Dear Panditji,

Gobar Times is doing better with each month. This one is also very good. But my favourite is the ‘Our gurrglooing rivers’. I know that river pollution is a very grave matter. But you made it so simple. I love the lifecycle pages. The lifecycle of gold looked so gorgeous! I have a query as well. What are car air bags? How are they important?

Saira Khan
Via e-mail

Dear Saira ji,

Air bags are flexible membranes or envelopes used for cushioning, in particular for rapid inflation in case of an automobile collision. In other words, when air bag systems detect an accident, they immediately inflate to cushion the passenger with a big gas-filled pillow. They are also known as Supplementary Restraint System (SRS), Air Cushion Restraint System (ACRS), and Supplemental Inflatable Restraint (SIR).

They supplement car safety belts, and decrease the chance of the vehicle occupant hitting his or her head and upper body against some part of the interior of the vehicle. They also distribute the crash forces more evenly across the occupant’s body and thus, reduce the risk of serious injury. So instead of hitting the steering wheel or dashboard, the occupant’s body gets safely cushioned by an air bag.

A typical air bag system includes an air bag module (an inflator or gas generator and an air bag), crash sensors, a diagnostic monitoring unit, a steering wheel connecting coil, and an indicator lamp. Crash sensors prevent the air bag from inflating when the car goes over a bump, or in case of a minor collision. The inflator fits into a module consisting of a woven nylon bag and a breakaway plastic horn pad cover, placed in the steering wheel for driver’s-side applications and above the glove compartment for front passenger applications. This is how it works during collisions:

• The crash sensors located in the front of the car detect the sudden deceleration and send an electrical signal activating an initiator (also called an igniter or squib).
   
• The initiator contains a thin wire that heats up and penetrates the propellant chamber.
   
• This causes the solid chemical propellant, mainly sodium azide, sealed inside the inflator to undergo a rapid chemical reaction (commonly referred to as a pyrotechnic chain).
   
• This controlled reaction produces harmless nitrogen gas that fills the air bag. During deployment the expanding nitrogen gas undergoes a process that reduces the temperature and removes most of the combustion residue or ash.
   
• The expanding nitrogen gas inflates the nylon bag in less than 1/20 of a second, splitting open its plastic module cover and inflating in front of the occupant.
   
• As the occupant hits the bag, the nitrogen gas is vented through openings in the back of the bag. The bag is fully inflated for only 1/10 of a second and is nearly deflated by 3/10 of a second after impact. Talcum powder or cornstarch is used to line the inside of the air bag and is released from the air bag as it is opened.

Dear Panditji,

This is in response to your latest Gobar Times on mining. Can you please explain the harmful effects of mining on health? I want to know about Silicosis in particular.

Abdullah
Via e-mail

     "Dear Abdullah ji,..."     

Dear Abdullah ji,

Gone through Gobar Times of 31 August. In the course of Aditi's project on mines, she meets Arvind. The dialogue between them vividly brings out the myths and mafias of mining. Aditi's solidarity with Arvind and her appeal to leave the playground of the Arvinds across the country alone... is laudable and praiseworthy. Million thanks to Aditi!

Goutam Bhattacharya
Advisor-Environment
Hindustan Zinc Limited, Udaipur

Dear Pandit ji,

We, the Eco Club students of Sister Nivedita Sarvodaya Kanya Vidyalaya, immensely enjoy your monthly publication Gobar Times, and find it very useful. We would appreciate a lot if you could make it bi-monthly and also have its Hindi version, as our school is primarily a Hindi medium school and more students can have access to the information and perspective that you provide through Gobar Times.

Gobar Times is unique for it is the only publication that is exclusively for children and solely caters to the environmental issues, inspiring ideas and thoughts in our growing and creative minds! Once in Hindi, it will reach out to lakhs of students in all the government schools in Delhi. There can be greater participation from all these students also. We hope that you will consider our request at your earliest.

Principal, teachers and students
Sister Nivedita SKV, Defence
Colony

Dear friends,

Thank you for your valuable suggestions. Though a new version of the magazine does not seem possible immediately, we will definitely try to work towards it.

Pandit Gobar
Ganesh

Dear Abdullah ji,

Health is a critical issue for the mining sector, and is interrelated with occupational hazards. Though the average death rate in coal mines has dropped from 0.94 per 1,000 employees in 1901-10 to 0.25 in 2001-05, and for non-coal mines, the number of deaths went down by 0.76 per 1,000 employees to 0.35, the number of diseases, accidents, and fatalities is still enormous.

Mining and radiological (radiation) exposure can cause long-term disabilities. The lifespan of miners is substantially lower than that of the general population in some countries like Bolivia. Some occupational hazards associated with the mining industry:

• Hearing impairment, eye diseases, and skin diseases due to contact with allergens or irritant substances.
   
• Stress: Job stress in miners due to the conditions of work and the dangerous environment.
   
• Hazards associated with vibrations: Regular exposure to vibration causes both vascular and neural disorders such as hand-arm vibration syndrome (HAVS).
   
• Respiratory diseases: Such as silicosis, asbestosis and pneumoconiosis. Silicosis is caused by the inhalation of crystalline silica dust, a common air contaminant in hard rock mines. Pneumoconiosis is caused due to inhalation of coal dust from coalmines. The workers affected by this disease suffer from severe lung problems and are prone to lung cancer. Asbestosis happens due to inhalation of asbestos and causes chest congestions and organ malfunctions.
   
• Exposure to radioactive substances like uranium can be hazardous. It can cause cancer and mutations, and the effects may last for ages.
   
• Heavy metal poisoning (especially lead and chromium) and other forms of chemical poisoning.

Silicosis

Silicosis is caused by exposure to large amount of free silica dust, which can pass unnoticed as silica is odourless, non-irritant and does not cause any immediate noticeable effect. The disease can develop after only seven months of exposure. Silicosis can lead to complete loss of lung functions, and greatly increase the susceptibility to other lung diseases such as tuberculosis, bronchitis and lung cancer. Recently, crystalline silica has been classified as a human carcinogen (Group I) by the International Agency for Research on Cancer (IARC).

Earth’s crust contains about 12 per cent free silica mostly in the form of quartz. Thus, mining and tunnelling have high risk of silica exposure. The sandstone industry, stone quarrying, granite industry, grinding of metals, sand blasting, iron and steel foundries, silica milling, flint crushing and manufacture of abrasive soaps are some other occupations related to silica exposure.

In India, the first cases of the disease were described in the 1940s among the gold miners of Kolar. Now, there are about three million workers at high potential risk of silica exposure. And a majority of these – 56 per cent (17 lakhs) – are employed in mining and quarries.

Though the work conditions in the mining sector have improved significantly worldwide, India still has a long way to go.