How Landfill Odors and Pollutants Enter Your Home

Understanding how pollutants actually enter your home is the foundation of any effective response. Spoiler: there are more pathways than you think, and some of them are completely invisible.

The Physics of Infiltration

Air moves from high pressure to low pressure, always. Two main forces drive outdoor air into your home:

Wind pressure: Wind pushes air against the windward side of your house and pulls it away from the leeward side, creating pressure differences that force air through every gap and crack.

Stack effect: Warm air rises. In winter, your warm interior air rises and escapes through gaps at the top of your home (ceiling, attic, top-floor windows), pulling cold outside air in at the bottom. In summer, the reverse can occur. Either way, your home is constantly exchanging air with the outside—whether you want it to or not.

Your HVAC system also matters. If your ducts run through unconditioned spaces (attic, crawlspace), and they leak—which most do—they can actively pull in outdoor air and distribute it throughout your house.

The Main Entry Points

Doors and Door Frames

The gap between a door and its frame, and the space under the door, are the largest single entry points in most homes. A gap of just 1/8 inch around a standard exterior door is the equivalent of a 6-square-inch hole in your wall.

Electrical Outlets and Switch Plates

This surprises most people. Electrical boxes cut through your wall and connect directly to the wall cavity, which connects to your attic and basement. Air flows freely through them. Every outlet on an exterior wall is a hole in your building envelope.

Window Gaps and Frames

Older windows lose their seal over time. The gap between the window frame and rough opening is often inadequately insulated. Operable windows have moving parts that can never seal as tightly as a fixed window.

Utility Penetrations

Every pipe and wire that enters your home from outside is a potential air pathway. Check around: gas lines, water supply, electrical conduit, cable TV/internet, HVAC refrigerant lines. Each penetration should be sealed with foam or silicone caulk Amazon.

The HVAC System: Hidden Highway

If your heating and cooling system has leaky ducts or a poorly sealed air handler, it can pull large volumes of outdoor air into your living spaces. Signs include: rooms that won't reach set temperature, high energy bills, and notable pressure differences when the system runs. A professional energy audit (often subsidized by utilities) can identify duct leakage with a blower door test.

Detecting Infiltration Yourself

On a cold, windy day, run your hand around door frames, outlet covers, and window edges. A lit incense stick works even better—watch the smoke. Any movement toward the wall indicates a draft. A real-time PM2.5 monitor will also show spikes when wind pushes from the landfill direction—direct evidence of infiltration.