Monitoring Personal Exposure to PM2.5

In June 2017, Civic Exchange published a report on “Monitoring Personal Exposure to PM2.5 in Hong Kong with Next Generation Sensors.” To download the report, click on the above PDF icon.

Key Findings

  • Our volunteers’ PM2.5 exposure were generally much higher than readings by the nearest government air monitoring station. Hong Kong may be significantly underestimating its residents’ true pollution exposure risk.
  • Our volunteers’ PM2.5 exposure during commuting exceeded limits set by the World Health Organization (WHO). However, they fell within Hong Kong’s own Air Quality Objectives, which are more less stringent.
  • Time at home made up about half of the volunteers’ time over a 24-hour period, and reached 81% during weekends. In total, the volunteers in this study spent more than 85% of their time indoors – including at home, at work, and other indoor environments.
  • PM2.5 exposure at home was significantly higher than in the office, and even slightly higher than on transportation.
  • Pedestrians, in particular, were consistently exposed to about double the WHO’s recommended limit of PM2.5 exposure.


  • The Government should inform the public on pollution management in households, given the high level of PM2.5.  In May 2017, the Environmental Protection Bureau launched a series of Cantonese, Putonghua and English videos on the issue, which Civic Exchange welcomes as a good first step.
  • Hong Kong’s official Air Quality Objectives should be tightened to meet WHO standards.
  • More studies should be conducted on individual pollutant exposure, using a much larger and more varied body of volunteers than this initial pilot study.
  • New generation sensors should be developed into something smaller, lighter, and capable of providing real-time or personalized data to the individual.

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