Four academics have died of lung cancer in a smog-ridden city yet to be declared a disaster zone despite chronic air pollution.

Professor Raviwan Olanratmanee, dean of Chiang Mai University's Faculty of Architecture, passed away from lung cancer this month, making her the fourth lecturer at the university to die of the disease.

Assistant Professor Phichaapa Pisutseranee, a lecturer at the university's political science faculty, expressed her condolences to Raviwan's family in an online post on April 4.

She said three other teachers have also succumbed to lung cancer since 2022. They were Associate Professor Dr Phanuwan Chanthawankoon of the biology department who died in March 2022, Associate Professor Mongkol Rayanakorn of the chemistry department who died last September, and Dr Kritthai Thanakritsombat of the faculty of medicine who died last December.

While officials confirmed earlier this month that lung cancer rates have surged by 50 per cent in Thailand due to smoke from farm burning blanketing the country.

Bungling Thai Prime Minister Srettha Thavisin was derided last month when he refused to declare the region a disaster zone 'because it would hurt tourism'.

Furious Assistant Professor Phichaapa said: 'How many more losses must we endure before we can address the issue of burning and pollution effectively?'

Raviwan's husband Jittakorn Olanratmanee said she began showing symptoms of lung disease last year. The couple initially attributed her illness to long Covid, but when Raviwan began coughing up blood, they sought medical help at the Chiang Mai University Faculty of Medicine.

The diagnosis was grim, revealing Raviwan had stage 4 lung cancer.

Jittakorn said: 'I want to highlight to the government that we have been grappling with this issue for a long time.

'However, since it hasn't directly affected us significantly, we may not have attached much importance to it. But one day, if someone in our family, or we ourselves were to develop lung cancer, we would immediately recognise the severe impact of PM2.5.'

He urged authorities to take the air pollution crisis seriously, citing his wife's case as an example of its impact.

Pongpol Yodmuangcharoen, a politician involved in drafting a Clean Air Act, expressed his condolences to Raviwan's family.

He said in a statement: 'This draft of the Clean Air Act may be an important hope for society to solve the dust problem. To give an update on the status of the working team, from a total of 11 meetings, we are studying 50 to 60 sections out of the 102 proposed sections, but none have been finalised yet.

'It is important to gather input from political and academic perspectives. But I also recognise that we are racing against the clock as the air we breathe becomes more dangerous.'

Chiang Mai is consistently among the world's most polluted areas, according to Swiss air quality company IQAir.

Despite the carcinogenic smog shrouding the region, Prime Minister Srettha Thavisin has refused to declare it an emergency zone 'to protect tourism'.

He wrote online: 'What will happen after the announcement is it will affect the number of foreign tourists when tourism has just recovered in the wake of Covid-19.

'Chiang Mai province will definitely lose tourists who plan for short- and long-term stays. That is what we are worrying about.'

He added that travel insurance will not cover cases in areas declared disaster or emergency zones.

Officials said that lung cancer deaths in the north of the country - the area hit worst by PM 2.5 pollution -have soared from 20.3 per 100,000 people in 2010 to 30.7 in 2019.

Associate Professor Chalerm Liewsisakul of Chiang Mai University's Faculty of Medicine said the last decade has seen a 'notable deterioration in air quality in the region correlating with an increase in lung disease cases'.

Medics said that lung cancer in young people had also risen in the areas blighted by air pollution which 'suggests a direct link to prolonged exposure to PM2.5 particles'.

The study by Chiang Mai University also looked at emphysema patients in one region of the city. It claims that exposure leads to cellular changes, 'hinting at the potential for genetic mutations and cancer development'.

They said that they had seen a spike in respiratory problems, with serious conditions like emphysema, coronary heart disease, and strokes becoming more common during high pollution periods.

The study claimed that there is a 1.6 per cent rise in deaths for every rise of 10 microgrammes of PM 2.5 particles per cubic metre of air.

The World Health Organisation (WHO) puts the safe levels of PM2.5 at five microgrammes but Chiang Mai has become the worst in the world in recent weeks, often recording levels as high as 100 microgrammes per cubic metre - more than 20 times the safe limit.

It has been consistently rated the worst city in the world for air pollution by Swiss group IQAir.

Dangerous levels of deadly PM 2.5 particles - which cause cancer and other debilitating illnesses - are recorded every year in Thailand between December and April when farmers across Southeast Asia burn waste crops to clear their land.

The rudimentary method, known as 'slash and burn', is quicker and cheaper than modern machinery, leaving relatively poor landowners unwilling to heed environmental and health concerns over economic necessity.

Despite paying lip service for several years, politicians have failed to stop individuals from burning their land due to it being cheaper and easier than modern farming methods.

In March 2023, the Public Health Ministry of Thailand reported that around 1.3 million people in the country had been unwell due to the rising levels of air pollution. Officials said 200,000 residents were hospitalised in a single week.

Researchers from Peking University in Beijing, China, found that exposure to PM 2.5 air pollution is associated with an increased risk of lung cancer.

In December, Dr Krittai Thanasombatkul from Chiang Mai - one of the world's worst cities for air pollution - died of lung cancer. He had previously blamed PM 2.5 microdust particles for his condition.

The New York State Department of Health says PM 2.5 also increases the risk of heart disease, asthma, and low birth weight.

Medics from South Korea published research in the National Institute of Health in the United States that said the pollutant increases the risk of stroke, ischemic heart disease, chronic obstructive pulmonary disease (COPD), lung cancer, and other illnesses such as immune deficiency and even obesity.