Air Quality

Air Quality

The AA is committed to complying with statutory air quality criteria and monitoring and controlling air emissions associated with airport operations.

As one of the world’s busiest airports, Hong Kong International Airport (HKIA) manages emissions from its daily operations through a range of policies, reduction measures and continuous monitoring with the aim of minimising impact on the community and the surrounding environment.

Our Story

Air Quality Monitoring

The AA has been monitoring the air quality at HKIA since 2004 and has made this information available on its website since 2012. The data helps to identify the most cost-effective policies and solutions to reduce emissions at HKIA and also provides useful insights into regional air quality. Ambient air quality at HKIA is monitored through two on-airport air quality monitoring stations and a control site on Sha Chau. Monitored air pollutants include nitrogen dioxide (NO2), sulphur dioxide (SO2), respirable suspended particulates (PM10), fine suspended particulates (PM 2.5), Carbon Monoxide (CO) and ozone (O3). The average hourly concentrations are collected and disclosed in real-time to the public on our website.

In 2016, we upgraded our website to include hourly Air Quality Health Index (AQHI) information, which makes reference to the AQHI published by the HKSAR Government.

Air Quality Management

The AA is committed to reducing air emissions that are under our direct control (e.g., emissions related to AA vehicles), and facilitating emissions reduction of airport business partners and aircraft at parking stands.


Aircraft at parking stands normally use their Auxiliary Power Units (APUs), which are small engines located at the rear of aircraft, to provide electrical power when the main engines are switched off. To reduce emissions from burning jet fuel, the AA implemented an APU ban in December 2014 that controls the use of APUs at frontal stands. In order to meet aircraft’ needs for electrical power and cabin cooling when parked, the AA installed fixed ground power (FGP) and pre-conditioned air (PCA) systems - a total of 296 FGP units and 150 PCA units. The AA also worked closely with our airport business partners to organise trials and develop operational procedures for the transition.

Airside Vehicles

All vehicles driven within the Airport Restricted Area (ARA) are required to obtain an Airside Vehicle Licence (AVL) issued by the AA. All airside vehicles must comply with stipulated emission standards. Since July 2013, the AA has required all newly registered saloons operating in the ARA to be electric vehicles (EVs); and since July 2017, all saloons on the airside must be EVs. To facilitate the transition, the AA installed 242 EV chargers including 194 normal EV chargers, 14 quick chargers and 34 electric Ground Service Equipment (GSE) chargers on the apron. The network is planned to be expanded to 500 chargers by the end of 2020.

Ground Services Equipment (GSE) Pooling Scheme

In July 2018, HKIA rolled out the On-stand GSE Pooling Scheme at the Midfield Apron as a resource-sharing initiative to unleash existing untapped capacity and create new capacity in the ramp handling process, and to lower the emissions generated by the equipment.

The on-stand GSE provided included electric lower deck loaders, electric conveyor belt loaders, electric passenger steps and main deck loaders. Subject to ramp handlers’ request, electric baggage tractors and powerful tractors are also available for rental, 95% of which were either electrically-powered or of zero-emission. 

Subsequent phases of the scheme will expand the coverage to other areas of the airport: Terminal 1 Apron and the future Third Runway Concourse Apron.

Air quality study with HKUST

Since 2007, the AA has worked with Professor Alexis Lau, Dr Li Ying and other experts at the Hong Kong University of Science and Technology (HKUST) to analyse air quality data and study HKIA’s operational air quality impact. HKUST conducted the following two studies in 2014/15:

Airside Vehicle Emissions Inventory

In 2014, HKUST completed a baseline inventory of air pollutant emissions associated with HKIA’s operations in 2011. The study focused on emissions from airside vehicles and GSE. The findings helped to identify the best opportunity for emissions reduction: accelerating the retirement of aged diesel vehicles and replacing them with EVs or other low emission vehicles.

Aircraft-related Emissions Inventory

In 2014, HKUST began a study on emissions associated with the aircraft LTO cycle below 3,000 feet. This included analyses of the emissions from different phases of the LTO cycle and the mix of CAEP* aircraft engine emission standards. The study findings have provided grounds for further investigation of potential emission-reduction control measures for aircraft on the ground, such as reduced-engine taxiing.

Landside Traffic and Ferry Emission Inventory

In 2015/16, HKUST commenced investigations into emissions associated with landside vehicles to establish an emission inventory for this source. In the coming years, HKUST will also review ferry emission data to develop an approach for managing ferry emission inventory.

* The CAEP standards refer to the aircraft engine emission standards set by International Civil Aviation Organization’s Committee on Aviation Environmental Protection. The higher the CAEP number, the better the aircraft emission performance.

The report on Airport Operational Air Quality Study is available here.

The AA will continue to collaborate with HKUST to develop emission inventories for landside transport and marine vessels.

Quick Facts  


Since July 2017, all saloon vehicles on the airside are required to be EVs


The AA implemented an APU ban in December 2014


The APU ban policy reduces NOx emissions from APU operations by approximately 20%


Six types of air pollutants are monitored at HKIA : nitrogen dioxide (NO2), sulphur dioxide (SO2), respirable suspended particulates (PM10), fine suspended particulates (PM2.5), Carbon Monoxide (CO) and ozone (O3)
Air Quality Data

Current Pollutant Concentration & AQHI


AQHI 24 Hrs


Past 24 hours Pollutant Concentration & AQHI


AQHI Distribution


Download Pollutant Data