Cleanliness may be next to godliness; people mop their homes almost all day. Well, a new study claims that a few minutes of mopping indoors with a scented cleaning product can generate as many airborne particles as vehicles on a busy city street.
The air in homes, schools, and offices may be dirtier than the air outdoors, even in cities with pollution problems. Any kind of burning – candles, incense, cigarettes-is bad. Gas stoves and cooking food also spew unhealthy particles into the air, which can cause asthma and other health problems when breathed in. Other significant sources of indoor air pollution include personal care and cleaning products, whose fragrances contain volatile organic chemicals that react with ozone in the air to form small particles known as aerosols.
A major concern is limonene, which is commonly added to cleaners and furniture polish for removing oil and grease. The lemonscented molecule reacts readily with ozone, an outdoor pollutant that is the main ingredient in smog. When ozone wafts into buildings, it reacts with limonene and similar molecules called monoterpenes, turning them into peroxides, alcohols, and other molecules that grow into airborne particles. Small particles can lodge deep in the lungs, irritating cells and-at high enough exposure -leading to health problems, such as asthma. In vulnerable people, particulate air pollution can cause heart attacks and strokes.
Earlier studies have revealed that cleaning products can generate such pollution. However, not all of these experiments were realistic or detailed. The new study was designed to reveal, minute by minute, what happens with airborne reactions during a typical floor cleaning. Researchers brought their lab instruments into a room with an air volume of 50 cubic meters, about half the size of a semitrailer container. In the morning, they mopped the floor for 12 tq14 minutes with a terpene-based cleaner. Then, they used state-of-the-art instruments to monitor the molecules and particles as they reacted over the next 90 minutes. “This is the first study that really looked at the entire chemical process under realistic indoor conditions,” says co-author Philip Stevens, an atmospheric chemist at Indiana University, Bloomington.