Thick smoke at a fire in a recycling plant in Maffra street, Coolaroo. Credit:Jason South "Being school holidays we expect there are a lot of children at home and we urge parents to take their children out of the area," Ambulance Victoria state team manager Brett Parker said. Melbourne University professor Peter Rayner said tiny particles from the blaze measuring 2.5 thousandths of a millimetre had the ability to penetrate deeply into people's lungs. "These very little particles can get absorbed into people's lungs and can cause short-term problems. It's associated with asthma but can cause long-term problems such as long-term chronic respiratory disease."

Professor Rayner warned asthma sufferers and anyone with respiratory problems could struggle on Friday as foul-smelling smoke continues to blanket Melbourne. Smoke from the Coolaroo fire was visible from the CBD on Thursday. Credit:Eddie Jim "I'd really be advising people who know they have sensitivity to some irritants to be very careful today and to make sure they have their preventative measures and puffers available." "It could be a rough day for people with breathing problems." Dallas residents Hassan and Helen Halwani and their four children pack their car to flee Dallas late Thursday night. Credit:Darrian Traynor

Residents in suburbs such as Footscray, 18 kilometres south of the blaze, have reported feeling unwell and having headaches because of the smoke. Air quality in the Coolaroo area was rated "very poor" on Friday morning, with high levels of PM2.5 particles. The thick smoke made the going difficult for police. Credit:Jason South When asked about safety concerns for locals, a spokesman for the Department of Health and Human Services' Chief Health Officer said it up to emergency services agencies to evacuate residents. More than 115 household in Dallas were told to evacuate on Thursday evening and thick, acrid smoke continues to blanket the area north of Melbourne. The MFB has said only 22 decided to leave.

The fire at the SKM Recycling plant which began in a bale of plastic is still burning out of control and is expected to last several days. Environment Protection Authority Victoria chief environmental scientist Andrea Hinwood said residents within a one-kilometre radius of the fire were the highest concern. "Yes, you can smell smoke in the city, but the concentrations out around the fire are much higher," she said. "On the ground, our officers are telling us smoke is moving around quite a lot. You can have very good air quality and in the next air quality you can have a very high concentration. It's very challenging for us. "The advice we're providing is exposure reduction. If you can smell it and see it, even in the city, just try and keep inside."

Professor Rayner said the byproducts of plastic burning out of control were concerning. "There's a possibility that some of the products in the smoke are toxic and they can lead to acute disease. People can get sick immediately from the toxins. There might possibly be in the fumes. "When you have a big mix of plastics that's a concern because plastics are chemically very complicated. A fire like this, these things burn at very high temperatures. "In an incinerator, you can make them fairly safe, but in a fire like this, which is much less controlled, you have much less control of what the product of the burns actually are.

"Often it produces a bad odour and that's not necessarily a bad sign in itself but it is a sign that the products of the fire are complicated and some of them could be quite harmful." MFB spokesman Steve Moore said rain expected on Friday was "certainly not going to put the fire out" because it was burning so intensely. Professor Rayner said rain and strong winds would help improve air quality, and the smoke would dissipate quickly once the fire was extinguished. "Rain is a very good cleanser for these things. I noticed yesterday we had fairly strong winds, it was a problem yesterday but it means smoke will get blown away. "The weather might be kind to us. If the air was really still, like the kind of weather we had a week or so ago, it could have stayed around."

Taseen Mollah returned to his Dallas home at 8pm on Thursday evening to see it blanketed in black smoke. He said the ground was covered in soot and he ran into the house with his hands covering his face. "I was finding it hard to even take a breath," he said. "My throat and chest were hurting." His mother and younger brother were inside a bedroom with the doors and windows closed after the smell of the smoke had seeped into the house. "The smell was so bad, it was nauseating and [it] kept getting worse inside the house," he said.

"We closed all the vents inside the house and were getting our stuff ready to leave when the police come to evacuate us." Mr Molah said he and his two brothers and mother will go to stay with relatives nearby. Loading "We just want to get out of here to be honest," he said. With Emily Woods