Supertech Twin Towers Demolition: Is Dust Pollution Dangerous for Residents?
Dr Arvind Kumar answers a few questions about the possible health risks that the twin tower demolition might pose.
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On 28 August 2022, Supertech's twin towers are to be demolished as per the orders of the Supreme Court. The demolition will be achieved through a controlled explosion. Despite all precautions taken by Edifice Engineering, the company responsible for the demolition, a large dust cloud is likely to rise over the area.
This has raised concerns about the environmental impacts the explosion may have, but more so, the health risks it may cause for people living in the surrounding areas.
We asked Dr. Arvind Kumar from Medanta Hospital, a leading specialist in oncology and a pioneer in Chest and Robotic Chest Surgery in India, to answer a few questions about the possible health risks caused by this demolition.
It is being called a safe demolition. Is the process safe for the nearby residents who will be exposed to the dust clouds that arise from the demolition?
Before all the debris flies out, there will be huge amounts of dynamite, which will explode. The debris will not come down on its own. The building is going to be blasted with dynamites in what is called a measured fall method.
They will first blast the dynamite on the ground floor. So, the ground floor will collapse and the whole tower will collapse. If there are, suppose, a hundred floors, the top ninety-nine floors will collapse on the ground floor, and then the next one, and so on. In technical language, we call it intussusception.
The apex of the building will be the last to get demolished, and it will all go towards the ground floor. In the process, as each floor gets demolished, a lot of debris, concrete, etc., will fly about and there will be very high temperatures inside. Iron will also be exposed to high temperatures; so it's not just the mechanical particles, there will be lots of gaseous emissions also.
As per the usual norms that these companies follow, they surround the entire building with a concrete net, which is supposed to be made of special material, which does two things – it absorbs the shock and it prevents the debris from flying into the adjacent buildings.
What kind of damage can we expect from this demolition?
The buildings will also be surrounded, so there will be a second protective layer. Now, I don’t know if these layers will be enough to stop the chemical element, because chemicals are all molecules; they will definitely pass through any and every net. So, no matter how much protection is done, there will be some amount of gases and particles in the air.
Since you have such massive buildings being demolished, even a small amount will actually be a lot of material, which will be released into the surroundings and dissipated into the periphery depending on the air velocity. If the air is moving at high speeds, it will dissipate faster. However, if the air is moving slower, it will tend to stagnate and dissipate slower. But you should expect it to go several kilometres, from what I have heard. Something similar happened at Kochi a couple of years ago, and there was a lot of debris.
How much time will it take for the dust and pollution to dissipate?
The time period of particles being suspended in the air depends on nature; if there is heavy rainfall the next day, then the particles will come down to the ground much faster, and if we don’t have rainfall, then they will remain suspended for many days.
In fact, another thing they could have done is to have a layer of showers all around this building, which would have prevented these particles from dissipating into the surroundings. When buildings are demolished in western countries, they create a circle, a ring of showers all around, which traps the particles from getting out.
So, if there is heavy rain tomorrow evening, a lot of particles will come down and the pollution levels will decline. On the other hand, if it continues to remain dry, then it will remain suspended and will travel long distances.
Who will be impacted most because of this?
There are many kinds of pollution exposure that we are subjected to from October onwards – there will be gases, small particles, big particles, etc. So, anyone who has a pre-existing chest disease, is asthmatic, is a COPD patient, a patient who has other kinds of chest diseases, or the elderly will be prone to attacks of asthma, coughs, bronchitis, and even pneumonia. Children will also be affected because children and the elderly are the two susceptible age groups.
The damage depends on the total dose and the duration. At the building level, even if we are exposed to it for a short period, it may impact us. On the other hand, if you are exposed to a lower level, then for a clinical impact, it requires a longer duration of exposure. It also depends on your susceptibility. So, it depends on the levels and how long you are exposed. And your body’s immunity levels or disease susceptibility levels will determine whether you have a clinically susceptible disease or not.
What precautions can those people, who live near the site of demolition, take?
The safest thing for people living within a few kilometres of the area would be to move away, if possible. And the time to return would be after it has rained in the area at least once. This would ensure that all the particles come down to the ground. As for those who cannot move, they can probably use an N-95 mask with a valve. So, when we were recommending N-95 for COVID, we were insisting on valveless masks, but for air pollution, we allow N-95 with valves, which allows you to exhale the air with less resistance, and when you inhale, you inhale through the masks. It is a one-way valve, and that would be the safest thing for people to use for at least a couple of days, particularly, if they are going outdoors in those localities.
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