Whats the black dust that seems to accumulate on houses?

Question

I was cleaning my new (old) apt, and the balcony was just covered in this black greyish powder.

I remembered that hotel rooftops ive been to are the same.

Black stuff. Really fine particles.

Soot?

Haven't checked outside the city

kirsten · Answer

You've probably noticed it's worst after a rain that doesn't fully wash things down. That black powder is a mix of diesel exhaust particles and tire dust from the roads, and the humidity here basically bakes it onto surfaces. If you want to keep it from caking up so fast on your balcony, try wiping it down with a vinegar-water mix instead of just water. It cuts through the grime better.

sannaulmer · Answer

It's mostly PM2.5 from diesel trucks and incinerators, but what really makes it stick to everything is the high humidity. You notice it more in older buildings because they don't have the same air sealing as new high-rises. A good microfiber cloth and some mild detergent will get it off the balcony, just be prepared to do it every few weeks.

cornelia · Answer

yeah its prob just soot from all the cars and construction around here. the pm2.5 filters in my air purifier get dark real fast so that checks out

Neu aus Tokyo