The Environmental Protection Department has refuted a newspaper report comparining of the results of seven local air quality monitoring locations and the US standard.

The department said the report is premised on a misunderstanding of the purpose and parameters of the study on Determination of Suspended Particulate & Volatile Organic Compounds Emission Profiles for Vehicular Sources in Hong Kong, released in July.

The study was to enhance the understanding of and improve the assessment methods for vehicle emissions, and its findings have confirmed many of the current understandings on emissions in Hong Kong and the validity of methods used to assess them.

The department said out of the six monitoring locations, three were inside road tunnels and three were at the roadside, but the US PM2.5 standard is applicable only to general outdoor air. For the general outdoor air samples collected in the same study, the PM2.5 concentrations were actually below the US standard.

The study also found the emissions of various pollutants in tunnels are generally lower than in other countries. This reflects that the local vehicle emission control programme is successful.

The department said it will consider the need for revising Hong Kong's Air Quality Objectives from a scientific perspective and local applicability, by making reference to the results of reviews in the US, Europe and other developed countries, in conjunction with information obtained from ongoing local studies.