a source of something emits / produces / generates / provides that something & using biomass to produce energy is a source of pollution ->  using biomass to produce energy emits pollution  using biomass to produce energy emits pollution & if something emits something else then that something increases the amount of that something else ->  using biomass to produce energy increases the amount of pollution  using biomass to produce energy increases the amount of pollution & biomass is a renewable resource -> biomass is a kind of renewable resource that increases pollution when used to produce energy