Spectral flux absorbed by a surface, divided by that obtained by that surface area. This shouldn't be baffled with "spectral absorbance". At nighttime, scan the horizon for artificial light resources, for example fires and streetlights, then walk towards the glow of light air pollution. The light was filtered to https://prefabricatedhouse98765.suomiblog.com/the-smart-trick-of-lightweight-steel-frame-houses-that-nobody-is-discussing-54788819