Air pollution maps for specific situations
Maps for the surface concentrations of air pollutants, and for the depositions have been created based on the results from the modelling system WRF-CMAQ. The model output is in terms of hourly values for more than 20 pollutants, meteorological variables and deposition parameters, so it becomes important to select representative time periods for their visualization.
Selection of meteorological situations
The selected periods for the purposes of the project represent 3 categories:
- “mixed” periods (the time interval includes days without rain (dry) and some following days with rain of different intensity);
- “rain” only periods (the time interval includes only days with precipitations over the region);
- “dry” only periods, characterized by favorable meteorological conditions for moderate to intense air pollution over the region.
The periods have different duration, from 4 to 10 days. The synoptic situation for each
period is briefly outlined. The maps are presented as animated image files, so that the
temporal variation for a given period can be followed.
Three different types of maps are shown – respectively for surface concentrations (ozone,
nitrogen oxide, nitrogen dioxide, sulphur dioxide, particulate matter with diameter < 10
µm and (PM10) particulate matter with diameter < 2.5 µm (PM2.5)), the dry deposition of
nitrogen dioxide, ozone, sea salt aerosols and PM10, and the wet depositions of ozone, sea
salt aerosols and PM10. The sea salt aerosols are estimated as the sum of chlorine (Cl) and
sodium (Na) aerosols with d < 10µm.
1. Dry periods, followed by rains with low pH-values (pH less or around 5)
1a. August: 8–15.08 (predominantly dry) + 16-17.08 (rain in Burgas about 30 lm-2
and in Ahtopol – 10 lm-2). The anticyclone conditions in the dry period are associated
with high summer temperatures, well developed breeze circulations along the coast. The following
rainy period is associated with southwestern intrusion of air masses and the passage of a cold
frontal system from southwest towards northeast.
Ozone concentration O3
Nitrogen Oxide concentration NO
Nitrogen Dioxide concentration NO2
Sulphur concentration SO2
Concentration of particulate matter with diameter < 10 µm (PM10)
Concentration of particulate matter with diameter < 2.5 µm (PM2.5)
Dry deposition of NO2
Dry deposition of O3
Dry deposition of PM10
Dry deposition of sea salt
Wet deposition O3
Wet deposition of PM10
Wet deposition of sea salt
1b. September: 8–13.09 (dry) + 14-18.09 (rain mainly in Ahtopol – about 5 lm-2
in total). The dry period is in low-gradient pressure conditions over the country, the rainy
period is associated with the passage of a frontal system from west towards east.
Ozone concentration O3
Nitrogen Oxide concentration NO
Nitrogen Dioxide concentration NO2
Sulphur concentration SO2
Concentration of particulate matter with diameter < 10 µm (PM10)
Concentration of particulate matter with diameter < 2.5 µm (PM2.5)
Dry deposition of NO2
Dry deposition of O3
Dry deposition of PM10
Dry deposition of sea salt
Wet deposition O3
Wet deposition of PM10
Wet deposition of sea salt
2. Dry periods followed by rains with high pH-values (pH around 6.5)
2a. June: 01–03.06 (relatively dry) + 04-05.06 (rain Burgas – 10 lm-2
and more in Ahtopol – about 39 lm-2 in total). The first part of the period
is characterized by relatively cold weather with short precipitations over the country.
The following rainy period is associated with the passage of an African cyclone over
Southern Bulgaria, bringing moderate to intense rains especially in the region.
Ozone concentration O3
Nitrogen Oxide concentration NO
Nitrogen Dioxide concentration NO2
Sulphur concentration SO2
Concentration of particulate matter with diameter < 10 µm (PM10)
Concentration of particulate matter with diameter < 2.5 µm (PM2.5)
Dry deposition of NO2
Dry deposition of O3
Dry deposition of PM10
Dry deposition of sea salt
Wet deposition O3
Wet deposition of PM10
Wet deposition of sea salt
2b. July-Aug: 26–31.07 (dry) + 01-02.08 (rains with low intensity -
Burgas – about 3 lm-2, Ahtopol - 1 lm-2). The first part
of the period is characterized by the passage of a frontal system and cyclone
from west towards east over Bulgaria. However, the cross-border region remains
without precipitations. The following rainy period is associated with the passage
of a frontal system of a cyclone moving from the western part of the Balkan Peninsula.
Ozone concentration O3
Nitrogen Oxide concentration NO
Nitrogen Dioxide concentration NO2
Sulphur concentration SO2
Concentration of particulate matter with diameter < 10 µm (PM10)
Concentration of particulate matter with diameter < 2.5 µm (PM2.5)
Dry deposition of NO2
Dry deposition of O3
Dry deposition of PM10
Dry deposition of sea salt
Wet deposition O3
Wet deposition of PM10
Wet deposition of sea salt
3. Rainy periods, with intense rains, or flooding in southeastern Bulgaria
3a. July: 15-17.07 (local flooding in Southeastern Bulgaria). A cyclone
passing from west to east is resident over the country in the days before the
period, bringing intensive rains in the western Bulgaria. In the days 15-17.07.,
the cyclone is moving over eastern Bulgaria. Measured pH values in Ahtopol and Burgas
are below 5.5.
Ozone concentration O3
Nitrogen Oxide concentration NO
Nitrogen Dioxide concentration NO2
Sulphur concentration SO2
Concentration of particulate matter with diameter < 10 µm (PM10)
Concentration of particulate matter with diameter < 2.5 µm (PM2.5)
Dry deposition of NO2
Dry deposition of O3
Dry deposition of PM10
Dry deposition of sea salt
Wet deposition O3
Wet deposition of PM10
Wet deposition of sea salt
3b. July: 19-25 July (with intense rains on 23-24 .07. in southeastern
Bulgaria and in northern Turkey). The measured precipitation on 24.07 is 22 lm-2
in Ahtopol, in Burgas the rain quantity is much smaller – around 6 lm-2).
Ozone concentration O3
Nitrogen Oxide concentration NO
Nitrogen Dioxide concentration NO2
Sulphur concentration SO2
Concentration of particulate matter with diameter < 10 µm (PM10)
Concentration of particulate matter with diameter < 2.5 µm (PM2.5)
Dry deposition of NO2
Dry deposition of O3
Dry deposition of PM10
Dry deposition of sea salt
Wet deposition O3
Wet deposition of PM10
Wet deposition of sea salt
3c. September: 02-03.09 (rain in the Turkish part of the region) + 05-07.09
(rains in southeastern Bulgaria with flooding in Sozopol). The situation is caused
by the passage of a Mediterranean cyclone, bringing intensive rains all over the country.
Measured pH-values in Ahtopol and Burgas are in the range 5-6.
Ozone concentration O3
Nitrogen Oxide concentration NO
Nitrogen Dioxide concentration NO2
Sulphur concentration SO2
Concentration of particulate matter with diameter < 10 µm (PM10)
Concentration of particulate matter with diameter < 2.5 µm (PM2.5)
Dry deposition of NO2
Dry deposition of O3
Dry deposition of PM10
Dry deposition of sea salt
Wet deposition O3
Wet deposition of PM10
Wet deposition of sea salt
3d. October: 23-31.10 (140 lm-2 Ahtopol rain in the period on
25-27 Oct). The situation is characterized by the passage of a Mediterranean
cyclone, which remains blocked by a high pressure system situated to the east
(over the Caspian Sea). Intensive rains in southern Bulgaria, storm conditions
with high waves and strong winds along the seaside at Ahtopol. 24h sums of
rain quantity at the seacoast are between 50 and 160 lm-2). Measured
pH-values in Ahtopol are acidic (below 5.6), in Burgas – alkaline (about 6.4).
Ozone concentration O3
Nitrogen Oxide concentration NO
Nitrogen Dioxide concentration NO2
Sulphur concentration SO2
Concentration of particulate matter with diameter < 10 µm (PM10)
Concentration of particulate matter with diameter < 2.5 µm (PM2.5)
Dry deposition of NO2
Dry deposition of O3
Dry deposition of PM10
Dry deposition of sea salt
Wet deposition O3
Wet deposition of PM10
Wet deposition of sea salt
4. Dry autumn – periods with temperature inversions favorable for high air pollution
4a. November: 1-10.11. The first two days (1-2.11.) are characterized by
anticyclonic type of autumn weather with low clouds and fogs in the valleys,
on 6.11 a cyclone from west is passing over the country bringing clouds and
rains in western and central Bulgaria. By the end of the period (10.11.) the
flow is light from southwest, foggy conditions along the seaside.
Ozone concentration O3
Nitrogen Oxide concentration NO
Nitrogen Dioxide concentration NO2
Sulphur concentration SO2
Concentration of particulate matter with diameter < 10 µm (PM10)
Concentration of particulate matter with diameter < 2.5 µm (PM2.5)
Dry deposition of NO2
Dry deposition of O3
Dry deposition of PM10
Dry deposition of sea salt
Wet deposition O3
Wet deposition of PM10
Wet deposition of sea salt
4b. November: 23 – 29.11. A slowly moving Mediterranean cyclone is passing
from west to east over the country on 24.11. In its rear part the flow is cold
leading to decrease in the surface temperatures.
Ozone concentration O3
Nitrogen Oxide concentration NO
Nitrogen Dioxide concentration NO2
Sulphur concentration SO2
Concentration of particulate matter with diameter < 10 µm (PM10)
Concentration of particulate matter with diameter < 2.5 µm (PM2.5)
Dry deposition of NO2
Dry deposition of O3
Dry deposition of PM10
Dry deposition of sea salt
Wet deposition O3
Wet deposition of PM10
Wet deposition of sea salt
