This is helpful and good. So many people live in a Christian bubble in this country. They have no idea there are people who don't believe in god. To them, this is an inconceivable notion.
I think it's possible to open minds to new possibilities simply by saying that god is a nonsensical idea. So don't keep quiet. Tell people where you stand. Say, "There is no god!" and say it loud and often. Say it to priests, cops, judges, doctors, cashiers and housewives. Say it to anyone who tells you that they believe in god.
It doesn't have to be confrontational (though that's fun, too). Just say it. You may end up helping the person more than you know. Once their closet door opens a crack, the light begins to pour in. And that crack may widen, especially if the person has a curious mind.
So say it loud and say it often: there is no god.
PS: I actually made that shirt and wear it proudly.