Air quality monitoring stations are located throughout the country. The Department of Environment Natural
Resources (DENR) operates a network of 44 air quality monitoring stations in 15 regions. The Manila Observatory
(MO), a private scientific institution, and the Philippine Nuclear Research Institute (PNRI) of the Department of
Science and Technology (DOST) also monitor air quality. PNRI monitors PM10 and PM2.5 using the Gent sampler at
three sites in Metro Manila. MO monitors PM2.5 using air samplers at New Year’s Eve since 2003 in Metro Manila