A trigger sprayer for use with a spray system, said trigger sprayer comprising: an articulable trigger , a pump operably connected to said trigger , whereby articulation of said trigger about a pivot from a forward rest position to a rearward dispensing position, under a peak force of 10 to 30 Newtons at 30 partial strokes per minute from said forward rest position to a position one-third of the distance towards said rearward dispensing position, said force being measured 40 mm from said pivot, wherein the sprayer has a reservoir which holds a liquid , whereby articulation of said trigger causes corresponding reciprocation of a piston in said pump, said reciprocation of said piston drawing said liquid from said reservoir , said liquid having a surface tension of 20 to 75 mNewtons/meter, a kinematic viscosity of 8.7 E-4 to 0.0015 Pascal seconds at 25 degrees C , and a dynamic viscosity of 0.87 to 1.15 centipoises at 25 degrees C, said liquid being discharged through a nozzle into particles, wherein (a) said particles comprise a volume ranging from 0.75 to 1.5 ml per full stroke of said trigger , said particles having a Dv particle size distribution of 100 to 150 microns, and/or a Dv particle size distribution of 200 to 300 microns; or (b) said particles comprise from 1.0 to 1.5 ml per full stroke of said trigger , said particles having a Dv particle size distribution of 100 to 320 microns, and/or a Dv particle size distribution of 200 to 650 microns. an articulable trigger , a pump operably connected to said trigger , whereby articulation of said trigger about a pivot from a forward rest position to a rearward dispensing position, under a peak force of 10 to 30 Newtons at 30 partial strokes per minute from said forward rest position to a position one-third of the distance towards said rearward dispensing position, said force being measured 40 mm from said pivot, wherein the sprayer has a reservoir which holds a liquid , whereby articulation of said trigger causes corresponding reciprocation of a piston in said pump, said reciprocation of said piston drawing said liquid from said reservoir , said liquid having a surface tension of 20 to 75 mNewtons/meter, a kinematic viscosity of 8.7 E-4 to 0.0015 Pascal seconds at 25 degrees C , and a dynamic viscosity of 0.87 to 1.15 centipoises at 25 degrees C, said liquid being discharged through a nozzle into particles, wherein (a) said particles comprise a volume ranging from 0.75 to 1.5 ml per full stroke of said trigger , said particles having a Dv particle size distribution of 100 to 150 microns, and/or a Dv particle size distribution of 200 to 300 microns; or (b) said particles comprise from 1.0 to 1.5 ml per full stroke of said trigger , said particles having a Dv particle size distribution of 100 to 320 microns, and/or a Dv particle size distribution of 200 to 650 microns. (a) said particles comprise a volume ranging from 0.75 to 1.5 ml per full stroke of said trigger , said particles having a Dv particle size distribution of 100 to 150 microns, and/or a Dv particle size distribution of 200 to 300 microns; or (b) said particles comprise from 1.0 to 1.5 ml per full stroke of said trigger , said particles having a Dv particle size distribution of 100 to 320 microns, and/or a Dv particle size distribution of 200 to 650 microns. <EOS>