Chapter 4 : Healthy Indoor Air Environment


A hotel is a place for visitors to rest and relax. A comfortable and healthy indoor environment is a prime quality for a hotel and a prerequisite for visitors’ satisfaction during their stay. Unfortunately, indoor air can sometimes be more polluted than outdoor air. Potential health risks associated with indoor air are increased because of the amount of time spent indoors.

Indoor air quality (IAQ) is an important factor in the hotel industry’s goal for customer comfort. This section is geared towards keeping your guests satisfied by identifying common pollutants found in hotels and describing steps to eliminate those pollutants from your hotel. Improved indoor air quality can result in higher productivity, fewer lost working days and, most importantly, better business through increased customer’s satisfaction.


Factors Contributing to Indoor Air Quality


IAQ problems and concerns have increased tremendously in the last decade. The following combination of factors has contributed to their increase :


• Changes in building construction and heating, ventilation and air conditioning (HVAC) practices have created tighter buildings with fewer operable windows.


• In many buildings, occupants depend totally on the building VAC system to provide adequate ventilation.


• The use of synthetic materials and fabrics in building construction and renovation has become common place.


• Personal care products, cleaners and pesticides are increasingly made of new and sophisticated chemical formulations, often packaged in aerosol cans or spray bottles to facilitate their delivery.

(Photo 4.2) A good ventilation and air conditioning system is needed to provide adequate ventilation. (Photo 4.1) Improved indoor air quality can result in better business through increased customer satisfaction.

 


Thermal acceptability and air pollutants affect the overall indoor air quality. Thermal acceptability is determined by three factors: temperature, humidity and air movement.


Air temperature is influenced by such factors as the temperature setting of the air-conditioning system, intensity of direct sunlight, other heat sources such as lighting, electrical equipment, computers, etc. Too high a humidity level will discourage perspiration yet encourage the growth of undesirable mildew and other fungi on building fabrics and furnishing. Too low a humidity level will, however, cause irritation of eyes, nose and throat and even discharge of static charges, which is uncomfortable for occupants and can affect the operation of computers. A proper amount of airflow round the human body is essential for thermal comfort. The required level of airflow depends on the air temperature and humidity.


Common Indoor Air Pollutants


A wide array of air pollutants can be introduced into hotel environments from diverse sources. Control of air pollutants has been of increased importance to hotel environments because of their perceived effects to building occupants.

The most common hotel pollutants and their sources are listed below:


Asbestos can be present in buildings and building installations in the form of asbestos spray, asbestos-textured paints, flexible joints in air handling units, insulation boards in electrical switch boxes, and brake linings in lift brake drums. Inhalation of asbestos fibres has been linked to asbestosis, lung cancer and mesothelioma (a cancer of the lining of the chest or abdominal cavity).


Biological contaminants include bacteria, fungi and microscopic allergens such as dust mites. Their growth may be accelerated by inadequate ventilation, dirty air filter or ventilation systems, inadequate maintenance and inadequate humidity control. They may cause sneezing, coughing, shortness of breath, dizziness and lethargy. Some of them may trigger allergic or asthmatic reactions.


(Photo 4.3) Elevated levels of nitrogen dioxide and carbon monoxide in the vehicle compartment can affect the health of the drivers and passengers seriously.

Carbon dioxide - a high level of carbon dioxide indoor means there is an inadequate supply of fresh air. This is usually caused by improper partitioning and overcrowding, infrequent window opening, and improper maintenance or operation of the ventilation system. It will make you feel sleepy, and provide a warning for possible build-up of other indoor air pollutants.


Carbon monoxide and nitrogen dioxide can be present in car exhaust, smoke, gas stoves, heaters and fireplaces. Elevated levels of nitrogen dioxide are highly irritating, and elevated levels of carbon monoxide can be fatal.


Tobacco smoke is a mixture of the smoke given off by the burning end of a cigarette or cigar, and the smoke exhaled by the smoker. It is a complex mixture of over 4,000 chemical compounds. It causes Chronic bronchitis symptoms (cough, phlegm, and wheeze), heart attacks, acute stroke and may significantly increase the risk of lung cancer and other respiratory illnesses.


(Photo 4.4) Formaldehyde emissions indoors mainly come from furniture and carpets. (Photo 4.5) Ozone can be produced by laser printers.

Formaldehyde emissions indoors mainly come from furniture, urea-formaldehyde foam insulation, cleaning fluids, adhesives, carpets, etc. Unusually high concentrations of formaldehyde are known to cause eye, nose and respiratory irritation and sensitisation. Formaldehyde is a suspected human carcinogen.


Lead is present in lead-based paint and can become airborne during renovations or when paint flakes off walls.

Outdoor pollution is generated by pollen, dust, car exhaust, combustion by-products and industrial air pollutants, and can be drawn inside buildings through HVAC systems.


Ozone can be produced by equipment that utilises ultra-violet light or causes ionisation of air. This includes photocopiers, laser printers and ionisers. Ozone is highly reactive and can cause serious damage to the lung if inhaled in high concentrations. It also irritates the eyes and respiratory tract. Because it is so reactive, it is only found in substantial concentrations near the source and generally does not tend to accumulate in the indoor environment.


Radon is a colourless and odourless radioactive gas that comes out from concrete building materials containing granite. It can accumulate to a high concentration if the premises are poorly ventilated. Exposure to elevated radon and its decay products may increase the incidence of lung cancer.


Volatile Organic Compounds (VOCs) are emitted from building materials, cleaning agents, cosmetics, waxes, carpets, furnishings, laser printers, photocopiers, adhesives and paints used indoors. Exposure to VOCs at high levels in the industrial environment has been shown to have toxicological effects on the central nervous system, liver, kidney and blood of the human body. Chronic exposure to low doses can also cause reactions. Symptoms such as eye and throat irritation, respiratory problems and headaches can be commonly found. Exposure to compounds such as benzene, a known carcinogen, for long periods may increase the risk of cancer.

(Photo 4.6) Radon is a colourless and odourless radioactive gas that comes out from marble. (Photo 4.7) Volatile Organic Compounds (VOCs) are usually emitted from paints.

 

Controlling Indoor Air Quality in Hotels


There are three basic strategies for controlling indoor air quality :


• The most efficient method is source control - the prevention, reduction and removal of potential pollutants before they are introduced in a closed environment.


• The second method for improving IAQ is ventilation - good design, operation and maintenance of the ventilation system and equipment are essential to the indoor air quality of a building.


• The third method of controlling IAQ is air cleaning (using air filtration equipment).


Indoor air quality is the result of the interplay of many different and often very complex factors as well as unique to each building. It is not a subject, which is susceptible to prescriptive policies. Actions, which may improve air quality in one building might not work in another. In order to prevent and deal with IAQ problems, it is necessary to adopt a specific management strategy to the building. An efficient IAQ Management Programme will reduce costs of cleaning air diffusers, improve lifetimes of materials and reduce potential complaints against the hotel. In the following sessions, some tips for improving indoor air quality, grouped by areas of applications, are described.

 

(Photo 4.8) Carry out indoor air quality testing and monitoring regularly. (Photo 4.9) (Left) Double filters can be installed.
(Right) Multi stages air filtration system including foam mesh pre-filter, electrostatic collecting cell and activated carbon filter can remove airborne contaminants as small as 0.01 micro and remove unpleasant odour.

 

a. Engineering and Maintenance


• Carry out indoor air quality testing and monitoring regularly.


• Eliminate stagnant water accumulation, report water leaks immediately and remove micro-organisms and particulate matter in cooling towers and air-conditioning supply ducts, filters and cooling coils regularly.


• Ensure sufficient fresh air within the building.


• Carry out routine maintenance/cleaning of the ventilation system.


• Schedule the renovation work to periods of low occupancy.


• Ensure the fresh air inlets are located far away from any pollutant sources (e.g. car parks, rubbish shoots, kitchens and washrooms) and avoid blocking the inlets with clutter.


• Do not block air vents or ducts to avoid unbalancing the HVAC system or affecting the ventilation of a neighbouring office. Notify building management if your space is too hot, too cold, stuffy or draughty.


• Properly isolate the area to be renovated from other spaces and the HVAC systems, and schedule these activities for evenings and weekends if possible, to control the odours from paint fumes, welding fumes and renovation.


• Use a high efficiency air filtration method to prevent fungal spores and particulates from entering the air handling units of the ventilation system. Replace the filters at regular intervals.


• Use water-based paints.


• Educate building staff about indoor air quality management by providing training opportunities.


• Establish clear procedures for responding to indoor air-related complaints.


• Inspect and change the air filters of the air-conditioning system more frequently than usual to allow for higher dust load where renovation works take place.


• Arrange dedicated local exhaust with suitable control devices in work areas to reduce dust and other contaminants.


• Clean up the renovated areas and supply large amounts of fresh air to purge them for a period of time prior to occupation.


• Maintain a higher rate of ventilation during the first few months of occupation to help reduce pollutant levels in renovated premises.

 

b. Guest Rooms and Other Guest Facilities

• Use renovation materials, furniture, wallpaper, carpet or wood with low volatile organic compounds, formaldehyde free adhesives and products with green labels as far as possible.


• Old furniture and furnishings, especially those constructed of solid wood, usually emit relatively little formaldehyde. You may consider not replacing them with new ones unless absolutely necessary.


• New furniture items should preferably be aired out for at least several days or weeks before they are admitted indoors. You may consider asking your furniture supplier or distributor to have them aired prior to delivery to your premises.


• For rooms occupied by smokers, use specially designed bedside or coffee tables, which incorporate air cleaners to freshen up rooms and combat smoke and other odours.


• Where possible, toilets and bathrooms with significant sources of sanitary related emission should be maintained under slightly negative pressure, to minimise migration of the pollutants to nearby occupants, which could result in cross-contamination.


• Smoking areas should have air particulate absorbents installed in the air conditioning system to remove particulates in such areas.


• Put a few drops of a special type of tree oil into the ventilation system to minimise the formation of moulds in the cooling coils as tree oil's natural solvent properties make it an excellent biodegradable cleaning product and disinfectant.

 
(Photo 4.10) (Above) Adopt electrostatic air purifier to reduce the amount of suspended particulate in the air and remove the unpleasant odour.
(Below) Adopt nano-photocatalytic oxidation technology to destroy and decompose bacteria, virus, volatile organic compounds and remove offensive odour.

 

c. Housekeeping and Laundry


• Work with the property manager to ensure use of only necessary and appropriate pest control practices, and non-chemical methods where possible.


• Schedule pest control work to hours that affect the least people.


• Conduct daily vacuuming of carpets.


• Dispose of garbage in appropriate containers that are emptied daily to prevent odours and biological contamination.


• Make sure supply air vents and return air ducts are not blocked by furniture or equipment.


• Remove and discard contaminated materials such as mouldy ceiling tiles and carpets as soon as possible. If possible, wash all surfaces that have been contaminated by fungi with dilute bleach.


• Spray humidifiers in the ventilation system can easily become contaminated with bacteria and fungi. A vigorous preventive maintenance programme should be employed with the humidifiers drained and disinfected and any rust or scale deposits removed frequently.


• Do not use perchloroethylene from the laundry (dry cleaning) to clean floors or basin rims.


• Use a cleaning agent with a lower but adequate chemical strength.


• Purchase a non-vented type dry-cleaning machine with a vapour recovery system.


• When it comes to replacing dry cleaning equipment, consider some of the newer technologies such as “wet” cleaning i.e.non-aerosol water based fabric protectants.


• Use alternatives to ozone depleting substance such as R-134a.


• Use non-aerosol packaging such as pump dispensers, which are just as effective as aerosols for spray cans containing spot-cleaning liquids, bathroom and other surface cleaners, paints, pest and other plant sprays (See Chapter 3).


• In laundries, air pressure must be slightly negative.

 

 

(Photo 4.11) Spray a few drops of a special type of tree oil into the ventilation system to minimise the formation of moulds. (Photo 4.12) A dry cleaning machine with a vapour recovery system can control harmful emissions. (Photo 4.13) Put photocopier in an enclosed environment to keep away from densely occupied office space.

 

d. Restaurant and Kitchen


• Eliminate all aerosol products from the kitchen (including cleaners and no-stick cooking sprays).


• Control oil emissions from kitchens using suitable control devices (e.g. electrostatic precipitators).


• Promote a no-smoking policy in the places under your control, and if really necessary, work with the engineering department to design smoking rooms with independent exhaust, which do not allow smoke to circulate through the central ventilation system or to adjoining spaces.


• Where possible, kitchens and canteens with cooking related exhausts should be maintained under slightly negative pressure, to minimise migration of the pollutants to nearby occupants, which could result in cross-contamination.

 

e. Administration


• Provide adequate or separate ventilation for pollutant-generating office equipment such as copiers, printers and fax machines.


• Heavy-duty photocopying should be enclosed in areas away from densely occupied office space to reduce the impact of dust and ozone on the occupants.


• Place computers and heat-generating equipment away from HVAC sensors to avoid inaccurate temperature control.


• Choose man-made or treated materials, such as plywood panels, particle boards, carpets, paints, varnishes and adhesives with very low emissions of formaldehyde and volatile organic compounds (VOCs).

 

f. Vehicle Fleet


• For new vehicles, air out the interiors to minimise VOC emissions from new fittings by opening the doors/windows of the vehicles wherever practicable.


• Keep your vehicles well tuned.


• Avoid using chemical based air fresheners as far as possible, and if really needed, observe manufacturers’ guidelines and recommendations.


• Avoid using chemical agents with volatile organic compounds for cleaning of the fittings, panels, carpet, windows, and flooring of the interior.


• Adequately ventilate the vehicle interiors by opening the doors/windows of the vehicles after the application of pesticides.


• Remove and discard mouldy carpets. If possible, wipe the surfaces with diluted bleach solvent.

• Switch off engines while waiting to help minimise permeation of exhaust gas into the interior. This will also avoid polluting the outdoor environment.

The following table 4.1 lists the minimum levels of ventilation recommended by ASHRAE (the American Society of Heating, Refrigerating and Air-conditioning Engineers) to ensure good indoor air quality.

 

Table 4.1 Recommended Ventilation Levels    
Application Occupancy
(person/1000 ft2)		 Ventilation level
(*cfm/person) (*cfm/ft2)
Hotels, motels, resorts and dorms
Bedrooms, living rooms
30/room
Lobbies
30
15
Conference rooms
50
20
Assembly rooms
120
15
Food and Beverage Service
Dining Rooms
70
20
Cafeteria
100
20
Bars, cocktail lounges
100
30
Kitchen
20
15
Offices
Office space
7
20
Reception areas
60
15
Conference rooms
50
20
Public spaces
Smoking lounges
70
60
Elevators
Variable
1.00/ft2
Sports and Amusement
Spectator areas
150
15
Game rooms
70
25
Ballrooms and discos
100
25

Note: * cfm stands for cubic feet per minute

(Source : American Society of Heating, Refrigerating and Air-conditioning Engineers)

 

Case Studies

a. Case Study 4.1 – A Hotel in Sydney, Australia


A hotel in Sydney, Australia used environmental friendly flooring materials:

• Carpet laid conventionally with grippers and tacks to minimise the release of volatile organic compounds.

• Ceramic tiles (including reconstituted terrazzo) rather than synthetic tiles, since synthetic tiles may emit more volatile organic compounds and cannot be recycled while the environmental impact of producing ceramic tiles is low.

• Timber including recycled timber for the bar areas and stairs.

(Source : Green Hotelier, issue No. 19 July 2000)


b. Case Study 4.2 – A Hotel in Newport Beach, U.S.A.


A hotel in Newport Beach, U.S.A had its water boilers retrofitted to reduce contaminant emissions, and plans to install containment units in the chillers to prevent the discharge of refrigerant from the purge system. In line with the hotel’s concern to preserve air quality, ‘bio-incubators’ have been installed in grease traps and wet wells. These easy-to-install devices allow control and confinement of bacteria growth by accelerating biodegradation.

(Source: Environmental Management For Hotels by International Hotels Environment Initiative)