Home > News > Quality Air
Quality Air
25 August 2004 | Link | Director John Herbert
A Real Problem
The air pollution levels over the last week have soared, with the Air Pollution
Index (API) breaching the 100 danger level, and the obligatory finger pointing
commences.
However, not wishing to bore you with the benefits of free and cheap renewable
energy, this article is focusing a bit closer to home, in fact you are
probably sitting their right now - your workplace.
Contrary to media reports, the EPD reported on 19th August 2004, that the
primary reason for the reduced visibility was abundant RSP in the atmosphere.
RSP for the uninitiated, is an acronym for Respirable Suspended Particles. As the
name implies these particles are of a size that can be inhaled deep into the
lung. It takes no special effort to inhale RSP, if they are in the air, they
are filling your lungs as you read. Typically, any particle between 1-10
microns is classified as RSP.
You may also read banter reading quoting PM2, PM5, or
PM10 - refer to the physical size of the particulates, PM2 has size of 2 microns.
Presently EPD measure total RSP, and don't differentiate according to size.
RSP's are primarily created during the combustion process, the product of
combustion include RSP, primarily due to incomplete combustion of diesel fuel.
Other contaminants, including the less well know particles such as atomised
water droplets containing Legionella would fall into this category too. However,
here in Hong Kong most of the RSP's that are blocking the harbour view where
created during the combustion process.
Cause for Concern
RSP are particularly concerning because they directly, and in some cases
terminally, affect your health.
It is widely documented, but rarely publicised, that breathing air contaminated
with RSP directly causes increases hospital attendance, respiratory and a
major causative factor for life threatening illnesses. Studies by The University
of Hong Kong amongst others, provide a direct correlation between increasing
morbidity and poor air quality. Certain professions are more at risk than others, but
we don't generally spend that much time outdoors in the summer so what is the problem?
It is not widely reported, that when the outdoor air is unhealthy, the indoor
environment including your workplace is equally so. The same RSP that are causing
ships to collide in the harbour are also reticulating in your workplace.
Rushing into your office or workplace, whilst certainly cooler, it is not a
sanctuary, often we find the indoor RSP concentration is double that of outside,
and exceeds WHO objectives - indoors we just can't see the pollutants with the
naked eye.
There are a number of chemicals that may constitute part of RSP. Two
particularly important constituents are lead and aromatic hydrocarbons.
Constituents of RSP may include; Silicon, Aluminium, Calcium, Manganese and Iron,
Vanadium, Nickel, Cadmium, Carbon, Lead, Bromine, hydrocarbons, Sodium, Chloride,
magnesium, and Potassium Nitrate, Sulphate or Ammonium in varying concentrations
depending on the source. To view a typical analysis from EPD
click here
Filtrate
In almost every commercial office building and shopping mall in Hong Kong,
outdoor air is drawn into air-conditioning equipment, mixed with room air,
cooled and circulated in the occupied space. Generally the reticulated and mixed
air is not filtered.
Although the outdoor air is 'filtered', one should take a closer look at the
unit. Over the last twelve years I have looked at thousands, the typical
commercial building filter efficiency for RSP is pretty much close to zero.
Therefore, outdoor air complete with RSP are drawn into our air-conditioning
systems and subsequently distributed throughout the building.
Certainly, some RSP are trapped due to impingement (sticking to other trapped
particles in the filter) however because of their minute size, RSP circumvent
standard filters.
Evidence
Is there evidence to support the theory? You might be surprised to learn that
the Hong Kong government indoor air quality survey provides an
independent source for reference.
The government funded independent study found that more than 30% of buildings
investigated suffered from poor indoor air quality. And managers wonder why
employee's are absent so frequently?
However, if we further consider the buildings surveyed a different picture
emerges. Most buildings included in the survey were government owned buildings,
Grade A commercial buildings, and other quality buildings, where one would
expect an exemplary and pro-active maintenance activities.
However, most buildings in Hong Kong fail to meet that criteria, and are
generally of a lesser standard, without maintenance crews. Therefore, it is
reasonable to believe the that the reported thirty percent (30%) is the low end
of a range that in reality extends to well above fifty percent (50%).
These would include premises using the ubiquitous window type units
air-conditioning units, since these units have no outdoor air filtration
whatsoever.
The government has estimated the cost of poor indoor air quality at
about three billion Hong Kong dollars) per year, undoubtedly the real
cost is higher.
Solutions
Considering that a typical working day equates with two hour outdoor exposure
and eight hour plus workplace exposure, it is clear that workplace improvements
will have a significant impact on your health.
Presently, under the current Building Regulations Ordinance Cap. 123 (Fire)
combustible materials are prohibited.
Therefore solutions need to satisfy both regulatory and function needs, namely
non-combustible, significantly reduce contaminants including RSP, and ideally
low maintenance.
Author
Mr John Herbert is the Director at Kelcroft E&M Limited.
Educated and trained in the United Kingdom, he has managed and engineered solutions
for more than twenty years, advised clients across three continents, whilst retaining
a litigation free record.