Indoor Air Contaminants

Given enough time nature can restore a site contaminated with organic compounds such as VOCs. One reason for this is that, frequently, materials such as VOCs that are toxic to some life are food for others. Most of the biological breakdown of VOCs is done by beneficial microbes, higher plants are not typically directly involved but facilitate the process . Some pollutant-degrading species are usually present and active in most environments, and the act of introducing the pollutant only increases their relative numbers and/or activity levels. The NEDLAW active wall is a biofilter containing such organisms to remove contaminants present in the air at very low concentrations. In essence, we mimic indoors what happens outdoors every day.

The following are some of our Biofilter wall performance results. We are proud of the science behind our walls. An active biofilter is much more that simply plant material on a vertical surface.

TABLE 1

LABORATORY AND CASE STUDIES ON THE PERFORMANCE OF INDOOR AIR BIOFILTERS

CONTAMINANT

OUTCOME

SOURCE OF DATA

Volatile Organic Compounds (VOCs)

A Space maintained without outside air had air quality as good or better than similar spaces maintained by traditional ventilation.	Darlington et al.2000
Effluent from the biofilter had the same quality as outside air, with up to 70% VOCs removed	Darlington 2005

Formaldehyde

Space maintained with a biofilter had lower formaldehyde concentration than spaces maintained by traditional means

The biofilter lowered concentrations to background levels

Darlington et al. 2000

Odor

Odor panel studies revealed almost complete removal (80% removal)

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Spores

Areas treated by biofilter did not exhibit elevated counts	Mallany 2000
Biofilter Slightly reduced moulds and bacteria counts	Smith 2006 Liddy 2007

Dust

Biofilter reduced inhalable dust concentration No/little impact on respirable dust

Smith 2006
Liddy 2007

Impact of Biofiltration on Indoor Air Quality

Impact of biofiltration on IAQ. The graph presents two lines. The first line indicates concentration of VOCs in a space under a range of ventilation (typical ventilation). The concentrations are presented relative to those seen when the space is subjected to ventilation rates 7.5 litres per person per second. The second line is the relative concentration when the space is subjected to the same range of ventilation but the air in the space is also treated with a standard-sized biofilter (ventilation + biofilter).