Allergens (dust mite, pet, pollen)
There is no regulatory limit for indoor allergens. Engineering, not a diagnosis, lowers your exposure.
Dust mites, pet allergens, and pollen are the everyday triggers behind environmental allergies. About 1 in 3 US adults has diagnosed allergic rhinitis, and far more notice their symptoms around pets or in pollen season. You keep the pet and the carpet and the open windows. Engineering the home around those choices reduces exposure: HEPA filtration, bedroom humidity below 50%, and mattress encasements.
What it is, and where it comes from
Three biological exposures share your home. Dust mites live in mattresses, bedding, carpet, and upholstery, feeding on shed skin; the allergen is their fecal pellets, which accumulate for weeks after the mites themselves are gone. Pet allergens come from cats (Fel d 1, made in sebaceous glands, not mainly saliva) and dogs (Can f 1, dominant in saliva and dander); both stick to walls, fabric, and clothing and persist for months after a pet leaves. Pollen is the seasonal driver, entering through open windows, unfiltered HVAC intake, and tracking in on shoes and clothing. All three concentrate in textile reservoirs and resist source removal, which is why they are an engineering problem rather than a cleaning one.
Why it matters
Two mechanisms run at once. In the roughly 1 in 5 to 1 in 3 adults sensitized to a major indoor allergen, the classical IgE pathway fires: mast cells in the nose, eyes, and airways release histamine, driving congestion, sneezing, conjunctivitis, and asthma flares. Separately, dust-mite enzymes physically damage the airway lining in everyone exposed, sensitized or not, by cleaving the tight-junction proteins that seal the epithelium. The downstream cost shows up clearest in diagnosed allergic rhinitis, where most patients report poor sleep against about a quarter of people without it, because nasal congestion fragments the night. The engineering recommendations apply to everyone exposed, diagnosis or not.
- Childhood exposure above ~10 µg/g of dust-mite allergen tracked with roughly a fivefold higher asthma rate by age 11, and most US bedrooms exceed the ~2 µg/g sensitization mark.Sporik et al., 1990 (N Engl J Med; Der p I exposure and childhood asthma)
- Dropping bedroom humidity below 50% kills dust mites faster than they breed; the desiccation half-life of D. farinae falls from about 86 weeks at 50% RH to about 12 weeks at 45% RH, while populations grow only above that range.Arlian et al., 1999 (J Allergy Clin Immunol; reducing RH to control D. farinae)
- Across 196 so-called hypoallergenic dogs and 160 standard dogs, allergen levels were not lower in the hypoallergenic group; their hair carried more Can f 1. Hypoallergenic is a marketing label, not a measured difference.Vredegoor et al., 2012 (J Allergy Clin Immunol; no evidence any dog breed is hypoallergenic)
- In mite-sensitized children, mite-impermeable bed encasements cut severe asthma flares meaningfully, with about a 45% reduction in emergency visits; in adults, encasements used alone did not show the same clinical benefit, so framing must stay honest.Murray et al., 2017 (Am J Respir Crit Care Med; mite-impermeable bedcovers and childhood asthma exacerbations)
What we grade it against
| Contaminant | Health-based level | Source (health-based) |
|---|---|---|
| Dust-mite allergen, Der p 1 (µg/g dust) | Lower is betterAbove ~2 µg/g raises sensitization risk; above ~10 µg/g tracks with childhood asthma development. No safe floor is defined. | Sporik et al., 1990 (N Engl J Med) |
| Bedroom relative humidity (%) | Below 50%Mites cannot drink and pull water from air; sustained sub-50% RH desiccates them faster than they reproduce. | Arlian et al., 1999 (J Allergy Clin Immunol) |
| Cat allergen, Fel d 1 (µg/g dust) | Continuous dose-responseNo single defensible threshold; a proposed 8 µg/g cutoff was not confirmed in adults. Lower is better. | Heinrich et al., 2015 (PLOS ONE) |
| Indoor pollen (grains/m³) | Season-drivenNo defensible indoor threshold. Outdoor counts are reported by AAAAI National Allergy Bureau stations; the control is closed windows during peak season, not a number. | AAAAI National Allergy Bureau |
Health-based levels come from peer-reviewed research and government risk scientists working without cost constraints. Legal limits are enforceable compromises. Your report grades to the health column.
What helps
Direct fixes
- MERV-13 whole-house HVAC filter
Captures the airborne fraction of mite fecal pellets, pet allergen, and pollen as air circulates; portable-HEPA analogs reduced dog allergen ~89%, cat ~77%, and mite ~75% in controlled trials.
Filtration cleans circulating air only. It does not touch the allergen reservoir settled in the mattress, carpet, and upholstery.
- Bedroom HEPA air purifier (sized via the PM2.5 CADR formula)
Reduces airborne pet allergen and the lung-depositing fraction of pollen and mite allergen; reuses the existing Stasis PM2.5 device, so no incremental hardware.
HEPA handles airborne particles, not the settled mite reservoir; encasements and sub-50% RH address that. Mite-allergen reduction in trials was marginal versus the strong pet-allergen effect.
- Bedroom humidity held below 50% (verified by the 7-day sensor reading)
Desiccates dust mites below their survival range. In dry, AC-reliant climates this often already sits near 40-50% passively; the audit confirms it before recommending a dehumidifier.
RH control is mite-specific. It does nothing for pet allergen or pollen, which need filtration and source-entry control.
Bigger retrofits
- Mattress, pillow, and boxspring encasements (pore under 10 µm)
Seal off the largest mite reservoir, cutting mattress Der p 1 by roughly 80-90%. Clearest benefit in sensitized children and when combined with HEPA, MERV-13, and RH control.
Real exposure reduction, but encasements used alone did not show clinical asthma benefit in the largest adult trial. They are one layer of a combined approach, not a standalone fix.
- Hard-floor conversion where deep carpet is the dominant mite reservoir
Removes the carpet base layer, where mite-allergen concentration runs about five times the surface level. Surfaced only when the questionnaire flags deep-carpet bedrooms with sensitized household members.
An expensive lifestyle change, not a Stasis-delivered fix. Offered as information; Stasis does not push it.
Free and behavioral
- Closed-window protocols during peak pollen season
Closes the dominant pollen entry route, especially during morning peaks and low-wind days when outdoor counts run highest. The audit names the seasonal driver active for your address.
Controls pollen infiltration only; year-round pet and mite exposure is unaffected and needs the filtration and humidity tiers.
Stasis solves what you won't change. Families keep the pet, keep the carpet, and let the pollen ride in on the breeze. None of that has to change for your exposure to drop. The audit measures which allergens are active in your specific home and engineers around the choices you have already made, instead of asking you to choose between your family's lifestyle and how your body feels indoors. We do not diagnose you and we do not advise on pets, laundry, or where you sleep. We report what is measurable and recommend the engineering that lowers it.
Common questions
Are hypoallergenic dog or cat breeds better for allergies?
No. In a study of 196 so-called hypoallergenic dogs against 160 standard dogs, allergen levels were not lower, and the hypoallergenic hair samples actually carried more dog allergen. All cats produce Fel d 1 in their skin glands, so even hairless breeds keep making it. The hypoallergenic breed is a marketing category, not a scientific one.
Do I need an allergy test before the audit can help?
No. Most people already know their pattern: symptoms around dogs, or pollen season wrecking them. The engineering recommendations are the same whether or not you carry a formal IgE diagnosis, because dust-mite enzymes irritate the airway lining in everyone exposed, not only sensitized people. The audit identifies which allergens are active in your home and what reduces them. It is not a clinical screening tool.
If a pet leaves, does the allergen go with it?
Not for a long time. Cat allergen sticks to walls, upholstery, and mattresses and stays detectable for more than 20 weeks after the cat is gone. Dust-mite fecal pellets persist for weeks after the mites die. This is why source removal alone rarely fixes the problem and why filtration, encasements, and humidity control carry the work.
Why does lowering humidity matter so much for dust mites?
Mites cannot drink liquid water; they absorb it from the air through their cuticle. Below about 50% relative humidity they lose water faster than they can replace it and die off, while above that range their populations grow. Holding the bedroom there is the single most reliable lever on the mite reservoir. In dry, AC-reliant climates it often already sits there, and the audit verifies it with a 7-day reading.
Can a HEPA purifier handle everything on its own?
It handles airborne particles, which means it works well on pet allergen and the lung-depositing fraction of pollen and mite allergen. It does not reach the allergen settled in your mattress and carpet. Encasements and sub-50% humidity address that reservoir. Filtration plus humidity control plus encasements is the combination that works; one alone leaves a gap.
Sources
Peer-reviewed
- Sporik et al., 1990 (N Engl J Med; Der p I exposure and childhood asthma)
- Arlian et al., 1999 (J Allergy Clin Immunol; reducing RH to control D. farinae)
- Wan et al., 1999 (J Clin Invest; Der p 1 disrupts airway tight junctions)
- Ogi et al., 2021 (Front Allergy; Der p 1 barrier disruption in allergic and non-allergic patients)
- Heinrich et al., 2015 (PLOS ONE; no confirmed cat-allergen symptom threshold in adults)
- Vredegoor et al., 2012 (J Allergy Clin Immunol; no evidence any dog breed is hypoallergenic)
- Nicholas et al., 2011 (Am J Rhinol Allergy; dog allergen levels in hypoallergenic vs standard homes)
- Bonnet et al., 2018 (Allergy Asthma Clin Immunol; molecular cat allergens, Fel d 1)
- Wood et al., 1989 (J Allergy Clin Immunol; cat allergen persistence after removal)
- Murray et al., 2017 (Am J Respir Crit Care Med; mite-impermeable bedcovers and childhood asthma exacerbations)
- Woodcock et al., 2003 (N Engl J Med; allergen-impermeable bed covers in adults with asthma)
- Maya-Manzano et al., 2022 (Clin Transl Allergy; portable HEPA RCT for mite and pet allergens)
- Léger et al., 2006 (Arch Intern Med; allergic rhinitis and quality of sleep)
- Salo et al., 2018 (J Allergy Clin Immunol; bedroom allergen exposures in US households)
Institutional & standards
- ASHRAE Standard 52.2-2017 (MERV filter rating system)
- AAAAI National Allergy Bureau (pollen station network and counts)
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