“…Flow cytometric analysis was performed with a FACScan flow cytometer as described previously (Li et al, 2007a(Li et al, , 2007b(Li et al, , 2008a(Li et al, , 2008bLi, 2010b). Investigation of human physiological responses in actual field sites is extremely valuable because it can reveal the total effects of the surrounding environment (Lee et al, 2009(Lee et al, , 2011b(Lee et al, , 2011cMatsunaga et al, 2011;Park et al, 2007Park et al, , 2008aPark et al, , 2008bPark et al, , 2009Tsunetsugu et al 2007b). A field study provides more important information regarding the effects of real environments than an indoor study.…”