Linked to millions of premature deaths each year, vehicle emissions from automobiles have borne much of the responsibility for air pollution levels in major cities. Yet, according to recent research, those levels may also be significantly impacted by common household products such as fragrances and cleaning agents.

A significant amount of air pollution is the result of chemical reactions happening in the atmosphere — the starting point of which is the grouping of hundreds of molecules called “volatile organic compounds” (VOCs) — coming from a variety of sources both man-made and natural, though automobiles are often blamed. However, according to the research published in the journal Science, the VOCs released by vehicle fuels have declined thanks to stringent environmental regulations and advances in technology.

After a review of data from energy and chemical production records, researchers determined that the chemicals in everyday household products are now responsible for a greater share of released VOCs — almost twice as much as cars.

Although good news on the vehicle emissions front, researchers believe the study highlights the need to better regulate everyday household products. Among the strategies recommended to consumers in advance of better regulation are choosing fragrance-free cleaning products and limiting the use of air fresheners and scented candles in the home.

The study is published in the journal Science.