Causes of poor air quality such as humidity, drafts, cold windows in the winter or hot windows in the summer, are all lessened by improvements in energy-efficiency.
(Causes of poor air quality such as humidity, drafts, cold windows in the winter or hot windows in the summer; are lessened; by improvements in energy-efficiency)
Causes of poor air quality such as humidity, drafts, cold windows in the winter or hot windows in the summer
are lessened
by improvements in energy-efficiency