Ruth is a lighting consultant with a background in engineering, lighting design and academia. She’s passionate about the role of daylight and sunlight in bringing buildings to life, and the impact of daylight exposure on the health and wellbeing of building occupants. Ruth,  Michael and Greg discuss the challenges of measuring negatives and positives.  That is, you can measure the effects of taking away flicker or blue light, but how do you measure the effects of improving people’s health with human centric lighting or air purification?