When scented wax melts are heated, they release fragrant compounds called terpenes – the same types of molecules that give pine trees their distinctive smell or make lemons smell citrusy.

Fragranced products and cooking generate harmful nanoscale pollutants indoors, posing potential health risks. Purdue ...

But bringing that pine scent or other aromas indoors with the help of chemical products — yes, air fresheners, wax melts, floor cleaners, deodorants and others — rapidly fills the air with ...