Dear Panditji, I keep reading random stuff about the use of deodorants and their ill effects. Can you please make me understand how a deo works and if it is harmful at all or not? Ashish (via email) Dear Ashish Deodorants (including anti-perspirants) are so important, you just can't go out without them in summers. When you are feeling hot or nervous your sweat glands kick in and release sweat that cools down your body immediately. The bacteria in it multiply in hot and humid conditions such as your armpits (they have between 25,000 and 50,000 sweat glands) and create an odour. It is this odour that deodorants (deo) target. Anti-perspirants contain aluminium salts which dissolve in sweat and essentially block the sweat glands with a thin coating of gel. The salts also make the glands contract, further reducing the possibility of sweating. Alcohol and antimicrobials in deos in turn kill bacteria and release a fragrance that masks bad smells. The release of sweat is minimised in regions where the deo is applied. Scientists have not reached a consensus about the health affects of deos. Rumours like deos cause breast cancer have generally been rejected. Some people may develop skin allergies to aluminium which can also lead to DNA damage. According to some studies, excessive use of aluminium can lead to lung problems, neurological damage and a higher risk of Alzheimer's. People with renal dysfunction are advised to stay away from deos. They often come as aerosol (tiny particles of solid and liquid suspended in air) sprays. If inhaled they can cause illnesses like asthma and diarrhoea. Exposure over a long period of time can also lead to problems like headaches, nausea, shortness of breath, eye, throat and lung irritation, skin rashes, burns and even liver damage. Dear Panditji, I love swimming but I am always concerned about the cleanliness of swimming pools in clubs etc. I asked my coach and he said that the water is treated with chlorine to make it clean. Can you please help me understand how that is done? Anu (via email) Dear Anu Please continue swimming! It is a great exercise. But I agree that you need to know how clean your pool is, especially when a lot of other children share it with you. It is actually a simple chemical reaction. After pouring the chlorine, preferably in the middle of the pool, the water is stirred for about 30 seconds. The cleaners then wait for 30 minutes for the water to settle. During this time, the chlorine breaks down to hypochlorous acid (HOCl) and hypochlorite ion (Ocl-) among other chemicals. Both attack microorganisms and bacteria, destroying the enzymes in their cells. Bacteria is then left oxidised. To neutralise the affect of chlorine a chemical like ammonia is used. Sunlight also helps in this process. Pools which are used for long hours by several people need chlorinated cleaning three to four times a week. About once a week, the pool should be 'shocked', that is, superchlorinated (four to five times stronger than normal chlorine) to burn any bacteria and algae. All the walls and floor should also be cleaned once a week with a brush. Dear Panditji, I read about a solar mobile phone by Samsung. Is it true? Can mobile phones really get charged with solar energy? Kabir (via email) Dear Kabir Yes! You got it right! Samsung came out with India's first solar-charged mobile phone the 'Solar Guru' in 2009 and the 'Blue Earth' in the following year. Gone are the days when your cell phone almost died when you left it in sweltering heat by mistake. This one will crave for the sun light that is provided to us in abundance. Solar Guru's mini solar panels on the back of the phone take one hour to provide five to 10 minutes of talk time. It promised to be a boon to rural areas and urban slums where power supply is non-existent or unstable. It is also priced (Rs 2,799) keeping this market in mind. Not only does it use a clean form of energy, it is also crafted from recycled plastic bottles and is toxin-free. The solar panel on the back of the phone can be recharged by exposure to UV light. Not to be left far behind, Vodafone has also come up with a solar-powered mobile handset for rural India. Priced at just Rs 1,500, the phone charges under normal daylight too. All the phones come with an AC adapter as well, which can complement the solar panels in powering the phone. Dear Panditji, Is it true that we should use the AC to cool our rooms up to 25 degrees and not lesser? If so, why? Kavita (via email) Dear Kavita Thanks for asking this question. A lot of our readers need to learn this lesson. Yes, we should use ACs to cool our room at about 25°C because it helps maintain a balance between comfort and economy. Sure it is tempting to lower the AC temperature during the summer heat, but doing so unnecessarily raises costs without necessarily raising comfort. Your body needs to comfortably adjust to external temperatures without any changes to your body temperature. Lowering the temperature of an AC may cause problems in its functioning. For example, when ACs are set below 21°C, they starts creating ice. Mould will start growing in your room and paint will start peeling off your walls in low temperatures. If you don't find 23°C cool enough, here are some things you can do: Shut doors and windows to prevent cool air from escaping Switch on the fan if you haven't already Clean your AC's filter at least once in two weeks – at most, a month.