Clean air is important for health, yet many homes are rife with pollutants.
Household products such as cleaning solvents, waxes, paints and varnishes
often contain volatile organic compounds like benzene and toluene,
which can cause skin irritation, eye damage, neurological disorders and cancer.
Furnishings and carpets, for their part, can slowly release formaldehyde, another carcinogenic molecule.
The presence of these toxins is particularly problematic for children
who spend much of their time indoors and have sensitive lungs.
Air purifiers can help, but houseplants have in recent years been marketed as a more aesthetic alternative.
Amazon, an e-commerce giant, sells plants described as being for "air purification"
alongside more conventional categories such as "low-maintenance" and "pet-friendly".
But how good a job can plants actually do?
Scientists have long known that plants can change the composition of the air around them as they breathe,
turning carbon dioxide into oxygen in the process.
The first good evidence to suggest that they might filter pollutants
at the same time emerged in the 1980s, when NASA exposed
a number of plants housed in small Plexiglas chambers to air contaminated with formaldehyde.
These experiments, which lasted many hours, concluded that spider plants,
among others, were effective at removing the toxin from the air.
Further studies painted a more detailed picture of how such effects were achieved.
Whereas many plants, like pines and yews, have hairy, waxy or rough leaves