Nothing in this act shall be construed as estopping the Commonwealth, or any district attorney or solicitor of a municipality, from proceeding in courts of law or equity to abate pollutions forbidden under this act, or abate nuisances under existing law. It is hereby declared to be the purpose of this act to provide additional and cumulative remedies to abate the pollution of the air of this Commonwealth, and nothing contained in this act shall in any way abridge or alter rights of action or remedies now or hereafter existing in equity, or under the common law or statutory law, criminal or civil, nor shall any provision of this act, or the granting of any plan approval or permit under this act, or any act done by virtue of this act, be construed as estopping the Commonwealth, persons or municipalities, in the exercise of their rights under the common law or decisional law or in equity, from proceeding in courts of law or equity to suppress nuisances, or to abate any pollution now or hereafter existing, or enforce common law or statutory rights. No courts of this Commonwealth having jurisdiction to abate public or private nuisance shall be deprived of such jurisdiction to abate any private or public nuisance instituted by any person for the reason that such nuisance constitutes air pollution.