Complex sentence: Aerosols released during this phase are primarily based on concrete-originating silicon compounds; otherwise volatile elements, for example, caesium, can be bound in nonvolatile insoluble silicates.
Split into simpler sentences: Aerosols released during this phase are primarily based on concrete-originating silicon compounds. Otherwise volatile elements, e.g. caesium, can be bound in nonvolatile insoluble silicates.