10 exam-style questions with answers and explanations, straight from our 1,030-question bank. Tap an answer to check yourself. When you're ready, take the scored version in the free practice test.
The CRIE exam has 50 questions and runs 2 hours.
These 10 free CRIE questions are organized by exam domain, so you can see how each part of the Council-certified Residential Indoor Environmentalist blueprint is tested. Reveal the answer and explanation under each question.
A child's asthma symptoms repeatedly worsen when the home's gas range is used. Monitoring throughout cooking shows carbon monoxide and fine-particle concentrations remain near background. The range hood recirculates air into the kitchen. Which additional pollutant deserves particular attention?
Correct answer: C - Nitrogen dioxide from combustion
An older home's pipe insulation is pale, fibrous, and similar in appearance to asbestos-containing insulation in a reference photograph. Renovation will disturb it. What would establish whether this particular material contains asbestos?
Correct answer: B - Laboratory analysis of a representative bulk sample collected by a qualified asbestos professional
A homeowner needs a timely radon decision and completes an initial short-term test followed by a second short-term test in the same regularly occupied room. Both tests meet the applicable test conditions. Results are 6.8 and 3.0 pCi/L. Under EPA's two-test approach, how should the findings be combined and used?
Correct answer: C - Use the 4.9 pCi/L average to recommend radon reduction.
Formaldehyde-specific sampling finds elevated concentrations after a room is refurnished. Four uncoated wood products are listed in the material inventory. Which should lead the source investigation based on its binder chemistry?
Correct answer: D - Urea-formaldehyde-bonded medium-density fiberboard
The builder of a new slab-on-grade house attributes an elevated radon result to the concrete itself, arguing that a house without a basement cannot admit soil gas. The house uses municipal water. Where should the source investigation concentrate first?
Correct answer: D - Soil gas entering slab joints and pipe openings
Consider two trials of the same ultrasonic humidifier, with the room cleaned between trials and all operating settings unchanged. Tap water produces fine white deposits on nearby surfaces; freshly distilled water produces very little residue. This comparison most strongly implicates:
Correct answer: B - Minerals dispersed from the humidifier water
"The result is below the reference value, so that amount of lead must be harmless." A parent makes this statement about a two-year-old's venous blood lead result of 2.1 micrograms per deciliter. CDC's reference value is 3.5 micrograms per deciliter. What does that reference value actually signify?
Correct answer: B - It identifies higher-than-typical exposure, not a safe-versus-harmful threshold.
A contractor treats a mold-covered wall with a fungicide but leaves the fungal material in place. For a resident with a diagnosed mold allergy, what remains true even if the treatment kills the mold?
Correct answer: C - Nonviable mold material can still provoke an allergic response.
Halfway through a home assessment, two occupants report new headaches and nausea. A gasoline generator is running in the attached garage with its overhead door open. The indoor CO alarm has not sounded. What should the investigator do first?
Correct answer: A - Get everyone outdoors immediately and call emergency services from outside.
Laboratory records confirm asbestos in a home's resilient floor tiles. The tiles are firmly bonded, undamaged, and protected from abrasion; no renovation or other disturbance is planned. Which recommendation fits these conditions?
Correct answer: A - Leave the tiles undisturbed and periodically check their condition.
The CRIE exam also covers these domains. Drill them in the full free practice test:
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