Дані про якість повітря надано: the Vietnam Center For Environmental Monitoring Portal (cổng thông tin quan trắc môi trường) (cem.gov.vn)
News (Jan 2016): AQI Station from UNIS (United Nations International School Of Hanoi) is now available for Hanoi.
News (Jan 2016): The readings for the Hanoi CEM Station are abnormally low, so the PM2.5 AQI calculation has been again re-adjusted by a factor of 30 to reflect the current conditions.
News (Dec 2015): Due to many message received about the Hanoi monitoring station is reporting abnormally low values (since December 21th, 2015), the AQI calculation for Hanoi is adjusted to reflect the current conditions. Check this blog entry for more information about this case.