The unprecedented “dirty haze” blanketing eastern Australia has triggered a spike in emergency department presentations, ambulance call-outs and pleas for workers to stay home as bushfires continue across NSW and Queensland.

NSW Ambulance fielded 2330 calls for help with asthma or breathing difficulties over the past week – 30 per cent more than an average week.

Over the same period, hospitals across the state saw a 25 per cent increase in emergency department presentations for respiratory issues, with 1140 presentations, the biggest spike occurring in the hardest-hit southwestern Sydney area.

The NSW environment department said this season’s bushfire emergency has caused “some of the highest air pollution ever seen in NSW”, with hazy conditions “the longest and the most widespread in our records”.

Players at the Australian Open golf championship underway in Sydney’s south were affected by the smoke, with New Zealander Ryan Chisnall – an asthmatic – resorting to wearing a surgical face mask as conditions deteriorated on Thursday afternoon.

Sydney’s air quality index registered registered levels of pollutants on a air with Beijing.

NSW Health environmental health director Dr Richard Broome says people with asthma, emphysema and angina should avoid outside activity. Face masks provide little protection.

“NSW Health continues to recommend that people with these conditions should avoid outdoor physical activity when there’s smoke around,” Dr Broome said in a statement on Friday.

The main concern with the smoke is minuscule PM2.5 particles which are so tiny they pass through most masks.

An above-average number of people are going to hospitals or calling an ambulance for breathing problems for the third week in a row amid NSW’s bushfire crisis. Photo: Getty

NSW Health said on its website that smoke from bushfires was made up of small particles, gases and water vapour.

“The particles are very small – up to 1/30th the diameter of an average human hair – and are not visible to the human eye.

“The gases in bushfire smoke include carbon monoxide, carbon dioxide, nitrogen oxides and volatile organic compounds,” it read.

“A P2 mask does filter out these particles but is only effective if there is a good fit and an air-tight seal around the mouth and nose,” Dr Broom said.

Australian golfer Matt Jones described the smokey conditions as “awful”, telling Nine’s Wide World of Sport  he’d never endured anything like it, and hoped his kids were tucked up inside their hotel room.

“I’m not sure what the forecast is but the smoke’s not good at all.

“It’s tough to see your golf ball when you’re out there playing, where it finishes.

Ryan Chisnell of New Zealand was forced to wear a face mask on Thursday afternoon. Photo: AAP

“Your eyes do burn up. I’ve got that cough like you’ve got something in your lungs, phlegm in your lungs or whatever, but yeah it’s not fun.

Vets also experienced a rise in patients, with dogs and cats turning up at veterinary clinics and hospitals across Sydney with severe asthmatic attacks, breathing difficulties and nausea.

NSW’s peak union body took to social media on Friday morning urging employers to give non-essential workers the option of staying home.

“Our cities and towns have been choked in an unprecedented dirty haze. Sydney has the worst air quality of any world city.

“That’s why all employers must give non-essential workers the option of staying indoors or staying home. We must take the health risks seriously,” Unions NSW posted on Twitter.

State secretary Mark Morey added: “Medical research tells us today’s poor air quality coupled with heat is a deadly combination. We want employers and the NSW government to look after their workforces today”.

The NSW Bureau of Meteorology has continued to warn residents across NSW and Queensland the poor air quality due to bushfire activity would continue for several days.

Sydney’s east and southwest were rated as “hazardous” for air pollution on Friday, while the northwest had “fair” conditions.

-with AAP