Peshawar has 450 brick kilns and hydrogen fluoride is also released by factories making aluminium, ceramics and phosphate fertilizers.
Scientists from the Netherlands, Pakistan and the UK report, despite the potential of high fluoride emissions to damage to crops, “the impact of these brick kilns on agriculture production and farmers’ livelihood in Asia is poorly understood.
The scientists looked out for visible signs of injury to leaves, such as burnt-looking tips, besides the amount of fluorides and sulphur in the leaves of apricot, plum and mango trees. They also interviewed local farmers about their observations of tree injury in orchards.
More leaf injury and higher hydrogen fluoride levels were observed near brick kilns, which indicated emissions from brick kilns were the main cause of damage to trees, the report said. Interviews with farmers also suggested significant impact from crop damage on livelihoods, the study said.
“Once Peshawar’s surroundings were ideal for farming but, now in the presence of 450 brick kilns, the story is entirely different,” said Muhammad Nauman Ahmad, Assistant Professor in the Agriculture University of Peshawar.
Numan said hydrogen fluoride could destroy 40-60 per cent of the tree yields. The polluting gases enter leaves through tiny openings called stomata and damage cells, giving fruits a “squeezed” appearance, he said.
Hamidullah Shah, professor and head of the agriculture chemistry department at the Peshawar Agriculture University, who was part of the research team, said damage due to hydrogen fluoride was marginal in winters, but worsened as the weather warmed.
Pervaiz Amir, an agriculture economist at the Asianic Agro-Development Institute, Lahore, explained brick kilns were contributing to the brown clouds and smog that were increasing across Pakistan due to rapid industrialisation.
According to Amir, wheat yields were already declining due to changes in the environment and “could further decrease by 20-25 per cent in the 2012, reducing per capita income and national wealth”.
Besides pollution to plant-life, emissions of air pollutants like carbon monoxide, sulphur dioxide, nitrogen oxides and particulate matter for burning coal in kilns lead to respiratory ailments like bronchitis and asthma. These chemicals affect the immune system of the human body.
Brick production is concentrated in four Asian countries – China, India, Pakistan and Bangladesh, which account for 75% of the global production.
In India alone, there are over 100,000 brick kilns, largely in the unorganized sector, which are responsible for about 30 per cent of air pollution in the country. A recent study noted, the country’s building stock is expected to multiply five times by 2030, with solid fired clay bricks the most widely used – and highly polluting – building materials.
The study by Clean Air Task Force alongwith New Delhi-based Greentech Knowledge Solutions says, “Despite its significance in the construction sector, importance in livelihoods of the poor, being a large coal user and causing environmental health and impacts, the brick making sector has seen very few development interventions/ programmes aimed at improving the industry.” (With inputs from http://www.sciencedev.net)