Spectrally resolved actinic flux and photolysis frequencies of key species within an indoor environment

Impact of the spectral and spatial properties of natural light on indoor gas-phase chemistry: Experimental and modeling study

“…Calculations based on Fresnel's equations, comparisons between simulations and laboratory measurements, including those made in the framework of the European project ADOPT, and measurements within a real room show that the transmittance decreases when the incidence angle increases.…”

“…An empirical relationship to directly calculate indoor actinic fluxes for a given room from the TUV spectrum as a function of the solar zenithal angle using an architectural model has been proposed . However, as shown above, the type of window will strongly affect the transmittance and therefore needs to be taken into account.…”

“…These differences can be due to differences in the windows and also to the variation in the distance of point of measurement from the windows. The spatial variation of light intensity in the room has also been studied . Comparison between measurements and the output of an architectural model representing the distribution of light has been carried out in one specific room under clear sky conditions and in a classroom under variable conditions, showing relatively good agreement.…”

“…Previous works report the influence of the window composition, the applied coatings, and the solar angle on the characteristics of the light transmitted by windows such as the cutoff wavelength of the windows and their transmittance. In some studies, more specifically dedicated to the evaluation of indoor photochemistry, the ratio of light irradiance between indoors and outdoors has been obtained in different buildings. Large differences in UV light (300‐400 nm) and visible light (400‐760 nm) available indoors were observed varying from 0.15% to 30% and 0.7% to 80% of the outdoor light, respectively.…”

Impact of surface ozone interactions on indoor air chemistry: A modeling study

“…Such values must then be attenuated to be representative for indoors. Although there is limited information in the literature, recent measurements have shown that while light at the visible wavelengths needed to photolyze NO 2 and HONO is typically attenuated to 10%‐15% of that outdoors, for species photolyzed in the UV (such as ozone to give excited oxygen state atoms), transmission is typically <1% of that outdoors. Nazaroff and Cass found that 0.7% and 0.15% of visible and UV light, respectively, were transmitted through museum skylights and 0.15% in the UV, while for two laboratories in Greece with large windows, 70%‐80% of the visible light was transmitted indoors compared to 25%‐30% in the UV .…”