It refers to the difficulty of keeping both PM2.5 (dust and pollutants) and CO2 levels low at the same time. Actions that improve one often worsen the other, making balance a key challenge.

A constantly running fan can pull air from other rooms, including spaces where air purifiers are working. This creates negative pressure and draws in untreated air, which raises indoor pollution levels.

Run the exhaust fan only when needed. Always switch it off afterward, especially at night.

Start by keeping shoes outside the house to avoid bringing in dust and dirt. Minimize carpets and clutter, especially in bedrooms, since they trap pollutants. A cleaner, simpler room generally means healthier air.

Use natural cleaning agents like citronella water. Avoid harsh chemicals such as phenol, which can release harmful compounds indoors.

Cooking releases smoke, oil, and fumes. Running the kitchen exhaust fan during cooking ensures pollutants are vented outdoors instead of spreading through the house.

Turn it off once cooking is done. Leaving it on continuously can create negative pressure that pulls untreated air into the home.