Sydneysiders have been urged to “stay vigilant” and remain indoors as the city’s air pollution surpasses cities like Bangkok and Mumbai.
The city awoke on Tuesday to a thick blanket of ‘unhealthy’ smoke and a heavy scent as almost 50 blazes burn across the state, with more than half of those uncontained.
Air quality in the city has been listed by NSW Environment as poor and unhealthy for sensitive people due to particles.
However, the northwest suburbs have been deemed hazardous for all residents.
The suburb of Rouse Hill has a ‘very unhealthy’ rating of 236 - higher than air pollution in Bangkok, Mumbai, Huai’an and Faridabad, India - which was deemed the second most polluted city in the world in 2018 by The World Health Organisation.
Moree, in northern NSW, has a ‘unhealthy’ rating of 195.
In comparison, New York’s current air quality is 20, or ‘good’, while Hobart in Tasmania, well away from the bushfires, has an air quality rating of 5.
Hazardous affects on residents’ health
The air pollution during bushfires can include small particles of carbon, as well as dirt, dust and noxious gasses, according to Dr Ivan Hanigan from the School of Public Health.
“The airborne particles from bushfires are especially damaging, either directly on the respiratory system through their inhalation and impacts in the lungs; or by affecting the cardiovascular system, and even our brains, causing toxicity and systemic inflammation.
“There may even be life-threatening sepsis from airborne microbes associated with bushfire and dust events,” he said.
Dr Hanigan said research shows “bushfire smoke and dust is linked to population-level mortality, especially for deaths from cardiovascular diseases.”
“We also found associations between bushfire smoke events and hospital admissions for respiratory conditions.”
To minimise the effects of the smoke, residents are urged to stay indoors, avoid vigorous exercise and to wear a mask over their face.
Why NSW bushfires smoke is trapped in Sydney
BOM Meteorologist Ellie Blandford told Yahoo News Australia the smoke’s presence in Sydney can be attributed to two things – a north-westerly wind moving the smoke from a fire in the Hawkesbury area over the city, and an inversion that trapped it within the low level areas overnight.
The haze from the 140,000-hectare fire will improve with a southerly wind change on Tuesday afternoon, but winds will continue to blow some of the bushfire smoke toward the city.
Most of the state’s east coast remains under severe or very high fire danger ratings.
"It's fair to say all of these fires have got the potential to present real challenges today," Rural Fire Service NSW Chief Commissioner Shane Fitzsimmons said on Tuesday.
Weather conditions will pose problems for the 1400 firefighters on the ground battling flames fanned and spread in different directions by "really problematic" gusts reaching up to 65km/h.
"Not only have we got these high temperatures, the mid to high 30s, dry atmosphere, we've got this real mix of converging winds," he told ABC News.
Parts of the state under severe fire danger are Greater Sydney, Greater Hunter, Illawarra-Shoalhaven, Southern Ranges and Central Ranges fire regions.
These regions, along with the Northern Slopes and North Western regions, are also under a total fire ban.
Following weeks of difficult bushfire conditions and last week's 'catastrophic" warnings, Mr Fitzsimmons said it was crucial people didn't take anything for granted.
"The last thing we want is lethargy, complacency or fatigue to set in when it comes to monitoring these conditions," he said.
Six lives and 530 homes have been lost since the NSW bushfire season hit some weeks ago, with more than 420 homes destroyed in the past fortnight alone.
Some 1.6 million hectares of land have been lost so far - more than the entire 1993/1994 bushfire season.
Emergency Services Minister David Elliott on Monday said the biggest risk this week would be firefighters becoming fatigued.
A DC10 air tanker has been drafted in from North America to help drop up to 38,000 litres of water and retardant on blazes, and efforts will be bolstered by help from New Zealand firefighters, Mr Elliott said.
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