This chemical reaction is common outdoors, where industrial aerosols mix with atmospheric ozone. The resulting SOAs are a major contributor to smog.
"SOAs can come from ozone reactions with numerous sources, especially with compounds called terpenes that produce the scents we associate with cleaners—pine, lavender, and oranges," says Michael Waring, PhD, an assistant professor in Drexel University's College of Engineering. "Limonene is the terpene that makes an orange's smell. It's a very popular scent for cleaning products, so we're taking a closer look at how it reacts indoors—where people are using it in high concentrations."
How many SOAs are being formed? Researchers found that it ranges from five to 100 micrograms per meters cubed, depending on various factors. "For reference, the EPA's National Ambient Air Quality Standard for fine aerosol is an annual average of 12 microgram per meters cubed," explains Waring. "This research is particularly necessary in order to understand health impacts on people who use significant amounts of cleaning products, such as housecleaners or custodians."
"Cleaning house should be an honest chore, not one that is riddled with unpronounceable chemicals that can literally make your head spin, undermine your central nervous system, and contaminate the ecosystem," says Renée Loux, author of Easy Green Living.
Fortunately, it's easy to make your own home cleaners that are totally limonene free. Loux's top ingredients for homemade home cleaners are white distilled vinegar, baking soda, castile soap (like Dr. Bronner's), and hydrogen peroxide. Also consider using organic pure essential oils with natural antiseptic properties, such as cinnamon, clove, lavender, lemongrass, oregano, rosemary, tea tree, and thyme oils.