"If you don't ventilate because it's cold, the pollution increases 10 times"... How can we change the indoor air 'this way'?

The easiest first step is ventilation

Bringing fresh air into your home is the most important step to improving indoor air quality. Well-heated and insulated homes often lack ventilation due to limited outside airflow. Even in winter, open a window for at least 10 minutes to let in fresh air and prevent the growth of bacteria and mold. Ventilate your home especially when using harsh chemical cleaners or painting. A Harvard study found that replacing furniture containing hazardous substances with furniture made from healthier materials reduced airborne toxic dust by 78%. Ensure proper ventilation when purchasing new furniture, and consider using used furniture.

Use chemical-free cleaning products

While cleaning is important for maintaining good health, some cleaning products can actually be harmful. Many household cleaners contain volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs). These can cause headaches, allergies, and respiratory problems, and in the long term, can lead to lung cancer, brain disease, and cardiovascular disease. Even "eco-friendly" products require careful ingredient review, as some eco-friendly cleaners still contain harmful ingredients. Experts recommend using databases like the Cleaning Project Ingredient Safety Initiative (CPISI) to verify ingredient safety before purchasing.

Air purifier installation

No matter how thoroughly you clean, fine dust invisible to the naked eye is difficult to remove. Air purifiers filter out these ultrafine particles and circulate clean air. They are especially effective for people with allergies or households with pets. Air purifiers equipped with HEPA filters remove ultrafine particles with 99.97% efficiency, and those with negative ionization also help neutralize viruses and bacteria. Using the right air purifier can effectively alleviate symptoms of respiratory conditions like asthma and allergies.

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They say it's not good to close the door because it's cold.

When the afternoon sunlight is good, ventilate the house a bit.

The office also has the water turned on for a while.