For some people, as these postings to my forum illustrate, static electricity is more than just an occasional mild annoyance:

"My husband has some electric sparks from his body. Whenever he touches things it sparks and with fire clicks, like when he is opening the door or sometimes even when shaking people's hands. What could be the problem? Sometimes when he is touching me too, I feel the shock. It is scary."

"I live in a commune; I have a friend here who always gets a shock when touching something metal. It has got so bad that he calls me from my room when he wants to open a door with metal handles. What can be the problem or the solution?"

"This may sound strange, but I have very high levels of static electricity in my body. In winter I seem to 'shock' everyone and myself constantly, and things stick to me (like paper etc.). Any idea what this could be from?"

What is static electricity?
Static electricity occurs when electrical charges (called "electrostatic charges") build up on the surface of an object, usually when different materials are rubbed against each other. Electrons, the negatively-charged particles in matter, are pulled from the surface of one material onto the surface of the other: the material that loses electrons acquires a positive electrostatic charge and the material that gains extra electrons acquires a negative electrostatic charge.

Certain materials, including silk, wool and most synthetic materials (like nylon), tend to build up electrostatic charge much more easily than others.

For example, if you walk over a nylon carpet with plastic shoe soles, electrons move from the carpet onto your shoes. Then, if you touch a metal object (like a door handle) or someone’s hand, the extra electrons move from you onto the metal object or other person, and, if the discharge of electrons is large enough, you can feel it as a mini-shock.

Sometimes, electrons jump through the air gap between you and the other object, and this can heat up the air and cause a spark. Lightning is an electrostatic "spark" on a much grander scale: electricity discharges from a storm cloud across the air gap to another cloud or the earth, resulting in a lightning bolt.

Another classic example of static electricity is when you pull a sweater over your head in dry air – and your hair literally stands on end. Your hair loses electrons to the sweater and becomes positively charged, which means each strand gets positively charged. Objects with the same charge (positive-positive or negative-negative) repel each other, so each hair tries to get as far away from its neighbours as possible, resulting in the familiar fly-away hair effect.

If your hair or clothes have a sufficiently high electrostatic charge, they may attract objects of opposite charge (positive attracts negative); if these are small, light objects, such as scaps of paper or a fold of clothing, they may stick to you.

Is static electricity harmful?
Lightning aside, the kind of static electricity that can build up on our bodies and everyday objects, and the mini-shocks that may result, usually only cause mild discomfort, and have not been shown to have a detrimental effect on human health. Some people do appear to be particularly sensitive to static shocks, however, and in such cases this can contribute to stress levels.

In some circumstances, static electricity presents a safety risk. Flammable liquid or vapour can be ignited by an electrostatic spark, and this needs to be protected against in certain industries.

There is a low, but real, risk of this happening at petrol stations, where there are flammable petrol fumes. It is therefore advisable that you stay in your car while refuelling to avoid creating an electro-static spark. (You can build up a charge just by sliding across the car seat. Then, if you get out of the car and reach for or touch a metal object – like the nozzle of the petrol hose – you could create a spark.)

Why are some people more ‘sparky’ than others?
Some people produce more electrostatic charge than others, for various reasons including body size and the materials their clothing and shoes are made of. Clothes made from wool, silk or synthetics can all cause electrostatic charge to build up. Some people simply feel electrostatic shocks more than others.

Ways to reduce electrostatic build-up and shocks
Wear more cotton and linen, and try shoes with different soles (i.e try leather if your rubber soles seem to make you sparky). Around the house, going barefoot should help. The floor surfaces in your home may be contributing too: you may want to consider replacing your wool or nylon carpet, or having it treated with an anti-static product.

Static electricity occurs more often in dry air (water molecules impede the build-up of electrical charges); in winter, indoor heating tends to dry out the air. Installing a humidifier in your home can help with this. Moisturising your skin (especially the parts that seem to be building up charge) might also help.

Try grounding yourself by touching a neutral surface, like a wall or wooden door, to help dissipate any charge before you touch a metal object or another person.

Another method is to hold a metal object and then touch it to a metal surface before you do. For example, many people get shocked when they touch the metal car door just after getting out of the car. If you hold a key while you’re getting out, and touch this to the car door first, the electricity will discharge from the key instead of from your hand. The same trick can be used to avoid getting shocks from shopping trolleys.

- (Olivia Rose-Innes, EnviroHealth Editor, Health24, updated June 2010)

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