Volatile organic compounds and gaseous pollutants from building materials, cleaning products, and appliances accumulate in poorly ventilated spaces. Understanding these invisible threats is the first step to cleaner, safer air.
Formaldehyde deserves specific attention because it is ubiquitous in building materials and has well-documented health effects. Composite wood products — plywood, particleboard, MDF — used extensively in cabinetry, furniture, and subflooring use urea-formaldehyde resins that off-gas continuously, declining over years but never fully stopping.
The EPA’s reference concentration for formaldehyde is 0.008 mg/m³ (approximately 6.5 ppb). Levels in newly constructed or recently renovated homes can exceed this significantly, particularly in tightly sealed, heavily air-conditioned spaces. Symptoms at moderate levels include eye and throat irritation, headaches, and exacerbation of asthma. Formaldehyde is classified as a known human carcinogen by IARC.
Carbon monoxide (CO) is produced by incomplete combustion — gas appliances, generators, grills, and vehicles. It is colorless, odorless, and rapidly lethal at high concentrations. In South Florida, hurricane preparation creates specific CO risks: portable generators operated indoors or in garages during and after storms are a leading cause of CO poisoning fatalities in the state.
Carbon dioxide (CO₂) accumulates in occupied spaces when ventilation is inadequate. At 1,000 ppm — easily reached in a crowded, poorly ventilated meeting room — CO₂ causes measurable cognitive impairment. At 2,000+ ppm, occupants experience fatigue, headache, and difficulty concentrating. CO₂ monitoring is increasingly used as a proxy for ventilation adequacy in commercial and institutional settings.
South Florida’s year-round pest pressure — roaches, termites, rodents, mosquitoes — means that pesticide application indoors is more frequent than in most of the country. Residual pesticide compounds from spraying, fogging, and termite treatment can persist in indoor air, dust, and on surfaces long after application.
Organophosphate and carbamate pesticides can remain active on treated surfaces for weeks to months. In homes with young children who spend time on floors, or with pets, residual pesticide loads are a legitimate IAQ concern. Integrated pest management (IPM) approaches that minimize chemical use and prioritize exclusion are the preferred strategy for reducing pesticide-related indoor exposure.
Radon — covered in detail on its own page — is a radioactive gas and a significant long-term cancer risk. Though less common in South Florida than in higher-geology-risk regions, it remains testable and mitigable.
Ozone can enter buildings from outdoors during high-ozone episodes, and is also generated indoors by some air-cleaning devices and laser printers. At concentrations above roughly 70 ppb, ozone irritates airways and can trigger asthma. Some ionizing air purifiers generate ozone as a byproduct — California’s CARB certification for air cleaning devices provides a useful benchmark for avoiding ozone-generating equipment.
We’re here to help. Whether you’re trying to learn about pollutants in your home or workplace, or just want to point us toward a topic you’d like us to cover — we’d love to hear from you.
South Florida Indoor Air is an independent educational resource dedicated to helping our community breathe better and make informed decisions about the air inside their spaces.