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Microlevel activity time series (MLATS) data were gathered on hand contact activities of 38 children (1–6 years old) by videotaping in primarily outdoor residential environments. The videotape recordings were then translated into text files using a specialized software called VirtualTimingDevice™. Contact frequency (contacts/h), duration per contact (s/contact), and hourly contact duration (min/h) were summarized for outdoor hand contacts with 15 distinct object/surface categories (“Animal”, “Body”, “Clothes/Towels”, “Fabric”, “Floor”, “Food”, “Footwear”, “Metal”, “Non-dietary Water”, “Paper/Wrapper”, “Plastic”, “Rock/Brick”, “Toys”, “Vegetation/Grass”, and “Wood”) and two aggregate object/surface categories (“Non-dietary objects/surfaces” and “Total objects/surfaces”). For outdoor both hand contacts with “Total objects/surfaces”, contact frequencies ranged from 229.9 to 1517.7 contacts/h, median durations/contact ranged from <1 to 5 s, and hourly contact durations ranged from 42.6 to 102.2 m/h.The data were analyzed for significant differences in hand contact activities as a function of (1) age, (2) location, (3) gender, and (4) hand. Significant differences (P0.05) were found for all four factors analyzed. Hourly contact durations with “Non-dietary objects/surfaces” and “Total objects/surfaces” increased with age (P=0.01, rs=0.42 and P=0.005, rs=0.46, respectively), while contact frequencies and hourly contact durations with “Wood” decreased with age (P=0.02, rs=−0.38 and P=0.05, rs=−0.32, respectively). Location was found to affect contact frequencies and hourly contact durations with certain objects/surfaces. For example, contact frequencies and hourly contact durations with “Fabric” were higher indoors (P=0.02 for both), while contact frequencies and hourly contact durations with “Vegetation/Grass” were higher outdoors (P=0.02 and P=0.04, respectively). Girls had longer hourly contact durations with “Footwear” (P=0.02), “Non-dietary objects/surfaces” (P=0.03), and “Total objects/surfaces” (P=0.01) than boys. The right hand had longer hourly contact durations with objects that are often manipulated with the hand (e.g., “Toys” (P=0.0002)), while the left hand had longer hourly contact durations with passively touched objects/surfaces (e.g., “Clothes/Towels” (P=0.003) and “Floor” (P=0.04)).Journal of Exposure Science and Environmental Epidemiology (2006) 16, 434–446. doi:10.1038/sj.jes.7500480; published online 22 March 2006 [ABSTRACT FROM AUTHOR]