Do not underestimate indoor pollution exposure, think tank warns

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Government index fails to measure indoor pollutants which can be as lethal as their outdoor counterparts.

Photo: Zhi Ning (left) and Simon Ng (right) discuss the findings of their research at a press conference held by Civic Exchange.

Credit: Jasmine Lee

On 8 June, Civic Exchange released the latest research on pollution exposure in Hong Kong. Speakers Zhi Ning (Assistant Professor at City University of Hong Kong) and Simon Ng (Civic Exchange Fellow) presented their findings and other observations and considerations at the press conference.

Civic Exchange and the City University of Hong Kong designed a project under the name “Monitoring Personal Exposure to PM2.5  in Hong Kong with Next Generation Sensors”, in which participants used a device called the Personal Exposure Kit (PEK) to track one’s exposure to certain pollutants in different environments. PM2.5  refers to particulate matter that measures less than 2.5 macrons in diameter, which is one-thirtieth of a human hair. These particles have been associated with lung diseases including cancer, and cardiovascular disease. The goal of this study is to address the current limitations of the Air Quality Monitoring System (AQMS).

According to Ning and Ng, the PEK method is not meant to replace the AQMS but to act solely as supplementary tools that can help improve the system already in place.

The revolutionary PEK is a portable lunchbox-sized sensor that is not only able to measure the amount of pollutants in the air, but is also able to transmit and record data in real-time. These devices are able to detect and differentiate amongst commonly frequented environments, indicating whether the data is coming from an office, home, school, or an outdoor area. This is due to configurations such as a noise sensor, light sensor, temperature and humidity sensor, that allow the device to effectively contextualise the data in its proper space and time.

This study consisted of 73 participants and took place from December 2015 to May 2016, in which the participants carried the PEK with them for 24 hours for several days at a time. The results from the volunteers showed that PM2.5 exposure were much higher than the recordings indicated by the government’s Air Quality Health Index (AQHI). The AQHI readings are based off of 16 fixed stations that measure outdoor pollutants, but not exposure to indoor nor individual pollution.

Ning and Ng warned that while the focus on outdoor air quality is important, indoor air quality (IAQ) should receive the same level of attention. Research indicates that Hong Kongers were exposed to high levels of pollutants when indoors, and found that it was particularly worse in homes in comparison to the office and transportation. This is of major concern as the study volunteers spent more than 85% of their time indoors.

While the information may seem alarming, the researchers ensured that they are not encouraging people to move out of their homes. At the press conference, Ng said: “This is something that we believe can provide more information for every one of us to make the right decision every day. If we want to go somewhere and do something, before making that decision we can basically check exposure levels like a forecast and then we decide, should we go, should we do it?” They recommended that the government inform the public on pollution exposure in the household, that there are stricter regulations to improve air quality standards, and that more larger-scale studies should be conducted on Hong Kong’s individual pollutant exposure.

In regards to the PEK itself, next steps include releasing an improved version of the device, which Ning claimed will be the size of a smartphone, or even as small as a cigarette box.

One can access the full report, “Monitoring Personal Exposure to PM2.5 in Hong Kong with Next Generation Sensors”, online at this link.

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