capital were warned to limit their outdoor activities on three days in March, as the index ranged between 101-150.
Children, the elderly, pregnant women and those with respiratory and cardiovascular conditions fall in the above group.
Analyses illustrate that the pollutant responsible for the toxic index recorded in the month was PM2.5—atmospheric particulate matters that have a diameter of less than 2.5 micrometers.
TAQCC data illustrate that air quality condition was significantly better during the same period of last year. In March 2019, AQI had 13 "good" and 18 "moderate" days.
Wrong Analysis
Air quality in the month worsened despite the government’s repeated public alert for limiting outdoor activities to help curb the rapid spread of the novel coronavirus.
The sudden outbreak of COVID-19 in Iran since mid-February and the number of people testing positive for coronavirus rising to 53,000 compelled officials to set commutation limits on the main thoroughfares, especially between major cities and provinces.
To implement social distancing, which is considered one of the effective remedial measures against the spread of the disease, the traffic police have been strictly controlling the provinces’ incoming vehicles and banning drivers with non-local license plate numbers.
This has reportedly caused the number of inter-city travels to see a dramatic fall in Norouz (the Iranian New Year holidays between March 20 and April 3), which is usually a high travel season for the Iranian people.
However, the AQI charts still illustrate that the almost empty roads did not have a positive effect on air quality. This implies that the role of mobile sources of pollution is not determining.
Study Comes in Support
Tehran Air Quality Control Company recently conducted a study on the nature and sources of pollutants, which changes the long-presumed share of these factors in the chronic air pollution.
According to the study, the sources are mainly divided into stationary and mobile modes. Stationary sources, which include industrial units, generate 24% of the total PM2.5 in Tehran’s air quality.
PM2.5 is the most harmful due to its ability to penetrate deep into the lungs and blood streams unfiltered, causing heart attacks, respiratory diseases and premature death.
Mobile sources are blamed for the remaining 76%, including private cars, taxis, motorcycles, minibuses, buses, heavy duty vehicles and airplanes.
Based on the findings, the highest level of emission at 31% is spewed by passenger buses, even more than all the stationary sources of pollution in the city.
Heavy duty vehicles are the next most polluting source with 23.7%, followed by motorcycles with 10%, airplanes with 5% and minibuses with 4.3%.
The data illustrate that the least polluting groups are private vehicles and taxis with a respective contribution of 1.6% and 0.4%.
This is while not only have the capital’s urban managers always censured passenger vehicles for their detrimental effects on air pollution, but have also set several traffic regulations, schemes and fines to curb the use of private cars.
Weak efforts to relocate 300 industrial units in Tehran have been to no avail.
Over the past many years, city councilors and mayor have failed to address the issue effectively, blaming others for the worsening air pollution.
Smog in Tehran takes the lives of over 3,500 people every year, Iran’s Health Ministry reported.
