- The One-Page Snapshot: Exam Format at a Glance
- The Six Official Domains, Decoded
- The Seven Assigned Publications
- Eligibility Routes and Application Mechanics
- Fees, Validity, and Recertification
- Reading the Published Numbers Without Overreading Them
- Accreditation: What to Verify Before You Claim It
- Sequencing Your Review by Domain
- Frequently Asked Questions
- The CEAI exam is 100 closed-book multiple-choice questions in 3 hours, with a 75% passing score.
- Six official domains cover allergic response through guidelines, regulations, and standards; ACAC publishes no domain weights.
- Seven assigned publications, from the EPA, CDC, HUD, HHS, APHL, and Levetin, define the reading list.
- Fee and recertification details conflict across ACAC sources, so confirm current figures before budgeting.
The One-Page Snapshot: Exam Format at a Glance
The Council-certified Environmental Allergen Investigator credential is issued by the American Council for Accredited Certification (ACAC). This cheat sheet condenses the facts that matter most in the final stretch of preparation. If you are brand new to the credential, start with What Is CEAI Certification? and come back here when you want a fast review.
| Item | CEAI Fact |
|---|---|
| Certifying body | American Council for Accredited Certification (ACAC) |
| Testing provider | Kryterion, Inc. |
| Questions | 100 multiple-choice, each with at least four answer options |
| Time limit | 3 hours |
| Reference materials | Closed book |
| Passing score | 75%, set using the Modified Angoff Method |
| Delivery | Computer-delivered at a test center or via secure online video proctoring |
| Results | Scores are immediate, with email confirmation |
| Validity | Two years |
Two format details deserve attention. First, the Modified Angoff Method means the cut score reflects expert judgment about what a minimally competent investigator should know, not a curve against other candidates. Second, because the exam is closed book, you cannot look up sampling protocols or regulatory language mid-exam; you must carry them in memory. For a deeper look at how the cut score works, see CEAI Passing Score 2026.
The Six Official Domains, Decoded
The six domain headings below reproduce the official public CEAI examination headings. ACAC's reviewed sources do not publish percentage weights for any domain, so treat every domain as testable and avoid any study plan that claims to know which area counts most. A fuller breakdown lives in CEAI Exam Domains 2026: Complete Guide to All 6 Content Areas.
Domain 1: The allergic response in humans
This domain frames why investigations matter. Expect questions on how exposure to an allergen leads to symptoms and how that connects to health outcomes such as asthma.
- Know the vocabulary of sensitization, exposure, and symptom triggers well enough to recognize it in scenario questions.
- Connect allergen exposure to asthma, which is the focus of the HUD Healthy Homes asthma publication on the reading list.
- Be ready to separate an allergic response from irritant or non-allergic reactions in a described case.
Domain 2: Types of allergens and their presence in the built environment
Here the exam asks what the allergens are and where they live inside buildings.
- Review the major indoor allergen categories covered in the HHS airborne allergens booklet and the CDC Healthy Housing Reference Manual.
- Understand where allergens accumulate: dust reservoirs, bedding, soft furnishings, and moisture-affected materials.
- Know the difference between allergens that become airborne and those that settle in dust, since that distinction drives sampling choices.
Domain 3: Principles of the Built Environment
This is the building-science domain. Investigators must understand how structures, moisture, and airflow influence allergen presence.
- Study how building envelope, ventilation, and moisture behavior create conditions for allergen growth and distribution.
- Connect building features to the housing-and-health framing in CDC Healthy Housing chapter 5.
- Candidates with architecture, engineering, or industrial hygiene backgrounds often find this domain familiar; microbiology-trained candidates should invest extra time here.
Domain 4: Investigation principles, procedures, and equipment
Likely the most hands-on domain, and the one tied most closely to the specialized assigned readings.
- Master aeroallergen sampling approaches from the Levetin review, Methods for Aeroallergen Sampling.
- Learn the HUD vacuum dust sample collection protocol for allergens, including how and why dust samples are gathered the way they are.
- Understand the role of environmental laboratories and indoor air testing from the APHL primer, including what labs can and cannot tell an investigator.
- Know how to design an investigation, since the eligibility rules emphasize experience designing and conducting them.
Domain 5: Allergen evaluation and remediation strategies
Once data is collected, how do you interpret it and what do you recommend?
- Practice moving from sampling results to a defensible conclusion without overstating what the data show.
- Review remediation strategies at the level of principles: source control, cleaning, moisture correction, and verifying outcomes.
- Use the EPA Exposure Factors Handbook, chapter 19, as grounding for how exposure is characterized when evaluating risk.
Domain 6: Guidelines, regulations, and standards
The exam closes with the framework investigators work within.
- Expect questions drawing on the federal agency publications on the reading list, including EPA, CDC, HHS, and HUD material.
- Be precise about the difference between a guideline, a regulation, and a standard, since distractor answers often blur them.
- Because the exam is closed book, memorize the key protocol names and the agencies behind them.
The Seven Assigned Publications
ACAC's shared study packet names seven publications. The publication years below are the dates of the references themselves, not exam-release dates, so a 2003 booklet is not "outdated exam content" simply because of its age. ACAC recommends reading the complete assigned texts rather than only highlighted review pages, and that advice is worth taking seriously because the exam draws on full-document context.
| Publication | Most relevant domains |
|---|---|
| APHL, Environmental Laboratories and Indoor Air Testing: A Primer (2015) | Domain 4, Domain 5 |
| CDC, Healthy Housing Reference Manual, chapter 5 (2006) | Domain 2, Domain 3 |
| EPA, Exposure Factors Handbook, chapter 19 (updated 2018) | Domain 5, Domain 6 |
| Levetin, Methods for Aeroallergen Sampling, Current Allergy and Asthma Reports 4:376-383 (2004) | Domain 4 |
| HHS, Airborne Allergens: Something in the Air (2003) | Domain 1, Domain 2 |
| HUD, Healthy Homes Issues: Asthma (2012) | Domain 1, Domain 6 |
| HUD, Vacuum Dust Sample Collection Protocol for Allergens (2008) | Domain 4 |
The domain mapping above is a study aid, not an official crosswalk; ACAC does not publish which publication feeds which domain. Use it to organize your notes, and expect overlap. For a full preparation plan built around these materials, see the CEAI Study Guide 2026.
Eligibility Routes and Application Mechanics
Eligibility is experience-driven. ACAC describes two routes, and both require applicants to show they have designed and conducted environmental allergen investigations.
Route one: education plus one year
- A qualifying two-year degree, or ACAC's stated equivalent of 15 credit hours, plus at least one year of documented environmental allergen investigation experience.
- Qualifying education includes microbiology, engineering, science, architecture, industrial hygiene, or a related science.
- Applicants claiming education credit submit transcripts and four project sheets.
Route two: no degree plus two years
- No degree, but at least two years of consulting experience in environmental allergen investigations.
- A high-school diploma or GED is required.
Either way, you complete the online application and the required email verifications. There is no mandatory training course. Experience verification, passing the examination, and unanimous board approval are separate certification requirements, so passing the exam alone does not award the credential. For the full eligibility walkthrough, read CEAI Requirements 2026.
Fees, Validity, and Recertification
What ACAC lists
ACAC's Fees and Payments page lists a USD 100 examination component that is separate from certification charges, and a USD 100 retake. Its general accredited-certification schedule shows USD 500 initially, made up of USD 400 for certification plus USD 100 for the examination, and USD 400 per two-year renewal.
These are published category rates, not a separately verified CEAI-specific quotation. The credential-specific application page did not render during our review, and accreditation wording across ACAC pages conflicts. Confirm the applicable total with ACAC before you budget rather than assuming the category rate applies. For a full cost discussion, see CEAI Certification Cost 2026.
Validity and recertification
- The certification is valid for two years.
- Current recertification procedures require 40 recertification credits (RCs) per term: 10 for continued field activity plus 30 hours of professional development.
- Keep records, since they may be audited.
Exam-day arrival
The handbook says to arrive 30 minutes early for a test-center appointment, while the general examination page says 15 minutes. Follow the instructions in your appointment confirmation, and when in doubt, take the earlier time. Exam scheduling logistics are covered in CEAI Exam Dates 2026.
Reading the Published Numbers Without Overreading Them
ACAC's Accredited Certification Activity summary, current as of December 31, 2025, reports a CEAI examination pass ratio of 50%, two applicants in 2025, and one current certification at that date.
Treat that figure with caution. With only two applicants, a single result swings the ratio dramatically. Applicant totals can also include licensing-only candidates. The 50% is not a verified first-attempt rate, not a long-run rate, and not a prediction for 2026. The honest reading is that the sample is too small to say much about difficulty. Our discussion in CEAI Pass Rate 2026: What the Data Shows goes further, and How Hard Is the CEAI Exam? looks at difficulty from the content side instead.
Key Takeaway
Do not let a two-applicant statistic make you complacent or anxious. Prepare to the 75% standard across all six domains, because the weights are unpublished and any domain can carry real points.
Accreditation: What to Verify Before You Claim It
ACAC's Environmental Allergen Consulting page describes the CEAI and CEAC as CESB accreditation applicants, and the 2025 accredited-activity report includes both. However, the public CESB Members list does not list CEAI or CEAC. Absence from a list does not by itself settle status, so current accreditation remains unverified.
The practical rule: do not state in a résumé, proposal, or marketing material that the CEAI is CESB-accredited unless ACAC or CESB confirms it to you directly. Employers weighing the credential should ask the same question. For career context, see CEAI Jobs and Is the CEAI Certification Worth It?. Salary context is in the CEAI Salary Guide 2026, though no earnings figure should be assumed from this cheat sheet.
Sequencing Your Review by Domain
One short note on method: because the exam is closed book and the weights are unpublished, sequence your review by dependency rather than by guesswork. Start with the foundations the later domains build on, and save the most procedural, memorization-heavy material for a stretch close to exam day.
Health and allergen foundations (Domains 1 and 2)
- Read the HHS airborne allergens booklet and the HUD asthma publication in full.
- Build a one-page list of allergen types and where they occur in buildings.
Building science (Domain 3)
- Work through CDC Healthy Housing chapter 5.
- Link moisture and ventilation conditions to allergen presence.
Investigation methods (Domain 4)
- Study the Levetin sampling review, the HUD vacuum dust protocol, and the APHL laboratory primer.
- Memorize protocol steps and equipment purposes.
Evaluation, remediation, and rules (Domains 5 and 6)
- Read EPA Exposure Factors Handbook chapter 19.
- Drill the guideline-versus-regulation-versus-standard distinction, then take full-length timed practice sets.
When you are ready to test recall under realistic conditions, use the CEAI practice tests to simulate the 100-question, 3-hour format, and review misses against the matching assigned publication rather than against a summary. You can also revisit the main practice test site to track which domains need another pass.
Frequently Asked Questions
The exam has 100 computer-delivered, closed-book multiple-choice questions, each with at least four answer options, and you have 3 hours. A passing score is 75%.
No. ACAC's reviewed sources list the six domain headings but do not publish percentage weights, so you should prepare for all six rather than assuming some count more.
Yes. Both test-center delivery and secure online video-proctored delivery are available through Kryterion, Inc., and scores are immediate with email confirmation.
No mandatory training course is required. You do need documented investigation experience, the exam, and unanimous board approval, which are separate requirements. See CEAI Training for optional preparation resources.
No. They are separate ACAC credentials that share a study packet. The CEAC has a 120-question exam and higher experience requirements, and neither should be applied to the CEAI.