Sensor technology breakthrough in air pollution health risk mitigation

PRAISE-INSIGHT
Leveraging new sensor technologies to mitigate exposure risk from air pollution
By Prof. Zhi NING, Associate Professor of City University of Hong Kong; Project Consultant of PRAISE-HK.


Air pollution is a global health risk that has a particularly marked impact on people living in densely populated cities like Hong Kong. For a long time, much of the pressure has been laid on the government to clean up the air. And indeed, over the last decades, we have seen a decline in air pollutants levels in Hong Kong thanks to a series of measures taken by the local government, including the mandatory fuel switch at berth for ocean going vessels and the phasing out of Pre-Euro IV diesel commercial vehicles, orchestrated with neighboring governments in a rigorous effort to control source emissions.[1]

With the outdoor air becoming clearer and cleaner, are we reaping corresponding health benefits? Based on our recent study by City University of Hong Kong and Civic Exchange[2], it seems that the answer is not so clear cut.

Study reveals need for paradigm shift in air pollution management

The study, which continuously tracked the individual activities of a group of 73 volunteers, showed that exposure profiles (to fine particles PM2.5) varied greatly among individual participants due to variety in their home locations, commuting patterns, and personal lifestyles including weekend activities. The study showed mean PM2.5 concentrations on weekdays varying from 13μg/m3 (office), 42.5μg/m3 (home), 40.4μg/m3 (commuting), 52.6μg/m3 (office) to 54.4μg/m3 (outdoor).

As in many other similar surveys, the volunteers spent about 85% of their time indoors every day. The study revealed that PM2.5 levels recorded from the participants’ homes varied in the biggest magnitude compared to other indoor environments such as offices, homes, shopping malls, and restaurants. This variation is very likely a consequence of the variety of personal activities conducted at home, such as cooking, cleaning or even smoking.

The study’s findings call for a better understanding among researchers and policymakers on how outdoor air pollutants can enter indoor spaces and affect daily exposure risks. This study also demonstrates that exposure to air pollutants is heavily determined by the choice of personal activities.

Portable sensors can reveal relationship between personal activities and exposure 

While the government’s 16 existing stationary air quality monitoring stations have been providing important reference data, emerging fast-response and low cost sensor technologies are now making it possible to accurately capture and compare individuals’ exposure to pollutants in different indoor and outdoor microenvironments (home, office, schools, on the streets, while commuting, etc.). This will allow us to understand in finer detail how air pollutants are distributed around us.

The latest innovative advancements related to air quality have also included sensors for other major gaseous pollutants such as nitrogen oxides, ozone and carbon monoxide. These cutting-edge technologies have a wide range of applications, among them a detailed investigation of how outdoor air pollutants enter indoor environments. This is expected to drive a paradigm shift in air pollution exposure management, and pave the way for further discoveries that will enable individuals to make healthier personal choices and policymakers to develop future solutions.

[1] http://www.enb.gov.hk/sites/default/files/CleanAirPlanUpdateEng_W3C.pdf

[2] http://www.ninglab.org/upload/Cex_PM2_5%20report_FINAL.pdf