In This Guide
We spend most of our time indoors—especially in apartments where opening windows isn't always practical or possible. Yet most of us give little thought to what we're breathing. The air inside your apartment can contain dust, allergens, volatile organic compounds (VOCs), and other particles that you don't see but that affect your daily comfort.
This guide provides an evidence-based overview of indoor air quality without fear-mongering or medical claims. Our goal is to help you understand what's in your air and make informed decisions about whether and how to improve it.
Why Indoor Air Quality Matters
Indoor air can be different from outdoor air in significant ways. Buildings trap and concentrate certain substances while filtering out others. In apartments specifically:
- Limited ventilation means pollutants can accumulate
- Shared HVAC systems can circulate air between units
- Cooking, cleaning, and other activities add particles and gases
- Building materials and furnishings can emit compounds over time
- Neighbors' activities (smoking, cooking) can affect your unit
Some people notice symptoms like stuffiness, odors, or discomfort in spaces with poor air quality. Others may not notice anything. Either way, understanding your environment helps you make informed choices.
What Affects Indoor Air Quality
Ventilation
How much fresh outdoor air enters your space is one of the biggest factors. More ventilation generally dilutes indoor pollutants, but it also brings in outdoor air (which may have its own issues like traffic pollution or pollen).
Sources of Pollutants
Everything from cooking to cleaning to simply existing adds particles to the air. The number and intensity of pollution sources in your space directly affects air quality.
Humidity
Both very high and very low humidity can cause issues. High humidity encourages mold and dust mites; low humidity can irritate airways and increase dust.
Building Characteristics
Age of the building, HVAC system quality, air sealing, and materials used all play roles. Newer buildings may be more airtight (less ventilation); older buildings may have more infiltration but also older materials.
Common Indoor Pollutants
Particulate Matter
Tiny particles suspended in air. Includes dust, pollen, pet dander, mold spores, and cooking smoke. Different sizes are classified as PM10 (particles under 10 microns) or PM2.5 (under 2.5 microns). Smaller particles can penetrate deeper into the respiratory system.
Volatile Organic Compounds (VOCs)
Gases emitted from various sources including cleaning products, paint, furniture, and building materials. Common VOCs include formaldehyde, benzene, and toluene. "Off-gassing" from new products is a major source.
Carbon Dioxide (CO2)
We exhale CO2, so it accumulates in occupied spaces with poor ventilation. High levels don't pose immediate danger but can indicate inadequate ventilation and may cause stuffiness or difficulty concentrating.
Allergens
Dust mites, pet dander, pollen, and mold can trigger reactions in sensitive individuals. These are particles that air purifiers can help capture.
Odors
While not always harmful, unpleasant odors affect comfort. Sources include cooking, pets, neighbors' activities, and building issues.
For more detail, see our Common Indoor Air Pollutants guide.
Assessing Your Air Quality
Subjective Assessment
Start with your own observations:
- Does your space feel stuffy or fresh?
- Are there persistent odors?
- How quickly does dust accumulate?
- Do you notice any symptoms that improve when you leave?
Air Quality Monitors
Consumer-grade monitors can measure PM2.5, CO2, humidity, and sometimes VOCs. They're not laboratory-accurate but can identify trends and help you understand your environment better. See our Air Quality Monitors Guide.
Professional Testing
For specific concerns (like mold or radon), professional testing may be warranted. This is typically more expensive but more accurate.
Improving Your Air Quality
Source Control
The most effective approach is reducing pollution at the source:
- Use range hood when cooking
- Choose low-VOC cleaning and household products
- Allow new furniture to off-gas before bringing indoors
- Remove shoes at the door to reduce tracked-in particles
- Keep humidity in check to discourage mold and dust mites
Ventilation
When outdoor air quality is good:
- Open windows for cross-ventilation when possible
- Use bathroom and kitchen exhaust fans
- Consider a window fan to increase air exchange
See our Apartment Ventilation Guide.
Air Purification
Air purifiers with HEPA filters can effectively capture particles. Activated carbon helps with some gases and odors. The right size purifier for your space can make a noticeable difference, especially in bedrooms where you spend significant time.
See our Air Purifiers Guide.
Regular Cleaning
Dust, vacuum (with HEPA filter), and clean surfaces regularly to reduce accumulated particles. Wash bedding weekly in hot water to reduce dust mites.
The 80/20 Approach
For most apartments, a few simple actions provide the biggest benefit: use exhaust fans when cooking, keep humidity reasonable, run a HEPA purifier in the bedroom, and clean regularly. Perfection isn't necessary.
Frequently Asked Questions
It depends on location and conditions. Indoor air often has higher concentrations of certain pollutants (VOCs, dust, CO2) due to limited ventilation, while outdoor air may have more traffic pollution or pollen. Neither is universally "worse"—they're different.
Not necessarily. Many people live comfortably without one. Air purifiers are most helpful for those with allergies, pets, or limited ventilation options. If you're satisfied with your air quality and don't have specific concerns, you may not need one.
Use exhaust ventilation when cooking. Cooking generates significant particulate matter, and range hoods that vent outside remove these particles far more effectively than any air purifier. It's simple, effective, and often overlooked.