In the modern home, it's surprising how many toxins can exist, brought in from outdoors or swirling in the ether from household activities, furnishings and appliances, or condensation and mold, with nowhere to go but to build-up and pollute the air you breathe. As such, ensuring that a house has a healthy airflow and is as toxin-free as possible is paramount. Proper ventilation is key, with a mix of mechanical ventilation systems with high quality particle filters and natural ventilation both playing important roles dependent on the environmental factors inside and outside the home. Air purifiers, air cleaners and certain plants can also help.