The below graph shows the real-time NO2 (nitrogen dioxide) concentration of an office selected in Sai Ying Pun. This is a pilot project with Arduino-based platform measuring air quality using micro-sensors.

You can compare it with the NO2 concentration recorded at official Environmental Protection Department (EPD) website in Hong Kong, in Central/Western District (Sorry I have no idea how to get real-time data from EPD on web and embed onto my website.

https://www.aqhi.gov.hk/en/aqhi/past-24-hours-pollutant-concentration.html

You can see there is a huge discrepancy between the readings – one major reason is that the EPD readings are taken from stations way above the ground (16 meters) and does not represent the true concentration we are breathing at ground level.

This is where EPD’s air monitoring station at Central and Western District situates – of course it is clean because there is no air pollutant emitters around

This is the surrounding environment where’s the air quality sensors are set up. It is meant to measure how roadside air pollution would affect air quality in the surrounding areas.

Inside the sensor we have a module to capture NO2 concentration in the air. In addition, we have a module to monitor the GPS location of where the sensor situates, and the data will be sent to the server every 15mins. (Photo credit: HKCNews)