Financial Tribune- Air quality in Tehran and other metropolises is gradually improving, thanks to the strategies of the Department of Environment, says an environment official.

According to Saeed Motessadi, DOE's deputy for human environments, Tehran saw 160 days of "unhealthy" days when air quality index exceeded 100 in the Iranian year ending March 2014, whereas there were only 63 "unhealthy" days in the current Iranian year (started March 20, 2016) up until Jan. 7.

In Isfahan, the number of highly polluted days has decreased from 257 to 52 during this period, ISNA reported.

"These figures are proof of DOE's effective measures to reduce pollution," he said.

At a press conference on Sunday, Motessadi said the authorities are pursuing the distribution of Euro 4-compliant gasoline across the country, which is currently available in eight metropolises and a number of smaller cities.

"Between 60% and 70% of the country will be supplied with Euro 4-quality gasoline by mid-2017," he said.

Another objective of the DOE is to control pollution from urban sources such as households and commercial or administrative buildings. The plan aims to reduce energy consumption in sectors contributing to air pollution.

Referring to Turkmenistan's suspension of gas supply to Iran, Motessadi said people's cooperation is needed to help meet the gas demand of power plants in Iran and prevent its replacement with mazut, a low quality and highly-polluting fuel oil.

"If people reduce the temperature of their homes by one or two degrees Celsius, supplying natural gas for power plants will not be a problem," he said.

Currently, 500 million cubic meters of natural gas are consumed in households and 160 mcm are used by power plants. Around 10% of the country's power plants use mazut.

Among the major, but rather unnoticed sources of pollution, are trucks roaming the streets at night. In Tehran alone, nearly 100,000 trucks drive around the city from 10 p.m. to 5 a.m., as a result of which the levels of PM2.5 (particulate matter smaller than 2.5 micrometers) can match or even exceed day-time levels.

Motessadi said these dilapidated vehicles not only exacerbate air pollution, but also threaten people's safety.

"We expect law enforcement forces to exert more control over these vehicles and municipalities must devise a plan to reduce emissions from these trucks," he added.