The smoky haze engulfing Sydney could be causing long-term health damage to residents, and experts say it will only get worse if climate change isn't stopped.
Thick fog is blanketing the city and its wider suburbs as bushfires continue to rage in northern, southern and western areas of New South Wales.
On Tuesday, the levels of ultra-fine PM2.5 particles, which are small enough to enter the bloodstream and lungs, were 13 times the accepted safety level, 7 News Australia reported.
It resulted in the New South Wales government warning people with lung or heart conditions to stay indoors.
Atmospheric chemistry expert Dr Gabriel da Silva told 7 News inhaling the particles can lead to "increased incidences of chronic diseases, cancers and neurological illnesses", even in healthy people.
He said advice to stay inside only works for a short time because indoor air quality without ventilation deteriorates over time.
Dr da Silva said the smoky haze may be "the new norm and may get worse" as the climate continues to heat up.
Respiratory physiologist from Swinburne University professor Bruce Thompson said the haze should be a "massive wake up call".
"Sydney's air quality is now in the top 10 worst in the world. In a country like Australia, how is this okay?"
Sydney residents continue to share images on social media of the foggy city, and some even complained of tasting the thick smoke.
