Many studies have elucidated the possible effects of air pollution/acid deposition on East Asian forest ecosystems. Consequently, in addition to monitoring wet and dry deposition, the Acid Deposition Monitoring Network in East Asia (EANET) has been monitoring soil, vegetation, and inland water in forest areas since 2001 as part of its regular-phase activities. Moreover, catchment monitoring is being promoted as an integrated monitoring effort. In this chapter, the monitoring methodologies used in EANET are introduced and the recent outcomes from regular monitoring and research activities are highlighted according to the Second Periodic Report on the State of Acid Deposition in East Asia, which was based on data from the period 2005 to 2009.