ASHRAE Journal - August 2024 - 23

COLUMN EQ APPL CATI
COLUMN IEQ APPLIICATIONS
EQ APPLICATIONS
Types of Biomarkers
1. Vital Signs. Heart rate, blood pressure, respiratory
rate and body temperature can indicate physiological
stress due to indoor pollutants. These are noninvasive
and easily measurable but can be infl uenced by
individual differences and external factors; an elevated
heart rate or increased respiratory rate might signal
exposure to high levels of indoor pollutants, such as
volatile organic compounds (VOCs) or particulate
matter. Regular monitoring of vital signs through
wearable devices can provide real-time insights into the
health effects of IEQ.
2. Respiratory. Examples include exhaled nitric
oxide and lung function tests, which directly measure
the impact of inhaled pollutants. These methods are
noninvasive but may vary due to conditions like asthma
or smoking. The emerging fi eld of " breathomics, " which
analyzes the chemical composition of exhaled breath,
holds promise for detecting a wide range of pollutants
and their health impacts. Breath analysis could become
a routine part of IEQ assessments, providing immediate
IAQ feedback.
3. Blood. These include infl ammatory markers,
oxidative stress markers and HbA1c, used in diabetes
management. Blood tests provide systemic indicators
of long-term exposure but are invasive and can be
infl uenced by other health conditions. Blood biomarker
analysis can reveal the cumulative effects of prolonged
exposure to indoor pollutants, such as heavy metals
or endocrine disruptors. For instance, elevated levels
of C-reactive protein (CRP) could indicate chronic
infl ammation due to poor air quality.
4. Urinary. Measuring metabolites of VOCs and
heavy metals in urine is noninvasive and refl ects
recent exposure, though timing and interpretation
can be challenging. Urinary biomarkers can provide a
snapshot of short-term exposures, making them useful
for identifying indoor pollution sources and assessing
mitigation strategies' effectiveness; detecting benzene
metabolites in urine can indicate exposure to tobacco
smoke or off-gassing from building materials.
5. Salivary. Indicators like cortisol levels can be
measured noninvasively, but may be infl uenced by food
intake, drug use and oral health. Salivary biomarkers
offer a convenient, stress-free way to monitor stressrelated
environmental responses. Elevated cortisol
levels, for instance, could refl ect increased stress due to
poor IAQ or noise pollution.
6. Genomic and Proteomic. These high-specifi city and
sensitivity markers are still largely in the research phase,
requiring complex analysis and high costs. Advances in
genomics and proteomics (the study of dynamic protein
products and their interactions) may eventually allow
for identifi cation of specifi c gene expression changes
or protein profi les associated with exposure to indoor
pollutants. This could lead to personalized approaches
to improving IEQ, tailored to an individual's genetic
susceptibility to certain environmental hazards.
Linking Biomarkers to Exposure Pathways
Understanding exposure pathways-how pollutants
enter the body via inhalation, ingestion, dermal
absorption or systemic absorption-is crucial for
selecting appropriate biomarkers; formaldehyde
from medium-density fi berboard (MDF) off-gassing
is inhaled but may cause renal toxicity, suggesting the
need for blood or urine tests rather than lung markers.
Identifying the correct biomarkers for each exposure
pathway ensures accurate assessment of health risks
associated with different indoor pollutants.
Effective IEQ assessment requires a comprehensive
approach that considers multiple exposure pathways
and their interactions. By mapping out these pathways,
researchers can better understand the full impact of
indoor environments on health and develop targeted
interventions to reduce exposure.
Acute vs. Chronic Exposure
Short-term exposure to high levels of pollutants can
result in immediate health effects such as headaches,
dizziness, throat irritation and exacerbation of asthma.
Acute exposure biomarkers include respiratory tests and
rapid vital signs changes; an increase in nitric acid levels
can indicate airway infl ammation due to acute exposure
to pollutants. Acute exposure assessments are essential
for responding to IAQ incidents and implementing
emergency measures to protect occupants.
Long-term exposure leads to persistent health issues
like chronic respiratory conditions, cardiovascular
diseases and cognitive impairment. Chronic exposure
biomarkers include blood samples for infl ammatory
markers and urine tests for long-term VOC exposure.
Cognitive tests, mood and concentration assessments
can assess behavioral changes. Chronic exposure
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ASHRAE Journal - August 2024

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