Details are regularly published by TAQCC on its website, airnow.tehran.ir. In January the sprawling capital experienced less polluted days in January compared to a year earlier.
Tehran saw two days with blue skies, with the air quality index showing 'good' conditions. Likewise, the city had 17 days of 'moderate' air quality.
The index compartmentalizes 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), according to Financial Tribune.
TAQCC charts show that in January 2018 sensitive groups in Tehran breathed 12 days in "unhealthy" conditions, with the index between 101 and 150.
Children, the elderly, pregnant women and those with respiratory and cardiovascular conditions, all of whom fall in the sensitive group, were advised to avoid prolonged outdoor exertion.
Comparisons
This is while over the past several years, air pollution in the metropolis decreased, at least during the period under the study, according to TAQCC data.
January 2018 started with a lot of toxic emission in the air on the first day as the AQI stood above 150, marking ‘unhealthy’ air condition for all groups.
During the month, sensitive residents encountered unhealthy air conditions as pollution dominated TAQCC charts, pushing up the index between 100 and 150 for 18 days.
The remaining 12 days of the month had 'moderate' air quality with not a single day of 'good' AQI.
Things become worse if the air quality chart of January 2017 is reviewed. At the time, the overcrowded metropolis again did not see a single day of good air and residents breathed in ‘unhealthy’ air conditions for two days, with the index hovering above 150.
The rest of the month passed with air pollution forcing sensitive groups indoors for 17 days with the AQI between 101 and 150. In the remaining 12 days, air quality was in the ‘moderate’ range.
Methodology
AQI standards have been the function of the High Council for Environmental Protection since 2012. Reportedly, the procedure is a translation of the 2012 version of standards set by the United States Environmental Protection Agency that is no longer in use today.
Pollutants measured to determine air quality include carbon monoxide, nitrogen dioxide, sulfur dioxide, ground-level ozone and particulate matter (PM2.5 and PM10). AQI figures are calculated based on the concentration of pollutants.
Poor air quality has long been a danger for most metropolises in Iran causing over 12,000 pollution-related deaths in the fiscal that ended in March 2017, the Ministry of Health reported.
Seemingly things are getting better regarding, at least in Tehran. This could either be thanks to nature's help or assorted healing measures taken by municipal bodies.
In November 2018, Tehran Municipality implemented the Air Pollution Reduction (APR) in a new effort to improve air quality.
APR bars dilapidated vehicles from the roads and violators are fined. All four and two-wheelers in the metropolis must go for the inspections and acquire conformity cards showing that the vehicle is roadworthy.
Another scheme introduced in 2005 is the odd-even rule which aims to curb air pollution and traffic congestion in Tehran.
As per the odd-even rule, cars are only allowed to enter the designated ‘restricted zone’ on alternate days depending on the odd and even number of the license plate. The restricted zone is an 88.5 square kilometer area in central Tehran limited by Imam Ali Expressway in the east, Navvab Expressway and Chamran Highway in the west, Besat Expressway in the south and Hemmat Expressway in the north. Saturday is earmarked for cars with the last even digit and Friday, being the weekend, is not included in the scheme.