Bioaerosols & Asthma

Bioaerosol exposure can cause a range of asthma symptoms. Tell your doctor if any of these occur regularly, especially after spending time in a particular space:

Dust mites are microscopic organisms that feed on shed human skin cells. They thrive in bedding, upholstered furniture, carpets, and stuffed toys — especially in warm, humid conditions. The allergen comes not from the mite itself but from its fecal particles and body fragments, which become airborne when disturbed.

Where they concentrate most: mattresses, pillows, comforters, sofas, and carpeted floors — anywhere people spend time.

• Wash all bedding weekly in hot water (130°F or higher) to kill mites.
• Use allergen-proof covers on mattresses and pillows — these are one of the most effective interventions.
• Keep indoor humidity below 50%; dust mites cannot survive in dry air.
• Vacuum at least weekly with a HEPA-filter vacuum; consider a double-bagged or bagless with sealed canister.
• Remove or reduce wall-to-wall carpeting in bedrooms where possible.
• Wash stuffed animals regularly or place them in a sealed bag in the freezer overnight.

Cats and dogs produce allergens in their skin flakes (dander), saliva, and urine — not just their fur. These allergens are lightweight, sticky, and can remain airborne for extended periods. They also transfer easily: pet allergens are routinely detected in schools, offices, and other spaces where no animals live.

• Keep pets completely out of the bedroom — this is the most impactful single step.
• Run a HEPA air purifier in the bedroom and main living area continuously.
• Bathe pets regularly if your veterinarian recommends it; this can reduce airborne dander load temporarily.
• Vacuum and clean all soft surfaces frequently.
• Wash hands after touching pets and before touching your face.

Cockroach and mouse allergens are found in feces, saliva, shed body parts, and urine. They are particularly important asthma triggers in urban and lower-income housing. Exposure is strongly linked to increased asthma symptoms, hospitalizations, and emergency care — especially in children.

• Store all food (including pet food) in sealed, hard-sided containers.
• Clean up crumbs and spills immediately; avoid leaving dirty dishes out overnight.
• Seal cracks, gaps around pipes, and other entry points with caulk or steel wool.
• Use integrated pest management (IPM) — bait stations and traps rather than sprays, which can themselves irritate airways.
• Reduce clutter where pests can nest.
• Talk to your building manager or housing authority if pests are a persistent problem.

Mold releases spores and chemical compounds that can trigger asthma symptoms even in people who are not classically "allergic" to mold. Exposure to dampness and mold in homes has been associated with wheezing, coughing, and an increased risk of asthma development in children.

• Keep indoor humidity between 30% and 50% — use a hygrometer to monitor.
• Repair all leaks promptly; don't wait.
• Dry wet materials (carpet, drywall, furniture) within 24–48 hours to prevent mold growth.
• Use exhaust fans in bathrooms and kitchens during and after use.
• Discard water-damaged porous materials (drywall, carpet, ceiling tiles) that cannot be thoroughly dried and cleaned.
• For large mold problems (larger than 10 sq. ft.), consult a professional remediation service.

Respiratory viruses — including rhinovirus (the common cold), RSV, influenza, and COVID-19 — are responsible for more than 80% of asthma exacerbations. Viral infections inflame and narrow already-sensitive airways, making asthma significantly harder to control during and after illness.

• Wash hands frequently — especially before eating and after touching shared surfaces.
• Avoid close contact with people who are sick when possible.
• Stay current on recommended vaccinations (flu, COVID-19, RSV if eligible).
• Improve indoor ventilation by opening windows when outdoor air quality allows.
• Consider wearing a high-quality mask (N95, KN95, or KF94) during periods of high respiratory illness spread.
• Contact your doctor early if you develop a cold or respiratory illness — do not wait until symptoms are severe.

No single intervention eliminates all asthma triggers. The most effective approach works in layers, following a clear priority order:

Use this checklist to evaluate your home. Share it with your allergist at your next visit to identify which areas need the most attention.