The heating season changes the air not only outside. At home it changes too: drier, with the smell of dust from radiators, sometimes with smoke from neighbours or from the kitchen.
The first thing that helps is ventilation. Short but sharp: open the window fully for five to ten minutes rather than leaving it ajar for hours. The air changes, and the walls do not cool down. Morning and before bed are the best moments.
Second, the sources. A kitchen extractor that vents air outside, rather than recirculating it, removes more than an open window during cooking. Third, dust: wiping radiators and windowsills with a damp cloth once a week is easier than fighting it across the flat later.
If someone in the household smokes, the main step is not to smoke indoors at all. Ventilation and extraction do not remove second-hand smoke completely, and it settles on furniture and fabrics.
And finally, humidity. Winter air is dry, and a humidifier helps the airways work better. But it has to be cleaned, or it becomes a source of mould itself.
A useful question for tonight. When did I last air out a room properly, rather than leaving the window ajar?
When home measures are not enough. Constant dry eyes, a cough that will not clear, or worsening allergies — raise it with a doctor. For urgent symptoms call 103 or 112.