Air-Conditioned Offices

Backgrounds

Regulatory actions related to IAQ are limited, especially in contrast with regulation of outdoor air quality and industrial workplace. Though some guidance has been provided by authorities or organizations on how to better manage IAQ, they are not in a more structured approach for evaluation and control of IAQ. A severe limitation in many countries is the absence of a single governing authority with responsibility for IAQ. The large variation in the data available for different compounds and the concerned adequacy of the database made the use of a standard approach difficult.

In order to set out a practical and valid guideline or standard for IAQ monitoring and assessment, many organizations have conducted studies to identify and quantify occupational health problems related to poor IAQ, such as the US Occupational Safety and Health Administration (OSHA), the US National Institute for Occupational Safety and Health (NIOSH), the American Congress of Governmental Industrial Hygienists (ACGIH), and the World Health Organization (WHO).

Based on the persistence of IAQ studies, different criteria of IAQ satisfaction have been set in different places in the form of regulations or guidelines; and acceptable exposure levels for individual pollutants were suggested for not only industrial workplace, but also for other premises like offices, residential or schools. Those acceptable exposure levels all mainly follow the recommended values from the above said organizations. Besides, the guidelines focus mainly on better IAQ management practices.

IAQ monitoring in offices of Hong Kong

Hong Kong is probably one of earlies cities to set up a comprehensive scheme for a complete IAQ assessment at the government level supplemented with a legislative ordinance . The Hong Kong Environmental Protection Department (HKEPD) commissioned a study on IAQ in offices and public places in Hong Kong aimed to characterize and quantify, and thus to assess the causes of the pollution problems and recommend suitable control strategies. It comprised a questionnaire survey, field sampling and analysis, statistical analysis of the results, and a study on the practice of other countries. Based on its findings and recommendations, in 1999, a draft of ‘Guidance Notes for the Management of Indoor Air Quality in Offices and Public Places (GN)’ was issued on self-regulatory basis. Later, to arouse the awareness and encourage the, the HKEPD has launched an IAQ certification scheme in 2003, laying out a framework on how IAQ could be monitored for the building industry to follow in practice. Besides the steps to certify IAQ of a workplace, it also details the sampling requirements for the indoor pollutant level. It proposed twelve common environmental parameters for IAQ assessment in Hong Kong, including nine major indoor air pollutants as well as three thermally comfort-based parameters. However, those parameters were proposed based on the previous study and recommended levels were set with references to the guidelines and regulations from other countries, including the USEPA, WHO, ACGIH, and Finnish Society of IAQ and Climate, or extended from the Hong Kong Air Quality Objectives under the Air Pollution Control Ordinance (Cap. 311).

Only few regions such as Korea and Japan present the IAQ standard as a regulation, most of them suggest the standard as a guideline. Recently, with reference to Hong Kong experience, Taiwan Environmental Protection Administration also launched a voluntary IAQ program, providing recommended value on 10 parameters, with an assessment period of 1-24 hrs.

IAQ and offices

Currently, inadequate access to official sources specifically for wellness and productivity data for IAQ in Hong Kong is available. Some occupational safety and health statistics from the Labour Department would be found useful.

Further information

Wong LT, Mui KW, 2009. Efficiency assessment of indoor environmental policy for air-conditioned offices in Hong Kong, Appl Energy 86(10) 1933–1938.

Kosonen R, Tan F, 2004. Assessment of productivity loss in air-conditioned buildings using PMV index, Energy Build 36 (10) 987–993.

Clausen G, Wyon DP, 2008. The combined effects of many different indoor environmental factors on acceptability and office work performance, HVAC&R Res 14 (1) 103–113.

Haghighat F, Donnini G, 1999. Impact of psycho-social factors on perception of the indoor air environment studies in 12 office buildings, Build Environ 34 (4) 479–503.

Enquiry: Dr. PS Hui

Some problems I have encounted and therefore I have investigated ...

• IAQ at air-conditioned offices of Hong Kong: the past, now and estimates for future

• Can we better estimate for the regional situation when we have insufficient data?

  • How long I should sample for an IAQ parameter? A question of sampling scheme vs uncertainties ...

  • How a Bayesian approach can help to improve the measurement accuracy, with some alternative measurement approaches?

  • How many sampling location(s) required?

• Would professional judgement help in determining the sampling location(s)?

  • What parameters we are going to monitor?

• Airborne fungi counts - the 13th IAQ assessment parameter?

• Dilution as a means of IAQ improvement

Measurements of example parameters in some air-conditioned offices of Hong Kong in additions of air temperature, relative humidity and air velocity ...

Radon, CO, Ozone, CO₂, HCHO, PM₁₀, TVOC, NO₂, Airborne bacteria counts, Airborne fungi counts and their compositions

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South China Morning Post (23/2/2006)

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Workplace - RFP Magazine (2009)