US research has found that chemicals in everyday household products are now a key contributor to city air pollution, rivalling some vehicle emissions.
The study, led from Colorado University, focussed on so-called volatile organic compounds (VOCs).
These are contained in petroleum-based products such as cleaning fluids and paints, and when they get into the air can form particles that affect health.
Dr Jessica Gilman said it should not be seen as that remarkable because vehicle fuels are burned (to yield mostly carbon dioxide and water), whereas many of the household products are simply wafted into the air by design.
"Most commonly, they're used as solvents - things like nail polish remover, the hairspray I used this morning; they are used in many cases as cleaning agents like carpet cleaners," the National Oceanic and Atmospheric Administration scientist told reporters.