FRIEDMAN ET AL. RESPOND

Clayton et al. respond.

Lusk et al. respond.

We thank Schimek for his thoughtful letter. We agree that the American Association of State Highway and Transportation Officials (AASHTO) encourages bike paths; however, AASHTO’s definition of a bike path is a shared use path for pedestrians, skaters, wheelchair users, joggers, and other nonmotorized users. AASHTO discourages bicycle-only cycle tracks because, as noted by Schimek, AASHTO discou...

Nanotoxicology: Gangwal et al. Respond

Gangwal et al. (2011) addressed an important topic for nanotoxicology about assessing the toxicity of inhaled nano materials by recom mending relevant concentrations for in vitro toxicity testing. Their efforts to select in vitro concentrations based on reported occupational exposure levels of inhaled nano materials are, indeed, laudable. Their under lying conceptual approach is logical, involv...

“Phthalates”: Kelley et al. Respond

PAHs: Choi et al. Respond

A 140 volume 117 | number 4 | April 2009 • Environmental Health Perspectives PAH Exposure doi:10.1289/ehp.0800445 We were very interested to read the article by Choi et al. (2008). The difference between maternal exposure and our own data on actual concentrations of poly cyclic aromatic hydro carbons (PAHs) in the human male fetal liver (Fowler et al. 2008) was striking. Eight of the PAH exposu...