Hong Kong air pollution

Phone app to provide real-time pollution levels in the neighbourhood

Smartphone users will be able to get real-time air-quality alerts for their vicinity and advice on whether it would be wise to stay indoors

PUBLISHED : Friday, 06 December, 2013, 6:40pm
UPDATED : Wednesday, 26 October, 2016, 2:38pm

Smartphone users will soon be able to find out how bad the air is where they are living, using an app to be launched at the end of the month.

The app will offer users real-time alerts on air quality in their vicinity and in other districts across the city, and advice on whether they should stay indoors at times of high pollution.

The smartphone app is one of the initiatives from the Environmental Protection Department that alert residents to their level of their exposure to air pollution as air-quality objectives are raised.

With the app's launch on December 30, the city will also replace its 18-year-old air pollution index (API) with the air quality health index (AQHI), which will alert people to the short-term health risk caused by different air pollution levels.

"For example, a sports teacher can plan ahead and consider if he should hold classes outdoors," Andrew Lai Chi-wah, deputy director of environmental protection, said yesterday. "This tool can be a valuable resource for people susceptible to air pollution, as well as the elderly and children. Those working outdoors or planning outdoor activities will also find it useful."

Users of Apple or Android smartphones will input the district they are in and the level of pollution at which they wish to be alerted.

The app will display the AQHI and the concentrations of pollutants including PM10 and PM2.5, recorded at the 14 general and roadside monitoring stations.

PM10 refers to respirable suspended particles - tiny specks of pollutants that can penetrate the lungs and cause cancer - of 10 microns or less.

"Users can also check the data in the past 24 hours and the air-quality forecast, which will be updated twice a day, in the morning and in the afternoon," Pang Sik-wing, principal environmental protection officer, said.

The API converts air pollution data into a value ranging from 0 to 500. The city aims to keep the index at 100 or below, but between 2005 and 2011 there were about 20 days a year when the API shot above 100.

In March 2010, the index was pushed off the 500-point scale for two days when a sandstorm blew in from across the border.

The AQHI, by contrast, analyses the three-hour average concentrations of four major pollutants - ozone, nitrogen dioxide, sulphur dioxide and respirable suspended particles.

Five levels of health risk are defined, with 1 meaning a "low" health risk and 10+ "serious". "As we are going to adopt tighter standards, residents can expect to see more days with the AQHI at high to serious levels," Lai said.

AQHI is used in many Western countries, but Hong Kong would be the first city in Asia to adopt it, the department said.

The Clean Air Network said employing the new index was not enough. It urged the department to work with the labour, health and education departments to line up contingency measures that could be taken on days with serious pollution.

The group also offers an iPhone app that checks real-time data recorded at the 14 monitoring stations.