Black Carbon in Bulgaria—Observed and Modelled Concentrations in Two Cities for Two Months

Black carbon (BC) is one of the particulate matter (PM) components that both affects human health and contributes to climate change. In this study, we present the preliminary results of the investigation of BC concentrations in PM2.5 for two Bulgarian cites—Sofia and Burgas. The parallel PM2.5 samplings were organized in October 2020 and January 2021. The Multi-Wavelength Absorption Black carbon Instrument (MABI) was used for the evaluation of light-absorbing carbon. In addition, we compared the observed BC and PM2.5 values to modelled ones and analyzed the spatial distribution over the country, using data from advanced operational chemical transport models (CTM)—the European (regional) air quality system established at the Copernicus Atmosphere Monitoring Service (CAMS). Generally, the observed BC and PM2.5 values were higher in January than in October for both cities. In October, the model underestimated the observed BC concentrations (Sofia—2.44 μg.m−3, Burgas—1.63 μg.m−3) by 17% and 51%. In January 2021, the observed monthly BC concentrations were higher (Sofia—3.62 μg.m−3, Burgas—1.75 μg.m−3), and the bias of the model was less than that in October, with an overestimation of 22% for Sofia. The relative bias for PM2.5 in October (17% for Sofia and −6% for Burgas) was less than the relative bias in January when the model underestimated PM2.5 monthly mean concentrations by 20% (Sofia) and 42% (Burgas). In addition, we also elaborate on two episodes with high observed BC concentrations in view of the meteorological conditions

Meteorology and air pollution experiment at the Black Sea coastal site Ahtopol - 2017

Coastal dynamics is a challenging topic not only for physical processes capturing but also for phenomena related to aerosols exchange and transport. Here we present results of an experimental campaign performed in August 2017 at Ahtopol (Bulgaria) in the frame of Collaboration program between ISAC-CNR and NIMH-BAS research centers. The aim of the campaign was to carry out investigation of air pollution and meteorological conditions at Ahtopol coastal site through collecting aerosols, observing physical parameters, analyzing air-masses circulation and comparing the equipment and methods used by the participating groups. The observation programme of the experiment included measurements to capture both physical and chemical parameters and to reveal the near surface characteristics of sea breeze onset and penetration inland as well as its effect on the aerosol concentration. Particle concentration (number particles/liter in 6 different fractions) was measured with Aerosol and Laser Particle counters. In addition, samples of wet and total deposition were collected. Chemical analysis of collected wet and dry deposition samples and impacted filters was performed and the results obtained were compared with those of previous investigations