After Midsummer Lights, Shadows Remain in the Environment: FTMC Scientist Studies the Impact of Bonfires on Air Quality

 

The team works on airborne fine particles, their composition, formation and impact on the environment, as well as developing advanced research methods and technologies to monitor climate change, assess air quality, and create a safer environment. One of the most recent and relevant studies is currently being carried out by Agnė Minderytė, a PhD student of Byčenkienė.

 

Together with her colleagues from the University of Warsaw, Agnė invites us to look at the forthcoming Midsummer (known in Lithuania as St John's Eve) not only as a celebration, but also as a scientific question: how much particulate matter do we emit into the atmosphere when we burn bonfires?

 

Although data analysis is still in its early stages, Minderytė says it is already clear that Midsummer bonfires emit a much higher amount of soot than on other days - and this prompts us to think about how we can keep old traditions alive while being environmentally friendly.

 

 

 

 

"I am just finishing my Erasmus+ traineeship at the University of Warsaw, where my colleagues and I, under the supervision of Prof. Dr Iwona Stachlewska, have initiated a study on the traditional Lithuanian and Polish festivals - St. John's Day and Majówka (celebrated on 1-3 May). Both are mass celebrations accompanied by bonfires or barbecues, which involve intensive burning of wood or charcoal.

 

Interestingly, these celebrations can be seen as national-scale experiments that produce similar types of particulate emissions over a large area in a short period of time (one evening or night)," says Minderytė.

 

She and her colleagues at the FTMC noticed several years ago that on St John's Eve in Vilnius, the concentration of black carbon (also known as soot) rises. In Warsaw, the same trend was observed, with a rise during Majówka. This gave rise to the idea of carrying out a comparative study on how the traditions of different countries affect air quality and aerosol particle properties.

 

The FTMC partners in Warsaw specialise in remote sensing technologies, using the Light Detection and Ranging (LIDAR) laser system to analyse how aerosol particles are distributed in different layers of the atmosphere. "This not only allows us to see what is happening “right here”, but also to gain a deeper understanding of how smoke affects the entire atmospheric column and even its thermal balance. This is a great example of interdisciplinary collaboration - where local traditions become a field of study for global environmental issues," says the physicist.

 

 

 

 

The Lithuanian-Polish study is still in its early stages, with data being actively analysed and a scientific paper being written. According to Minderytė, there are a number of aspects that need to be further verified in order to ensure that the results are accurate and complete. However, the data so far already shows a clear trend:

 

"During St John's Eve and Majówka, the amount of light-absorbing black carbon (soot) in the atmosphere increases dramatically. Looking at the effects of the festivals over the last four years, the trend is the same in both cities, with black carbon concentrations increasing by a factor of 3-4 compared to background concentrations in June (Vilnius) and April and May (Warsaw).

 

As well as reducing air quality, these particles absorb sunlight and turn it into heat. Black carbon gets its name because it behaves like a black body, absorbing all the light that hits it in the visible range of light. The absorbed light energy is converted into heat, and this heat stays in the atmosphere and contributes to its warming.

 

This distorts the natural thermal equilibrium in the Earth-atmosphere system. In other words, it changes how much energy the atmosphere emits and absorbs. This leads to melting of glaciers, changes in cloud structure and precipitation distribution. This is what these particles mean for climate change.

 

A more important factor for air quality is that the particles produced by combustion processes are extremely small and can enter internal organs through the lungs, carry other harmful compounds absorbed (deposited) on the particles, and cause chronic diseases. So these particles have a double impact: pollution poses both climate and health risks, but through different mechanisms."

 

 

 

 

According to the scientist, today, we are increasingly looking for solutions to reconcile the holidays with environmental sustainability. So there is no need to give up Midsummer - we could just celebrate it in a more environmentally friendly way, so that old traditions and modern consciousness can go hand in hand.

 

"St John's Eve is not only about fire, but also about communion, a connection with nature and culture. It is too categorical to abandon bonfires, which have been part of us for centuries. But it is important to know that bonfires, though short-lived, are localised sources of pollution.

 

The important thing is not to condemn but to share knowledge. When we understand the impact, we can make conscious choices to preserve the tradition and at the same time respect the environment. If people are looking for cleaner ways to celebrate, it is always possible to choose a smaller bonfire, to use dry wood, which leads to a more efficient burning process and less aerosol particles. In addition, communities organise joint Midsummer events and symbolic bonfires, which are also a possible way to enjoy the festival without having to build yet another bonfire," suggests Minderytė.

 

 

 

Dr Steigvilė Byčenkienė, Head of the FTMC Department of Environmental Research, echoes her PhD student: "As the smoke rises, so does the question: is it possible to celebrate in a different way - in a way that keeps the fire burning but does not harm? Agnė's research is not just about pollution. It's about a bridge between knowledge and values, between ancient rituals and modern awareness. Not to abandon tradition, but to rethink it - with respect, creativity and responsibility.

 

I believe that this initiative will be not only an important scientific contribution to environmental research, but also a gentle invitation to dialogue: between nature and man, between the past and the future, between how we celebrate - and how we would like to celebrate tomorrow."