It is 16 years since January 19 was named "National Clean Air Day", and close to the date Tehran's air is as polluted as ever.
The capital's air has had many critical days. Even though Tehran Air Quality Control Company (AQCC) published statistics indicating abundant healthy days in Tehran, a closer look at the figures reveals 1688 unclean days that by far outnumber the only 219 clean days out of 5840 in 16 years, Eghtesad News reports.
Based on a comparative research by World Bank Databank, Tehran had the highest average of annual emissions of particulate matter with particles smaller than 2.5 micron among a 31-city collection, while Vancouver in Canada had the lowest density of the contaminant particles. The information was verified by the AQCC's CEO at the time.
The AQCC released an extensive report on Tehran pollution based on the information by international organizations that placed the metropolis among the most polluted cities in the world.
Sunday's air quality index was 93 in close proximity to "unhealthy" for sensitive groups (unhealthy index 101-150).
Emissions
Eight tons of fine particulates are generated from Tehran's daily traffic. Carburetor (a device that blends air and fuel for an internal combustion engine) motorcycles dominate the city and are a far cry from Euro 2 and Euro 3 standards. "At present, motorcycles and trucks are the main reason for Tehran's air pollution," maintains Vahid Hoseini, secretary of the National Conference on Air and Noise Pollution.
"Our surveys indicate that in the past 10 years the level of carbon monoxide has decreased gradually due to the appropriate measures taken by the Department of Environment (DoE), such as dealing with cars using carburetor and the mandatory compliance with Euro 2 standards," he said quoted by ILNA.
On the other hand the amount of fine particulates had an increasing trend in these years due to the existence of diesel vehicles, which has led to adverse air pollution in the city.
Also studies conducted show that concentration of pollutants along the highways "is significantly different from other parts of the city. This indicates that traffic is directly impacting the city's air quality."
Low Standards
During the calendar year (ends March 20) 85 days have been recorded as unhealthy and 3 days have been registered as "very unhealthy and risky", while in the previous year it was 113 days and 10 days respectively, showing an improvement in air quality, which partly can be attributed "to natural mechanisms; but we have also witnessed gradual increase in fuel quality."
He pointed out that the number of vehicles which comply with Euro 4 emission standards is still low.
At present, the state of Natural Gas Vehicles (NGVs) is also not up to the mark. Although the policy for development of vehicles powered by natural gas is prudent, however it has not been implemented correctly, since the vehicle engines should be powered by natural gas completely.
While motorcycles and trucks are the main reasons of air pollution resulting from vehicular traffic, private cars play a major role in nitrogen oxide (NOx) emissions. NOx often appears as a brownish gas. It is poisonous and a highly reactive pollutant.
The figures indicate that mortality due to heart and brain strokes is four times higher in the second half of the year which is more polluted than the first half.
