In the contact

If the parquet is fresh, then everything is fine, but if the parquet is made under varnish, then the old varnish itself is burned out, from high pressure and temperature in the contact zone of abrasive material with the floor. There is practically no dust, but there are combustion products, and there is nothing to do, except to open the window.The most poisonous old varnish is an acidic Moscow Soviet varnish, you have to work almost in a gas mask.