In the Twin Cities, toxic air pollutant above global permissible limit

An edited version of this article was first published in The Express Tribune on Feb 12, 2013.

Islamabad – The federal capital’s air quality might be slightly better than Rawalpindi’s, but both cities are on the wrong side of the international limit for an air pollutant.

Researchers at the Fatima Jinnah Women University (FJWU) monitored the concentration of Nitrogen dioxide (NO2) — a toxic gas that leads to the formation of other air pollutants and whose long-term exposure may decrease lung function — in the twin cities from November 2009 to March 2011.

They found the NO2 levels to be higher than the World Health Organisation (WHO) permissible limit of 21 parts per billion (ppb), averaged over a year, at all 135 sites in Rawalpindi and Islamabad where the air was sampled.

The research, conducted by Dr Sheikh Saeed Ahmad and Neelam Aziz, also measured ground-level Ozone (O3) whose concentration levels were found to be below WHO safety standard for O3.

The study was published in December 2012 in the peer-reviewed, scientific journal Environmental Monitoring and Assessment under the title “Spatial and temporal analysis of ground level Ozone and nitrogen dioxide concentration across the twin cities of Pakistan.”

The results show that concentration levels of NO2 and O3 were high in areas of intense traffic flow and congestion in both cities. These areas included dual carriageways, sub-roads, major roads, commercial areas, old residential areas and areas with educational institutions.

“The results were expected because of our traffic congestion situation,” Ahmad, who is an assistant professor at FJWU, told The Express Tribune.

Traffic congestion provides a precursor to the increase in NO2 levels because the gas is mostly produced by internal combustion engines, said Dr Muhammad Fahim Khokhar, assistant professor at the National University of Science and Technology’s Institute of Environmental Sciences and Engineering. A car engine is an example of internal combustion engine.

The maximum concentration of NO2 and O3 were observed on dual carriage ways and bus stops.

“The possible cause of this increase in concentration was the extensive increase in number of vehicles, increase in population, busy roads, fuel-inefficient vehicles, driving ways and traffic jams,” the study stated.

Khokhar said a NO2 sampling study he conducted in the twin cities in November 2012 corroborate Ahmad and Aziz’s findings.

Asif Shuja, director general of the Pakistan-Environment Protection Agency (Pak-EPA), said the agency’s own measurements in the past pointed out localized high concentrations of NO2 in dense commercial areas in Islamabad such as Aabpara.

But Shuja said the overall ambient air quality, measured by the Pak-EPA through a single air quality station in Islamabad, is below the WHO permissible limit. The ambient air quality considers an overall mix of several major air pollutants.

Rawalpindi had higher levels of NO2 and O3 than Islamabad, according to the FJWU study.

This could be due to the narrow roads, enclosing architecture of the road network and more congested areas in Rawalpindi, the study stated.

District environment officials in Rawalpindi said they are trying to curb harmful vehicular emissions by banning 2-stroke rickshaws and performing biannual smoke emission checks on motor vehicles.

But the checks are only for commercial vehicles — taxis, passenger vans, buses and trucks that transport goods

Private vehicles in the twin cities, which have increased in number over the past few years, are not considered.

“Every person is bringing out a car on the road,” Ahmad said. “If there are three adults in a house, they will often have three separate cars instead of sharing.”

The number of registered vehicles each year in Islamabad grew by 33 per cent from 2008 to 2012. Car pooling and an efficient public transport system that reduces the traffic load in the cities are ideal for NO2 reduction, Ahmad said.

Another issue is that post-18th Amendment, Pak-EPA’s domain is limited to the federal capital. At the same time, the regional or district-level environment units are not well-staffed to enforce environmental regulations on multiple fronts such as air, solid waste and water pollution.

For example, the Rawalpindi district environment office is has only three field officers and there is no ambient air quality measurement station in the city.

The effects of NO2 and O3 are not immediate; rather it is the long-term exposure to high concentration levels of these gases that could impact public health.

Ahmad and Aziz also mapped the concentration levels of the gases so further studies could be done to determine the health impact in the areas where the air is more polluted.

Ahmad hopes the FJWU study could lead to some good.

“This research provides a baseline study identifying the hot spots for poor air quality, so that policymakers can at least try and bring the precursor rate down in these hot spots,” Ahmad said.

Murree Road and Airport Road were identified as two areas most vulnerable to higher concentration levels of NO2 and O3 in the research.

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