A volatile composition dispenser comprising: a) a housing having opposing first and second walls that are joined along their peripheries (22. 24) to one another, wherein said first wall has an aperture and wherein said second wall has a plurality of apertures wherein said aperture cooperates with said plurality of apertures to provide a chimney stack effect, wherein said plurality of apertures have an elongated shape; b) a volatile composition cartridge comprising a membrane; the cartridge further comprising a receptacle sealed by a rupturable substrate, wherein said cartridge is disposed within the housing between said first and second walls; c) a gap, which exists between said cartridge and a bottom surface of the housing, wherein said bottom surface is formed from a joinder of a base portion of one or both (25a, 25b) of the first and second walls, and wherein, upon activation by perforation of the rupturable substrate, the wettable membrane exposure percentage is from 40% to 90%; wherein the wettable membrane exposure percentage is derived by taking the total surface area of the plurality of apertures area divided by the wettable surface area, wherein at least 60% of the total surface area of the plurality of apertures results from individual apertures of said plurality that each have an area of at least 30 mm 2 and an aspect ratio of at least 1:2, wherein said dispenser is activated by a user and wherein thirty days after said activation, the cumulative weight loss of a partially exposed membrane is 70% to 90% of the cumulative weight loss of a fully exposed membrane, wherein the cumulative weight loss of the partially and fully exposed membrane 30 days after activation is calculated using the formula: Cumulative Weight Loss at T 30 days = WcumT 30 days = W Ti − W Tx wherein W Ti = initial weight of the volatile composition (mg) prior to activation; W T30days = weight of volatile composition (mg) at a designated time (30 days) after activation. a) a housing having opposing first and second walls that are joined along their peripheries (22. 24) to one another, wherein said first wall has an aperture and wherein said second wall has a plurality of apertures wherein said aperture cooperates with said plurality of apertures to provide a chimney stack effect, wherein said plurality of apertures have an elongated shape; b) a volatile composition cartridge comprising a membrane; the cartridge further comprising a receptacle sealed by a rupturable substrate, wherein said cartridge is disposed within the housing between said first and second walls; c) a gap, which exists between said cartridge and a bottom surface of the housing, wherein said bottom surface is formed from a joinder of a base portion of one or both (25a, 25b) of the first and second walls, and wherein, upon activation by perforation of the rupturable substrate, the wettable membrane exposure percentage is from 40% to 90%; wherein the wettable membrane exposure percentage is derived by taking the total surface area of the plurality of apertures area divided by the wettable surface area, wherein at least 60% of the total surface area of the plurality of apertures results from individual apertures of said plurality that each have an area of at least 30 mm 2 and an aspect ratio of at least 1:2, wherein said dispenser is activated by a user and wherein thirty days after said activation, the cumulative weight loss of a partially exposed membrane is 70% to 90% of the cumulative weight loss of a fully exposed membrane, wherein the cumulative weight loss of the partially and fully exposed membrane 30 days after activation is calculated using the formula: Cumulative Weight Loss at T 30 days = WcumT 30 days = W Ti − W Tx wherein W Ti = initial weight of the volatile composition (mg) prior to activation; W T30days = weight of volatile composition (mg) at a designated time (30 days) after activation. wherein, upon activation by perforation of the rupturable substrate, the wettable membrane exposure percentage is from 40% to 90%; wherein the wettable membrane exposure percentage is derived by taking the total surface area of the plurality of apertures area divided by the wettable surface area, wherein at least 60% of the total surface area of the plurality of apertures results from individual apertures of said plurality that each have an area of at least 30 mm 2 and an aspect ratio of at least 1:2, wherein said dispenser is activated by a user and wherein thirty days after said activation, the cumulative weight loss of a partially exposed membrane is 70% to 90% of the cumulative weight loss of a fully exposed membrane, wherein the cumulative weight loss of the partially and fully exposed membrane 30 days after activation is calculated using the formula: Cumulative Weight Loss at T 30 days = WcumT 30 days = W Ti − W Tx wherein W Ti = initial weight of the volatile composition (mg) prior to activation; W T30days = weight of volatile composition (mg) at a designated time (30 days) after activation. W Ti = initial weight of the volatile composition (mg) prior to activation; W T30days = weight of volatile composition (mg) at a designated time (30 days) after activation.