Is your house a disgusting swamp of peril and sickness? The latest everything-is-terrifying news is the suggestion this week that dust and other particles around the home can be “obesogens” and stealthily cause us to become dangerously overweight.

The suffix -gen or -ogen (from the Greek for birth; compare “genesis”) indicates that something is being produced. An “immunogen” is any substance that produces an immune response in an organism. The substance originally known as “burnt air” or “mephitic air” was christened nitrogen after it was found to be present in nitric acid.

In our day the headline-making -ogens are usually carcinogens (cancer-generating), such as bacon and, um, obesity. If “obesogens” catch on, the health-conscious will rightly wonder if there are any molecules still left that don’t make us sick. One of biology’s best jokes, after all, is that the very air we breathe helps to kill us, because oxygen (“acid-generating”, so misnamed by the chemist Lavoisier, who thought that it formed all acids) is so reactive.

The calmest approach is probably just to assume that everything we encounter is a causer of death, or thanatogen.