One man's bid to map haze here through crowdsourcing

Carolyn Khew The Straits Times AsiaOne 12 Oct 14;

The idea is to get many people all over Singapore to buy a sensor kit and place it in their homes so as to map the haze when it hits the country.

This, in theory, could help people decide on their outdoor activities, said software engineer Roland Turner, 44, who started the crowdsourcing project in June.

So far, 17 people - mostly friends of Mr Turner - have bought the portable haze sensor kit. He hopes to get 50 to 60 participants by December.

"My objective for the project is to have enough sensor data to make it possible to understand how haze propagates in Singapore," said Mr Turner, an Australian living in Singapore.

But the kit is still a work in progress, he said.

For one thing, its sensor counts the air particles detected, instead of weighing them, so readings may not entirely reflect haze particles.

Mr Turner also stressed that the project does not aim to replace the haze data from the National Environment Agency (NEA).

When contacted, NEA said it is unclear how the kit's sensor will count only PM2.5 particles - an air pollutant associated with the haze that is less than 2.5 microns in size - and not larger ones.

Moisture interference may also affect the readings, it said.

The kit is likely to pick up only big particles such as dust and bacteria, said Assistant Professor Jason Cohen from the National University of Singapore's civil and environmental engineering department.

Research scientist Erik Velasco, from the Centre for Environmental Sensing and Modeling at the Singapore-MIT Alliance for Research and Technology, said environmental agencies follow very strict procedures based on international monitoring standards when it comes to tracking air pollution.

"Initiatives like (Mr Turner's) are good because they show society's concern about a problem," he said.

But he cautioned that such projects could lead to misinformation if they are not scientific and well-designed.

Mr Turner's kit contains a dust sensor similar to those used in air purifiers. It detects air particles via infrared light.

The live data collected by the kit is combined with previously recorded readings from the kit and PM2.5 readings from the NEA before it is converted to estimated PM2.5 readings.

These readings are updated every 30 seconds and displayed on a real-time map of Singapore as colour-coded circles indicating the air quality.

Locations that have been mapped so far include Novena and Upper Bukit Timah.

Each kit costs $95 and Mr Turner said the money goes to a technology company that supplies the parts.

Improvements to the kit and its readings are under way, he said.

"Scientists, educators and data visualisation specialists are starting to get involved," he said, adding that he welcomes the participation of environmental scientists.

Despite the kit's shortcomings, participants such as tech firm partner Ciaran Lyons, 37, think the project is a "great first step" towards a low-cost, people-led network of sensors to map the haze.

"As the sensors improve, so too will the network's capabilities," he said.