The environment Management Bureau of the Department of environment and Natural resources, Cordillera administrative region office has been monitoring the PM level in the Baguio Central business district since 2007 using the continuous Automatic ambient air quality monitoring system. This level is to be evaluated relative to the national standard set by the Philippine clean air act of 1999, which define the critical level for annual PM mean at 60 and relative to the global air quality guideline of 2005 set by the WHO. Notwithstanding the practical policy target set above , the epidemiological community is unanimous in stating that there is no scientifically validated “safe” level of exposure to PM10 (or PM2.5) . The WHO AQG of 2005 is meant to set the minimum possible and feasible limit to mitigate against the expected adverse health impacts.