A study released this week by Proceedings of the National Academy of Sciences of the United States of America concluded that "roads dominated the sources of microplastics to the western United States, followed by marine, agriculture and dust emissions".
Microplastics- particles smaller than 5 millimeters- come from a number of sources. Plastic bags and bottles released into the environment break down into smaller and smaller bits. Your washing machine is another major source: When you launder synthetic clothing, tiny microfibers slough off and get flushed to a wastewater treatment plant. That facility filters out some of the microfibers, trapping them in "sludge", the treated human waste that's then applied to agricultutal fields as fertilizer. That loads the soil with microplastic. A wastewater plant will then flush the remaining microfibers out to sea in the treated water. This has been happening for decades, and because plastics disintegrate but don't ever really disappear, the amount in the ocean has been skyrocketing.
Sources of microplastics in the air :: and how we can think about our own actions in response:
- Roads :: tiny bits of tires slough off and get propelled into the air by highway speeds :: makes a case for driving less, consuming less + depending on local products rather than trucked-in food and other goods as much as possible
- Marine :: plastic garbage breaks down into smaller + smaller pieces...and plastic microfibers shed when polyester/nylon/acrylic clothing are made + washed...both get washed out to sea + blow into the wind with sea spray :: makes a case for cutting synthetic fibers out of our closets + for using as little plastic packaging as possible
- Agriculture :: plastic microfibers from washing + producing synthetic-fiber clothing get applied to agriculture fields as fertilizer + blow off in dust :: makes a case for cutting synthetic fibers out of our closets
These same plastics continue to cycle endlessly, since they don't completely biodegrade. We continue to increase our plastic manufacturing by a rate of 4% per year...even though we know better now. This makes the case for widespread legislation that works to decrease the manufacture of plastic + plastic fibers. The time is now.