Almost 1,400 gas-flaring complaints have been made to the environmental regulator about a chemical plant in Fife since the beginning of the year.
NHS Fife said complaints to Sepa's helpline indicated an increase in concern from residents living near Mossmorran about health concerns.
The health board said it was now working with Sepa to analyse the data.
Residents have complained of hayfever-like symptoms, red itchy eyes, headaches and breathing difficulties.
Louise Biggerstaff, 47, told the BBC Scotland news website how she moved to nearby Crossgates 14 years ago and started noticing symptoms.
She said: "I thought it was strange that I had started getting hayfever because I had never had it before.
"But it wasn't until the really big flaring episode at Easter this year that it dawned on me that it was the flaring that was causing it."
'Concerned for children'
She said she gets burning eyes and cannot catch her breath during flaring.
"How I would describe the feeling is the burning that can catch the back of your throat when you are cleaning with bleach mixed with another cleaning product," she said.
"I can now correlate my health symptoms with each flaring event. I didn't notice a pattern at first but I do now as the flaring has become more frequent and more intense.
"I've also seen the Sepa inspectors testing in nearby fields but it's been up wind which is no good for monitoring the fumes we are having to breath in.
"I'm concerned for my children as I'm scared what they are breathing in and what the long term effects are."
Susan Fraser, 40, moved to Crossgates near the plant four years ago.
She said: "My seven-year-old son uses his inhaler about three times a year but now he has to use it every day during flaring events and normally he only needs two puffs but during a flaring he needs 10 puffs.
"Something in the fumes is triggering his asthma and he also gets itchy sore eyes.
"I'm really angry about this and I'm now looking into buying an air purifier for his room but they are about £300, which I shouldn't have to pay.
"I've looked at the air quality reports and have noticed they only talk about monitoring particle size. There is no mention about what is in the smoke."
James Glen, chairman of the Mossmorran Action Group, said: "We have had hundreds of reports from people concerned about their health.
"People are suffering breathing difficulties, headaches and sore eyes but they are also concerned about rare cancers rates as well as common cancers."
An NHS Fife spokeswoman said: "NHS Fife takes any instance where there may be public health concerns very seriously and we continue to work closely with Sepa and Fife Council on public health issues.
"We recognise that during incidents of unplanned flaring, complaints to Sepa's helpline indicate an increase in concern amongst residents about health concerns.
"NHS Fife's public health team are working with Sepa to analyse these health related complaints and identify the issues raised.
"This information will be made available to the public when the analysis is complete, which will be in September.
"GPs would normally contact public health if they had concerns about public health issues affecting their patients and NHS Fife public health team has not received any calls from healthcare providers during recent flaring episodes.
"As usual, we would advise anyone experiencing symptoms of ill health to contact their GP."
In 2018, Sepa (the Scottish Environment Protection Agency) issued final warning letters to both operators about flaring, which it said was "preventable and unacceptable".
The Mossmorran site is shared by ExxonMobil Chemical Ltd and Shell Fife NGL.
Ian Buchanan, Sepa's chief officer, compliance, said: "Sepa remains in daily contact with both operators at Mossmorran during the shutdown of ExxonMobil Chemical Limited and we are undertaking regular monitoring visits in the area.
"Last week we took further steps to lead to a reduction in the impacts of flaring on local communities through the permit variations we served on both companies."
He said Sepa had been monitoring air quality since the plant began flaring on 12 August.
"Our monitors remain in place in in Lochgelly, Auchertool and Donibristle and all our data continues to show no breaches of air quality standards due to Mossmorran.
"Sepa has published six reports on air quality monitoring during flaring at Mossmorran this year.
"We will continue to work with partner agencies, including NHS Fife and Fife Council, to provide information to the public."
'No significant risk'
Stuart Neill, external affairs manager for ExxonMobil said: "A recent study by independent air quality specialists Wood Group indicated that, even when based on 'extremely unlikely worst-case scenarios' 'Fife Ethylene Plant is unlikely to have an impact on air quality and human health'.
"Furthermore, independent air quality monitoring has, over many years, consistently shown that the Fife Ethylene Plant and flaring pose no significant risk to the health of the community."
Teresa Waddington, Shell Fife NGL plant manager, said: "We monitor our emissions in line with our pollution prevention permit and we provide information to a local air quality monitoring review group.
"This group, which includes representatives of the local authorities, continues to find and report annually that emissions from the plants at Mossmorran pose no significant risk to the health of local residents.
"We are aware of further assessment being done by NHS Fife and Sepa and we are very open to any evidence being shared, and further dialogue."