The field survey were lasted for a whole year long, from January of 2009 to January of 2010, and interrupted for several weeks
intermediately for summer and winter holidays. Some data were
missing due to the absence of subjects and finally 1395 sets of raw
data in 33 weeks were obtained. The collected data were categorized
as data set of spring (1ste11th week), summer (12the21st
week), autumn (22nde32nd week) and winter (33rd week)
according to the season division of Guangzhou [3] (see Table 3)