Computer Simulations of Air Quality and Bio-Climatic Indices for the City of Sofia

Air pollution is responsible for many adverse effects on human beings. Thermal discomfort, on the other hand, is able to overload the human body and eventually provoke health implications due to the heat imbalance. Methods: The aim of the presented work is to study the behavior of two bio-climatic indices and statistical characteristics of the air quality index for Sofia city—the capital of Bulgaria for the period 2008–2014. The study is based on the WRF-CMAQ model system simulations with a spatial resolution of 1 km. The air quality is estimated by the air quality index, taking into account the influence of different pollutants and the thermal conditions by two indices, respectively, for hot and cold weather. It was found that the recurrence of both the heat and cold index categories and of the air quality categories have heterogeneous space distribution and well manifested diurnal and seasonal variability. For all of the situations, only O3 and PM10 are the dominant pollutants—these which determine the AQI category. It was found that AQI1, AQI2, and AQI3, which fall in the “Low” band, have the highest recurrence during the different seasons, up to more than 70% in some places and situations. The recurrence of AQI10 (very high) is rather small—no more than 5% and concentrated in small areas, mostly in the city center. The Heat index of category “Danger” never appears, and the Heat index of category “Extreme caution” appears only in the spring and summer with the highest recurrence of less than 5% in the city center. For the Wind-chill index category, “Very High Risk” never appears, and the category “High Risk” appears with a frequency of about 1–2%. The above leads to the conclusion that both from a point of view of bioclimatic and air quality indices, the human health risks in the city of Sofia are not as high

Editorial for the Special Issue “Atmospheric Composition and Regional Climate Studies in Bulgaria”

The Special Issue “Atmospheric composition and regional climate studies in Bulgaria” is focused on the following two problems, which are of great societal and scientific importance: [...

Assessment of the national emission reduction strategies effects for Bulgaria (2020–2029 and after 2030) on surface FPRM and CPRM concentrations

Bulgaria has developed national emission reduction strategies for the period from 2020 to 2029 and the years after 2030, in accordance with EU Directive 2016/2284. Our fundamental aim in this study is to assess the effects of the strategy on the PM near surface concentrations in Bulgaria. All the simulation was done by the modeling system U.S. Environmental Protection Agency (US EPA) Models-3 for 2008 to 2014 period and with 9 km horizontal grid resolution for the selected region – Bulgaria. The meteorological background that was used is with 1°x1° resolution from the National Centers for Environmental Prediction (NCEP) Global Analysis Data. There are 5 emission scenarios structured: 2005 emissions (reference period), 2020–2029 emissions projected with existing measures (WEM) and with additional measures (WAM), projected after 2030 WEM and WAM emissions, as parallel calculations were performed with all of the scenarios. Making parallels between the concentrations, with different scenarios simulated, gives the possibility to evaluate the national emission reduction strategies’ effect

Assessment of the national emission reduction strategies effects for Bulgaria (2020–2029 and after 2030) on surface FPRM and CPRM concentrations

Bulgaria has developed national emission reduction strategies for the period from 2020 to 2029 and the years after 2030, in accordance with EU Directive 2016/2284. Our fundamental aim in this study is to assess the effects of the strategy on the PM near surface concentrations in Bulgaria. All the simulation was done by the modeling system U.S. Environmental Protection Agency (US EPA) Models-3 for 2008 to 2014 period and with 9 km horizontal grid resolution for the selected region – Bulgaria. The meteorological background that was used is with 1°x1° resolution from the National Centers for Environmental Prediction (NCEP) Global Analysis Data. There are 5 emission scenarios structured: 2005 emissions (reference period), 2020–2029 emissions projected with existing measures (WEM) and with additional measures (WAM), projected after 2030 WEM and WAM emissions, as parallel calculations were performed with all of the scenarios. Making parallels between the concentrations, with different scenarios simulated, gives the possibility to evaluate the national emission reduction strategies’ effect

Modelling of the heat and the cold risks in Sofia and Varna – preliminary results

According to future climate projections, the expected thermal stress environmental conditions will get worse if the authorities do not apply appropriate measures for mitigation and adaptation to these changes. The health issues concerning air pollution and extreme temperatures have assumed great importance in recent years. The objective of this study is to estimate the thermal comfort in two of the biggest cities in Bulgaria - Sofia and Varna and their surroundings for the year 2017 by biometeorological indexes. We use computer simulations of the atmospheric parameters that define the thermal comfort indexes, by Advanced Research Weather Forecast Model WRF ARW version 3.9. We performed the simulations on four domains for 2017 with an output frequency of 1 hour. The outermost domain has a horizontal resolution of 9 km and encompasses the Balkan Peninsula. It uses initial and boundary conditions from the 0.25-degree NCEP Final Operational Model Global Tropospheric Analyses datasets with a time-frequency of 6 hours. The estimation of the thermal comfort conditions is performed with characteristics called indexes. The differences in the number of cases between the indexes are due to the specific definitions and the meteorological factors that each of them takes into account. Some of these characteristics have applications depending on the specific thermal conditions

CALCULATION OF SOME OZONE POLLUTION INDEXES FOR BULGARIA

As an active photo-oxidant the atmospheric ozone can cause serious damages to human health and vegetation – forests, crops. That is why the ozone studies are of primary importance for adequate formulation of the environmental policy of the country. A set of integral ozone characteristics (ozone indices) has been developed, which make it possible the ozone pollution impact on human health and ecosystems to be quantitatively evaluated. Calculation and analysis of these ozone indices for Bulgaria are the overall goals of the present work. The US EPA Models-3 system is chosen as a modelling tool. As the NCEP Global Analysis Data with 1 degree resolution is used as meteorological background, the MM5 and CMAQ nesting capabilities are applied for downscaling the simulations to a 9 km resolution over Balkans and 3 km over Bulgaria. The TNO emission inventory is used as emission input. Special pre-processing procedures are created for introducing temporal profiles and speciation of the emissions. The study is based on a large number of numerical simulations carried out day by day for years 2000-2007