ASHRAE Journal - July 2024 - 45

TECHNICAL FEATURE
example, in Europe15 it is estimated that infl uenza
causes about 82 DALY per year/100,000 people . In
the U.S., traffi c accidents16 cause about 520 DALY per
year/100,000 people. Smoking17 causes about 3,000
DALY per year/100,000 people). In China18 the burden of
disease from IAQ (smoking or infectious diseases are not
included as part of IAQ here) is estimated to be about the
same level as smoking.
One can set standards based as DALY limits instead of
concentration limits. The World Health Organization
(WHO), for example, has looked at dozens of
contaminants found in drinking water and set a stretch
guideline19 level of 0.1 DALY per year/100,000 people for
the total without setting specifi c limits on any of them.
ASHRAE could do similar things for indoor air, but it
requires knowing what the contaminants of concern are
and how much harm is associated with unit exposure to
each. That is a very daunting task.
Fortunately, the English have again helped with
a paradigm shift-this time without burning any
buildings down; Giobertti Morantes20 at the University
of Nottingham and his coauthors (which includes
yours truly) have just done the daunting task for us.
The authors have made no measurements themselves,
but rather have collected all the epidemiological
and toxicological data on constituents of air as they
could fi nd. They have converted that data to a harm
intensity (HI) for each. Harm intensity is the harm
done per unit dose of a contaminant, and the units are
typically DALY per µg/m3·yr per 100,000 people. (Not all
contaminants are quantifi ed by µg/m3, so for some such
as mold or radon, different units are used.)
Table 1 of that report contains 44 contaminants and is
the key result that enables ASHRAE to move to a harm
paradigm. The harm used by Morantes and generally
in this fi eld is often called personal harm, because it is
what the individual suffers. (See " Monetizing DALYs "
sidebar. )
As shown in Figure 2, Morantes estimated that the
global burden of disease (GBD) was principally due
to particles (PM10), most of which was due to the fi ne
particles (PM2.5), but also includes coarse particles.
Notably absent from this listing is carbon dioxide
(CO2). CO2 is not itself a contaminant of concern, but as
explained in the " ASHRAE Position Document on Indoor
Carbon Dioxide " 21 it does have a role to play and can
be used as a surrogate for occupancy or to determine
FIGURE 2 Fraction of global burden of disease for indoor air quality imputed by
Morantes. 99% is explained by particles, NO2, HCHO, and Rn.
Global Burden of Disease from IAQ (2,200 DALY per yr/100,000 people)
 Fine Particles
 Coarse Particles
 Nitrogen Dioxide
 Formaldehyde
 Radon
 Other
TABLE 1 Estimates of harm for six selected contaminants at design compound
maximum limits allowed by Standard 62.1-2022.
HARM INTENSITY,
DALY
COMPOUND
Acetaldehyde
Benzene
Formaldehyde
Naphthalene
Ozone
PER µg/m3·YR
PER 100,000
PEOPLE
0.053
0.067
4.3
0.36
1.3
HARM,
62.1 LIMIT,
µg/m3
140
3
33
9
137
DALY/YR PER
100,000
PEOPLE
7.42
0.20
141.90
3.24
178.10
PERSONAL HARM
$/YR PERSON
(AMERICAN)
$56
$2
$1,064
$24
$1,336
minimum ventilation rates necessary to deal with
human bioeffl uents.
It is clear, but not really news, that on a global
basis, particles dominate the harm from indoor air
contaminants. Morantes estimates GBD for IAQ to be
2,200 DALY per year/100,000 people. The U.S. valuation
of that would be over $16,000/yr per person, but the
ventilation practices and requirements (e.g., Standard
62 ) that developed countries currently enjoy lower that
number.
ASHRAE Standard 62.1-2022's Indoor Air Quality
Procedure (IAQP) uses a hazard paradigm; we can use
the harm intensity data to see the qualitative and
quantitative differences between the hazard and harm
paradigms. Table 1 takes six of the 15 design compounds
from Standard 62.1 and uses Morantes' harm intensities
to determine how much harm the exposure to
contaminants at these levels would represent.
The biggest contributor is still fi ne particles.
62.1-2022's IAQP does not contain an entry for the
globally most- important chemical compound, nitrogen
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45
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ASHRAE Journal - July 2024

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