A pooling space is a ranked poset P such that the subposet w+ induced by the elements above w is atomic for each element w of P. Pooling spaces were introduced in [Discrete Mathematics 282:163-169, 2004] for the purpose of giving a uniform way to construct pooling designs, which have applications to the screening of DNA sequences. Many examples of pooling spaces were given in that paper. In this paper, we clarify a few things about the definition of pooling spaces. Then we find that a geometric lattice, a well-studied structure in literature, is also a pooling space. This provides us many classes of pooling designs, some old and some new. We study the pooling designs constructed from affine geometries. We find some of them meet the optimal bounds related to a conjecture of Erd