Opening the window at night to cool the room during summer months is a widespread habit. However, experts warn that especially in big cities, this is not always a safe choice for health.
Medianews.az, citing lent.az, reports that according to pulmonologist Valeri Simon, there is no universal answer regarding whether to open or close the window; everything depends on the quality of the air in the area where you live.
According to him, even during nighttime in large cities, fine dust particles, nitrogen dioxide (NO₂) emitted by cars, pollen, and noise can enter the room from the street.
The specialist notes that many people do not consider that air pollution can remain at a high level even at night. Fine dust particles and nitrogen dioxide can penetrate the deep layers of the respiratory tract and cause inflammatory processes.
Air pollution also affects sleep
Research shows that air pollution decreases sleep quality, causes frequent awakenings during the night, and can exacerbate respiratory diseases.
This situation is a more serious problem especially for people with allergies or asthma. Pollen can cause nasal congestion, sneezing, coughing, watery eyes at night, difficulty falling into deep sleep, and even nighttime asthma attacks in these individuals.
Closed window is not an ideal solution either
Experts state that keeping the window completely closed does not solve the problem either. In a poorly ventilated room, the levels of carbon dioxide (CO₂) and humidity increase. Because the room temperature rises during hot summer nights, the body struggles to maintain a normal body temperature, which also worsens sleep quality.
An air purifier can help
In homes without air conditioners, using an air purifier is considered beneficial. This device can reduce the amount of dust particles, fine dust, and other pollutants in the room.
Experts emphasize that an air purifier does not fully replace proper ventilation. However, it can be a useful alternative on days when the air is polluted or dust particles are widespread.
What did the European study show?
The European Sleep Index prepared for the year 2026 evaluated sleep conditions in 25 large European cities.
The study showed that nighttime noise and air pollution are the main factors hindering comfortable sleep. Cities with higher air pollution and nighttime noise showed lower results regarding sleep quality.
Monitoring air quality is important
Experts advise people suffering from asthma and allergies to regularly follow official warnings about air quality. Especially when the levels of pollutants such as PM10 dust particles, nitrogen dioxide (NO₂), sulfur dioxide (SO₂), and ozone (O₃) are high, it is not recommended to keep windows open for long periods. In such cases, the room should be ventilated early in the morning when the air is cleaner or during hours with less pollution.