When using the /execute command with the @e part of the command, it will ignore the scoreboard score that is attached to the @e

/execute @e[Particle=1] ~ ~ ~ /particle reddust ~ ~ ~ .1 .3 .1 0 30

yet it acts like it says...

/execute @e ~ ~ ~ /particle reddust ~ ~ ~ .1 .3 .1 0 30