When those compounds are used at home, they can accumulate on surfaces. V.O.C. levels are two to five times higher indoors than out, according to the Environmental Protection Agency.

When cleaning products are thrown away or washed down the drain, the chemicals they contain, including things like benzene and formaldehyde, which are commonly found in air fresheners, ultimately end up in lakes, rivers and landfills.

Unfortunately, it’s often hard to know what’s in cleaning products because the companies that make them are not required to disclose ingredients. That’s true even for products labeled “green” or “natural.” The Environmental Working Group found that only 7 percent of the 2,000 cleaning products reviewed adequately disclosed ingredients.

So, how can you find out which cleaning products are really green?

Looking for the Environmental Protection Agency Safer Choice label on cleaning supplies is a good first step. The Safer Choice program reviews more than just product ingredients. It also looks at product performance and the sustainability of packaging. Once a product is approved, the E.P.A. conducts regular audits to ensure that standards continue to be upheld.

The Environmental Working Group also rates top green cleaning products.

Another option is to make your own cleaners with everyday household products like white vinegar, baking soda and Castile soap.