Good air quality

There is a risk of pollution from external sources such as car parking, attached garage, busy road, power plant, industry, cooling towers, landfill site, or agriculture. Potential IAQ problems are infiltration of toxic gases such as benzene, CO, NOx, etc., dust and bad smells.

93% of audited office buildings had nearby external sources of pollution, most of these being busy road (69%), car parking (59%) or attached garage (24%).

No statistically significant differences were observed for BSI and odour in the air between office buildings with and without nearby source of pollution such as car parking, busy road, power plant, etc. The reason maybe either relatively low strength of the external sources, or measures taken to avoid the effect of these sources.

However, in the measurements carried out in the detailed field investigations, the presence of VOCs or dust was shown to be present in several buildings close to pollution sources and in which appropriate measures were not taken.

Avoid outdoor sources:

• Build garage in a separate building.
• Build an airtight wall or deck (no door) between garage and living space.
• Install a ventilated lock or an airtight door and ensure a positive pressure difference between living space and garage.
• In radon area, design radon ingress control with proper construction of foundation (occupied space separated from the ground by a ventilated space) or ventilation (control of pressure difference), or other measures (e.g. mechanical ventilation).
• Buildings with more susceptible occupants that should be protected from outdoor sources (e.g. hospitals, homes for elderly, schools) should not be located in city centres, or at least placed far from busy roads, power plants, industrial area, and landfill sites.

It is possible to reduce the number and the strength of the internal pollution sources by applying the following recommendations:

• Choose materials that do not emit pollutants or that have low source strength. More and more providers and the SOPHIE database (Bluyssen, de Oliveira Fernandes et al. 2000) give information on the emissions of their materials and products.
• Avoid polluting activities indoors, or ventilate strongly and locally the areas where these activities are performed.
• Use cleaning agents and maintenance material such as paints that do not contain toxic solvents or components
• Do not smoke in buildings (prohibited in office buildings in most countries).
• Follow the AIRLESS recommendations (see below) in mechanically ventilated buildings

The EU project AIRLESS proposed several recommendations for improving the indoor air quality and energy performance of mechanical ventilation. These are remembered below, together with HOPE complements.

• Recirculation should be avoided, except in some specific cases like clean rooms
• Use a heat recovery system that is well-installed and in a building that is not leaky
• Use a rotating heat exchanger with purging sector, and only if recirculation of certain odours is not a problem
• Avoid humidification whenever possible, and always avoid too high humidity
• Apply operation strategies focussed on shutting the system down when no air is required
• Use a filtering system that "cleans" the air and has a resistance as low as possible
• Use ductwork that is clean (free of oil residuals and dust), smooth, as large as possible and has as less curves as possible
• If cooling is applied use a cooling coil with a droplet catcher
• Increase/decrease the set point for cooling/heating as much as possible (with respect to comfort conditions of occupants)
• Commissioning the air handling system after installation is essential.