4. The remaining ALs in Part 2 are defined physical quantities related to the direct biophysical effects of exposure to electromagnetic fields. Employers may, as part of their exposure assessment, assess electromagnetic field levels against these ALs. Each AL table states which ELV or ELVs will be complied with if electromagnetic field levels at a particular frequency do not exceed that AL. Exposures to electromagnetic field levels in excess of the AL may still be below the relevant ELV but the employer will have to undertake further assessment to determine this under regulation 5.