Prediction of airborne pollen and sub-pollen particles for thunderstorm asthma outbreaks assessment

When exposed to convective thunderstorm conditions, pollen grains can rupture and release large numbers of allergenic sub-pollen particles (SPPs). These sub-pollen particles easily enter deep into human lungs, causing an asthmatic response named thunderstorm asthma (TA). Up to now, efforts to numerically predict the airborne SPP process and to forecast the occurrence of TAs are unsatisfactory. To overcome this problem, we have developed a physically-based pollen model (DREAM-POLL) with parameterized formation of airborne SPPs caused by convective atmospheric conditions. We ran the model over the Southern Australian grass fields for 2010 and 2016 pollen seasons when four largest decadal TA epidemics happened in Melbourne. One of these TA events (in November 2016) was the worldwide most extreme one which resulted to nine deaths and hundreds of hospital patient presentations. By executing the model on a day-by-day basis in a hindcast real-time mode we predicted SPP peaks exclusively only when the four major TA outbreaks happened, thus achieving a high forecasting success rate. The proposed modelling system can be easily implemented for other geographical domains and for different pollen types.

Characterization of VOC sources in an urban area based on PTR-MS measurements and receptor modelling

In this study, the concentrations of volatile organic compounds were measured by the use of proton transfer reaction mass spectrometry, together with NO x , NO, NO2, SO2, CO and PM10 and meteorological parameters in an urban area of Belgrade during winter 2014. The multivariate receptor model US EPA Unmix was applied to the obtained dataset resolving six source profiles, which can be attributed to traffic-related emissions, gasoline evaporation/oil refineries, petrochemical industry/biogenic emissions, aged plumes, solid-fuel burning and local laboratories. Besides the vehicle exhaust, accounting for 27.6 % of the total mixing ratios, industrial emissions, which are present in three out of six resolved profiles, exert a significant impact on air quality in the urban area. The major contribution of regional and long-range transport was determined for source profiles associated with petrochemical industry/biogenic emissions (40 %) and gasoline evaporation/oil refineries (29 %) using trajectory sector analysis. The concentration-weighted trajectory model was applied with the aim of resolving the spatial distribution of potential distant sources, and the results indicated that emission sources from neighbouring countries, as well as from Slovakia, Greece, Poland and Scandinavian countries, significantly contribute to the observed concentrations.

[Preliminary results of experimental reanastomosis of uterine horns of laboratory rats after sterilization]

The goal of the launched studies was to analyse, on an experimental model, the histophysiological properties of the segments of the rat's uterine horns after end-to-end anastomoses by the microsurgery technique. Sexually mature females of the laboratory Winster strain were used. Eight weeks after the uterine horns were ligated for sterilization, reanastomosomes were performed. One group of animals was given hydrocortisone for 8 days postoperatively. The results of the observation of the sites of anastomosis has shown that the use of the microsurgery technique allows an almost ideal reconstruction of the cut segments. The absence of chronic interstitial changes in the endometrium, a decreased presence of connective-muscular tissues within the stroma and the RES system cells in animals having received hydrocortisone in relation to those who have not -- all this indicates that the postoperative use of hydrocortisone decreases both the "reactive" growth of the connective tissue and the RES system cells.