“…For the coefficient (na) in our algorithm, which takes into account the presence of environmental factors influencing the exposure, we use a "Sky View Factor," which is the fraction of the sky visible from a given observation point on the ground, taking into account the obstacles, natural or artificial, covering a variable part of the sky view, and we use also the specific Albedo coefficients for different surfaces to evaluate the reflecting phenomena [5], making an approximation based on the Likert scale of the questionnaire's answers (never = 0% of the period, seldom < 20%, sometimes < 40%, often = 60%, always = 100%).…”