How Do LED Lights Work?

LED lighting products work much like standard lights, except for the fact that LED lights are much smaller and contain no filament and harmful gases. Instead of a filament and gas, an LED creates light using nothing but the movement of electricity along the path of its semiconductor. As the electrons stream across the semiconductor, they create electromagnetic radiation. Some forms of this electromagnetic radiation can take the form of visible light. There are no harmful gases such as mercury used in the production of LED lights, as opposed to the toxic levels that are used in all the other different light sources.

How Do Fluorescent, Sodium, Halogen and Metal Halide Lamps Work?

A fluorescent lamp or fluorescent tube is a gas discharge lamp that uses electricity to stimulate mercury vapor. The stimulated mercury atoms produce short-wave ultraviolet light that then causes a phosphor to fluoresce, producing visible light. A fluorescent lamp changes electrical power into light more efficiently than an incandescent lamp.

There is also a Sodium vapor lamp that is a gas discharge lamp which uses sodium in an agitated state to produce light. There are two varieties of these lamps: low pressure and high pressure.

Low-pressure sodium (LPS) lamps have borosilicate glass gas discharge tubes (arc tube) containing solid sodium and a small amount of neon and argon gas to start the gas discharge. When the lamp is turned on it emits a dim red/pink light to warm the sodium metal and within a few minutes it turns into the common bright yellow as the sodium metal vaporizes.

High-pressure sodium (HPS) lamps are smaller and contain extra elements such as mercury. They produce a dark pink glow when first struck.

Metal halide lamps are a member of the high intensity discharge (HID) family of lamps and they produce high light output for their size. This makes them a dense, potent, light source. By adding rare earth metal salts to the mercury vapor lamp, improved luminous efficacy and light colour is obtained.

A halogen lamp is an incandescent lamp with a tungsten filament contained within an inert gas and a small amount of a halogen such as iodine or bromine. The combination of the halogen gas and the tungsten filament produces a chemical reaction known as a halogen cycle.

The incandescent light bulb, incandescent lamp or incandescent light globe is a source of electric light that works by incandescence. An electric current passes through a thin electrical filament, heating it to a temperature that produces light. The enclosing glass bulb contains either a vacuum or an inert gas to prevent oxidation of the hot filament.

Harmful Effects

All mercury vapor lamps (including metal halide lamps) must contain a feature (or be installed in a fixture that contains a feature) that prevents ultraviolet radiation from escaping. Usually, the borosilicate glass or outer bulb of the lamp performs this function, but special care must be taken if the lamp is installed in a situation where this outer case can become damaged. There have been documented cases of lamps being damaged in gymnasiums by a ball hitting them and sun burn and eye inflammation have followed as a result. When used in locations like gyms, the fixture should contain a strong outer guard or an outer lens to protect the lamp's outer bulb. Also, special "safety" lamps are available that will deliberately burn out if the outer glass is broken.

Even with these methods, some UV radiation can still pass through the outer bulb of the lamp. This causes the aging process of some plastics used in the construction of luminaries to be accelerated, leaving them significantly discolored after only a few years of service. Polycarbonate suffers particularly from this problem, and it is not uncommon to see fairly new polycarbonate surfaces positioned near the lamp to have turned a dull, 'ear-wax'-like color after only a short time. It is important to note that if the polycarbonate is being damaged what is the UV radiation doing to people that are under these lights all day and night? It has been suggested that the effects have caused tumors in lab animals.

Exposure to mercury vapor can occur through inhalation, eye or skin contact. The effects on humans are as follows. Mercury vapor can cause effects in the central and peripheral nervous systems, lungs, kidneys, skin and eyes. It is also a mutagenic and affects the immune system [Hathaway et al. 1991; Clayton and Clayton 1981; Rom 1992]. Acute exposure to high concentrations of mercury vapor causes severe respiratory damage, while chronic exposure to lower levels is associated with central nervous system damage [Hathaway et al. 1991]. Chronic exposure to mercury is also associated with behavioral changes and alterations in the nervous system.

With all fluorescent, sodium, halogen and metal halide lamps containing mercury and other harmful metals and gases it is important to note the effects of exposure to the mercury vapor. We know that LED lighting products are a safe alternative to mercury lights and UV radiation from lights.

The life cycle of an LED light is 10 times longer than mercury lighting, and for this reason the LED’s light will last a house hold a life time, as opposed to the alternative mercury lighting, that will fade then need to be installed by a qualified electrician and discarded of by added to our ever increasing waste deposits.

End of Life and Waste of Fluorescent, Sodium and Halogen Lamps

Mercury vapor lamps rarely burn out completely and suffer drastically from lumen depreciation (light output). The lamp produces 50% less light every five years, to the point of becoming ineffective while still drawing the same amount of power it drew when it was new. This happens because the emitter is deposited as a film, darkening the arc tube wall and reducing light output.

When discarding a fluorescent tube, the main concern is the mercury, which is a dangerous pollutant.

A broken fluorescent tube will release its mercury content into the atmosphere, and be inhaled by others. Safe cleanup of broken fluorescent bulbs differs from cleanup of conventional broken glass or incandescent bulbs, 99% of the mercury is typically contained in the phosphor, especially on lamps that are near their end of life.

The disposal of phosphor and particularly the toxic mercury in the tubes is an environmental issue. Governmental regulations in many areas require special disposal of fluorescent lamps separate from general and household wastes.

Only a few tenths of a milligram of mercury are required to maintain the vapor, but lamps must include more mercury to compensate for the part of mercury absorbed by internal parts of the lamp and no longer available to maintain the arc.

By changing to energy efficient lighting with LED lighting products, you save financially in the short and long term, plus, you are assisting the environment by not adding harmful gases into the atmosphere and not adding to our waste deposits. You also save on the maintenance that is required for conventional mercury light sources from a qualified electrician.

Make the change to a bright start.