EDS/SEM CHARACTERISATION OF PARTICULATE MATTER FROM NEW YEAR'S FIREWORKS 2015 AND 2016 IN MUNICH (GERMANY)

摘要

The use of fireworks is associated throughout the world with different celebrations. They range from birthdays up to huge events such as Independence Day (United States) or the festival of Divali (India). In many countries New Year is celebrated with a major fireworks display. Burning of fireworks emits gaseous pollutants and causes pollution by particles in the nanometre and micrometre range [1-3]. These air pollutants often cause serious health hazards [1]. The particle pollution, so-called "particulate matter" (PM), includes inhalable coarse particles with diameter less than 10 μm (PM_(10)), fine particles with diameter under 2.5 μm (PM_(2.5)), and ultrafine particles (UFP) or nanoparticles less than 100 nm. Via the respiratory tract the PM enters the human body. While PM_(10) and PM_(2.5) are mainly deposited in the bronchial tubes, the much smaller UFPs can even reach the alveoli, enter the bloodstream and penetrate into the brain and inner organs. People, who live in large cities are the worst affected by New Year's fireworks. For example, in Munich PM_(10) levels reached 100 μg/m~3 (1.1.2016) and 504 μg/m~3 (1.1.2017) [3], which is 2 and 10 times more than the mean guideline set by the World Health Organization (WHO) of 50 μg/m~3 on average over a 24-hour period [4]. The goal of this study was the chemical and physical characterisation of airborne PM during fireworks display at New Year celebrations 2016 and 2017 in Munich (Germany). For this purpose the airborne particles were collected on 01.01.2016 (sample 1) and 01.01.2017 (sample 2). For comparison also an air sample in the absence of any fireworks was collected on 13.06.2016 (sample 3). For the sample collections carbon coated copper-grids mounted on a polycarbonate filter were used. The samples were analysed by a Zeiss FESEM at 20 kV acceleration voltage and 4-8 mm working distance with in-lens detector (SEM). For energy-dispersive X-ray analysis (EDS) an Oxford INCA energy-dispersive X-ray spectrometer was used. Overall, 150 particles per firework sample were examined. The reference sample (13.06.2016) shows much less particles and thus only few particles were analysed. The firework particles were different in shape and size (Fig. 1 and Fig. 2). A fraction of particles was spherical while other particles had irregular shapes. The sample 2 has significantly higher concentration of particles (Fig. 2). All investigated particles have diameter in the range of 0.03 to 10 μm. Only a few soot particles (3 %) have been found in the samples. 93 % of the particles included potassium and sulphur. Additionally, oxygen, copper, aluminium, silica, chlorine, calcium, bromine, barium, strontium and lead were found in the same particles. Presumably these particles are composed of metal oxide caused by oxygen-producing decomposition of metallic nitrides which are used in the fireworks.