Equivalent Melanopic Lux (EML) is a new method of measuring the spectral characteristics of light, which is important for understanding how it affects human health and wellbeing. EML is a way to quantify the melanopic response of light, which is the way that the eye’s non-visual receptors respond to light and regulate the body’s circadian rhythms. This response is mediated by the hormone melatonin, which is released by the pineal gland in response to changes in light levels.
The melanopic response is different from the photopic response, which is the way that the eye’s visual receptors respond to light and which is used in the traditional measurements of illuminance, such as lux and footcandles. While illuminance is important for visual tasks, it is not necessarily correlated with the melanopic response and the regulation of circadian rhythms.
Research has shown that exposure to the wrong type of light at the wrong time of day can disrupt the circadian system, leading to sleep disorders, mood disorders, and other health problems. It is therefore important to measure and control the spectral characteristics of light in order to promote healthy circadian rhythms and improve overall health and wellbeing.
Why Don’t We Already Use EML?
One of the challenges in measuring the melanopic response is that it is not a simple linear relationship between light levels and melatonin suppression. Instead, it depends on the spectral power distribution (SPD) of the light source, which can be measured using a spectrometer. The SPD is the distribution of the power of the light at each wavelength in the visible spectrum, and it can be used to calculate the melanopic lux, which is a way of quantifying the melanopic response of the light source.
However, calculating the melanopic lux requires complex calculations and specialized equipment, which makes it difficult for many people to use in practice. This is where the EML comes in. EML is a way of simplifying the measurement of the melanopic response by combining the spectral power distribution with the spectral sensitivity of the melanopic receptors in the eye. This produces a single number that represents the melanopic response of the light source.
Research has shown that EML is an effective method of measuring the melanopic response of light sources. For example, a study published in the Journal of Lighting Research & Technology compared the EML values of a range of light sources with the results of a physiological study that measured the melatonin suppression in human subjects exposed to the same light sources. The study found a strong correlation between the EML values and the melatonin suppression, indicating that EML is a reliable predictor of the biological effects of light.
Another study published in the journal Building and Environment compared the EML values of a range of lighting systems in a real-world office environment. The study found that the EML values were strongly correlated with the subjective ratings of the office workers, indicating that the EML values were a good predictor of the visual and non-visual effects of the lighting on human health and wellbeing.
The Importance of EML for All Industries
In conclusion, Equivalent Melanopic Lux (EML) is a new method of measuring the spectral characteristics of light that is important for understanding how it affects human health and wellbeing. Research has shown that EML is an effective method of predicting the biological and non-visual effects of lighting on human health and wellbeing. As a result, it is becoming increasingly important for architects, lighting designers, and other professionals to measure and control the EML values of their lighting systems in order to promote healthy circadian rhythms and improve overall health and wellbeing.