Thomas here--I got really interested in DIY Air Purifiers while living in Beijing and suffering from the awful air pollution.

Since then, I've started shipping low-cost DIY purifiers to help people in China get clean air, and I've been publishing open-source data from tests on tests on tests.

Do plants remove particulate?

I think this question is interesting because several people have asked me if they still need a purifier if they have plants in their home.

Lots of websites confidently rank plants by their effectiveness at removing air pollutants, so it’s easy to skip the question of DO plants actually work and focus on WHICH plants work.

If I have plants in my apartment, is my air safe?

But what does the data say? One way to test this is to compare a room with plants versus without plants. I tested an army of plants in the Smart Air office in Beijing. I also review tests from plant experiments and real-world setups here.

But here’s an even simpler way of asking this question. I have hundreds of days of data on PM2.5 air pollution from my Beijing apartment, which is full of plants. This can answer a slightly different question: in a home with lots of plants, are particulate levels safe?

This can at least test a strong version of the plant hypothesis. If people are correctly using plants to get clean air in their home, the particulate levels in my apartment should be low.

Data

The bedroom of my Beijing apartment is 15m2, and there are two large spider plants, an asparagus fern, and other plants.

I collected data on particles .5 microns and 2.5 microns and above with a Dylos DC1100 particle counter.

I collected data before turning on any purifiers when I got home in the evening, usually around 8-11pm. Windows were always closed.

The data covers 365 days from September 2013 to January 2015. Here's the .5 micron data:

That's a lot of particulate! But how does that compare to “safe?” The World Health Organization’s annual limit is 10 micrograms per cubic meter, which is roughly equivalent to 1,000 of 0.5 micron particles on the Dylos. Studies have found health damage even below 10 micrograms, but it’s at least a good start.

Se sovrapponiamo quel limite ai dati della mia stanza, possiamo vedere che quasi tutti i datapoint sono al di sopra del limite:

Quindi, come minimo, sono sicuro di poter dire a chi vive in Cina: anche se avete più piante nella vostra stanza, i livelli di particolato sono molto probabilmente non sicuri.

Domande senza risposta

Questo test è un buon inizio, ma lascia aperte diverse domande:

1. Le piante hanno qualche piccolo effetto sul particolato?

È possibile che le piante nella mia stanza stiano rimuovendo una certa quantità di particelle, ma questo piccolo effetto è sopraffatto dall'aria sporca che penetra dall'esterno.

2. C'è qualche tipo speciale di pianta che rimuove molte particelle?

3. Come sarebbe questo negli Stati Uniti, dove i livelli di particolato all'aperto sono molto più bassi?

Spira sicuro!