Environmental Engineering Reference
In-Depth Information
After the on-site inspection, occupant interview, and air testing/envi-
ronmental sampling, the investigator should evaluate all information
obtained during the investigation. During this evaluation process, he/she
should determine whether symptoms/health problems/complaints are con-
sistent with observations made during the inspection, as well as with results
of air/environmental sampling.
2.
Diagnosing specific residential indoor environment problems
Though the nature of residential IAQ/IE complaints varies, only a relatively
few contaminants are responsible. These include biological contaminants
such as mold and allergens produced by dust mites, pets, and insects;
HCHO; CO; pesticides; lead dusts; sewer gases; and, increasingly, soot pro-
duced by candle burning. Complaints may include significant health effects
or be of a nuisance nature. Diagnostic criteria used to evaluate residential
indoor environment problems are summarized below.
Biological contaminants, as indicated in
Chapters 5 and 6, are the major cause of allergy, asthma, and recurring
sinusitis in tens of millions of North Americans annually. These ailments
have characteristic symptoms and clinical findings that can be used to
identify potential causal agents. Individuals affected often have a family
history of allergy or asthma and test positive to specific allergens in standard
allergy testing.
Building diagnoses associated with allergens is best conducted in con-
sultation with a physician trained in allergy or immunology. When such
consultation is impractical, the investigator should use professional judg-
ment in evaluating the potential cause of allergy/asthma/sinusitis among
occupants of a residence.
Risk factors that can be used to evaluate biological contaminants as
potential causes of allergy/asthma/sinusitis associated with residential
a.
Biological contaminants.
Fortunately, HCHO is less likely to cause IAQ-
related health complaints today than at any time in the past three decades.
Because of changes in the use of construction materials and improvements
in products bonded with urea-formaldehyde resins, indoor HCHO concen-
trations (even in many new dwellings) are relatively low and are unlikely
to cause health problems. Despite this, HCHO may cause symptoms in
sensitive individuals in environments such as new mobile homes constructed
with urea-formaldehyde-bonded wood products and homes with new wood
cabinetry or furniture. Factors that suggest HCHO exposures may be respon-
sible for reported health complaints include: (1) symptoms characterized by
eye and upper respiratory system irritation, headache, and fatigue; (2) symp-
toms more severe on warm, humid days; (3) potent HCHO-emitting sources
present; and (4) HCHO levels determined under near-optimum testing con-
ditions (closure, humidity >50%, temperature 22 to 25°C, moderate outdoor
conditions)
b.
Formaldehyde.
≥
0.05 ppmv.
