The city skyline disappeared in a haze of bushfire smoke overnight as Melbourne suffered its lowest air-quality rating since records began.

Much of Victoria is breathing air rated “poor”, “very poor” and even “hazardous” today, due to 19 bushfires still burning across the state.

The smoke engulfing Melbourne has travelled from East Gippsland and the air quality is expected to remain very poor to hazardous into tomorrow, according to the Victorian Environmental Protection Authority (EPA).

The city’s air quality is currently rated very poor but reached hazardous levels at around 12am.

The EPA has warned the air could be dangerous – particularly to vulnerable groups such as children under the age of 14, adults over the age of 65, people with heart and lung conditions (including asthma) and pregnant women.

It advises staying indoors, if possible, closing windows and doors, visiting air-conditioned public spaces such as libraries and shopping centres, following asthma and other respiratory-health plans, and speaking to a doctor or nurse if you experience difficulty breathing or a tightness in your chest.

Ordinary paper dust-masks, handkerchiefs and bandanas won’t filter out fine particles or smoke. But properly fitted filter masks with a P2-plus rating will, and can be bought from hardware stores or online.

Up-to-date information can be found on the EPA’s AirWatch website, which gives overall air-quality ratings, as well as the current PM2.5 level, referring to the concentration of pollutants with a diameter of less than 2.5 micrometres (about three per cent of a human hair) in the air.

The ratings are based on data measured at stations across the state and general observations, along with satellite imaging, data from the Commonwealth Scientific and Industrial Research Organisation (CSIRO) and Bureau of Meteorology (BoM) weather forecasts.

Get update via the EPA’s website or Twitter account.