Photomask lifetime has become a challenge since the introduction of high volume manufacturing 193nm photolithograph. Photomask lifetime is being impacted by a broad range of environmental and process factors resulting in inorganics crystals and organic contaminants formation as well as pellicle lifetime issues. Extensive work has been published on strategies for reduction of inorganic crystals photoinduced defects formation mainly focusing on photomask clean process improvements. This paper will focus on identifying root causes for photoinduced contaminants forming within the pellicle space area as well as identify environmental factors which have the potential of impacting pellicle membrane longevity. Outgasing experiments coupled with 193nm laser exposure tests were conducted to decouple and rank reticle/pellicle storage materials as well as pellicle outgasing contributors to photoinduced defects and identify factors impacting pellicle membrance longevity. Analytical test were conducted to compare the relative levels of reticle storage materials and pellicle outgasing contaminants. Experiments aimed at quantifying the fab environment contribution to photoinduced defects formation and impact on pellicle membrane lifetime will be discussed. Environmental conditions minimizing external contributing factors impacting photomask front side photoinduced defects formation and pellicle membrance longevity will be suggested.