It sounds terrible . What will happend in the future?! The research doesn't differentiate between seasons , and every one knows how polluted the air is in the winter when everyone is heating their home and apartament.
One more reason to look to an electrically heated future. Where I live the air becomes unpleasant in winter as some neighbours heat their homes by burning what i can only assume are old tires and horse carcasses.
In the future electric cars and heat pumps will improve the situation.