Exposure Variability Between 1‐ or 6‐Minute and 30‐Minute Averaging Time Lengths in Radiofrequency‐Electromagnetic Field Exposure Monitoring

Different averaging time lengths (ATLs) are widely used in radiofrequency-electromagnetic field (RF-EMF) exposure monitoring. This study evaluated variability in RF-EMF exposure associated with the ATLs of 1- and 6-min normalised to 30-min data. For 15 frequency bands of interest, RF-EMF exposures were collected in contiguous 1-min blocks over 30 min at four sites (two outdoor and two indoor). Frequency-band and site-specific variability in exposure between the three ATLs was assessed. First, the variability in terms of relative deviation (in dB) between 1- or 6-min and 30-min were estimated. Second, the overall exposure variability (in μW/m²) were compared between 1- or 6-min and 30-min blocks statistically using the quantile regression method. The overall exposure variability on ATL of 1-min or 6-min was considered different to 30-min if a majority of respective sub-pair comparisons across different percentiles (P₅, P₂₅, P₅₀, P₇₅, P₉₅) were significantly different. The study largely showed that the exposure variability (i.e., relative deviation) of different ATLs was within +/- 3 dB. Further, the overall exposure variability between 1- or 6-min and 30-min ATLs showed inconsistent outcomes. Frequency bands of broadcast and most of the mobile services < 2 GHz demonstrated overall similar exposure variability for 1-min and 6-min ATLs.