Portable air-conditioners usually require a vent in a window or a wall to allow hot air to be vented out.

I have observed that a business located at an HDB void deck usually sets the exhaust hose at the base of a window, such that the hot air is vented out onto the passageway.

When a pedestrian walks by, he is likely to receive a gust of hot air to his face.

Do the authorities have any guidelines on whether the open ends of exhaust hoses should be positioned to discharge hot air onto pedestrian passageways?

Portable air-conditioners are usually fitted with air filters to eliminate airborne particles. Some also have built-in air purifiers.

If such portable air-conditioners are used on hazy days, will the vented hot air contain hazardous particles such as PM2.5?

The United States Food and Drug Administration advises that soiled N95 respirators be placed in a plastic bag before being binned. The individual should also wash his hands after handling the used mask.

When air purifiers and air-conditioners are heavily utilised during hazy weather, could contamination occur when one is changing filters?

If so, how should a person avoid contaminating himself and the environment when replacing and discarding used filters?

Tan Lay Hoon (Ms)