Micro- and nano-sized particles of polytetrafluoroethylene (PTFE) were used as model (reference) particles to study the biological effects of plastic pollution. Since the PTFE molecule contains fluorine, considered as an “atomic marker” sharply distinguishing it from other common plastics, micro- and nano-particles of PTFE have a specific crystalline structure and are, therefore, well identified by the methods of polarized light microscopy (POL), Raman microspectroscopy (micro-Raman), and energy-dispersive spectroscopy (EDS). Examples of PTFE particles detection in hemolimph of the cockroach Blatella germanica, in hemolimph of the larva and in faecal pellets of imago of a fly Lucilia sp., in the stomach and hingat of brine shrimp Artemia salina, and in association with cell wall of green unicellular alga Chlorococcus sp. are provided. The presented results strongly suggest that PTFE particles can be detected and identified in the biological medium using the method of “atomic markers”, polarization microscopy and Raman spectroscopy.

Atopic asthma is characterized by the presence of sensitization to common aeroallergens, which tends to have a worse prognosis than non-atopic asthma. The objectives were to determine the prevalence of aeroallergens sensitization in the Lebanese pediatric asthmatic population and determine the relationship between allergens sensitization (indoor and outdoor) and age, area of residence and altitude. A sample, consisting of 919 asthmatic children (aged 1 to 18 years, from 2010 until 2017), underwent skin prick testing (SPT) with 21 common allergens: 5 grasses (cocksfoot, sweet vernal-grass, rye-grass, meadow grass, timothy), Parietaria, olive, Dermatophagoides pteronyssinus and Dermatophagoides farina (DP-DF), dog and cat dander, Alternaria longipens, Aspergillus fumigatus and nidulans, Cupressaceae, pine, German cockroach, and 4 cereals (oat, wheat, barley, maize). Seven hundred fifty-two patients had positive SPT. The distribution of sensitization was as follows: DP-DF 59%; 5 grasses 34%; 4 cereals 33.9%; cat 29.9%; Alternaria 27.9%; Parietaria 23%; dog 21.9%; olive 20.5%; Aspergillus mix 18.6%; Cupressaceae 18.2%; pine 17%; cockroach 15.3%. House dust mites sensitization was frequent at lower altitude (< 900 m) (56.3%) and in the whole country (a median prevalence of 53.05%) except for the Beqaa region (negative HDM in 82.4%). Non-atopic asthma was more frequent in early childhood (40.5% at 1–4 years vs 11.2% at 11–18 years). The sensitization rate increased with age, starting at 5 years. Higher age (aOR = 1.24) and altitude less than 900 m compared with ≥ 900 m (aOR = 2.03) were significantly associated with the presence of aeroallergens in children. House dust mites and grasses are the most common allergens in Lebanese asthmatic children. Non-atopic asthma is more frequent at early age. Lebanese children with asthma showed a polysensitized pattern starting at 5 years.