Personal PM 2.5 exposures of husband and wife by residential characteristics in Ulaanbaatar, Mongolia

In Ulaanbaatar, Mongolia, coal combustion in the ger area is the main source of indoor and ambient air pollution that contributes significantly to residents’ health. It was critical to characterize personal exposure to PM 2.5 to help prevent adverse health effects from indoor coal burning. This study compared personal exposure to PM 2.5 between ger and apartment residents and evaluated the influence of time-activity patterns. Two-day personal exposure of 16 couples from gers and 16 couples from apartments in Ulaanbaatar, Mongolia, was measured in January and February 2019. A portable monitor (ASLUNG, Rododo Science, Taipei, Taiwan) was used to measure real-time personal PM 2.5 exposure, and information on participants’ time-activity patterns was recorded in a logbook. Ger residents were exposed to a significantly higher PM 2.5 concentration (59.1(1.7) μg/m 3 ) than apartment residents (26.8(2.0) μg/m 3 ). However, the personal exposure of couples in gers and apartments was not affected by the time-activity pattern. The ambient PM 2.5 concentration was higher than the personal PM 2.5 exposure of ger and apartment residents. Daily personal PM 2.5 exposure profiles of all residents showed a sharp increase at 8:00 a.m. and a decrease after dawn. For all residents, the largest personal PM 2.5 exposure was at home. National measures to reduce ambient PM 2.5 concentrations are necessary for the reduction of personal PM 2.5 exposures of Ulaanbaatar residents.