ISSS608 2018-19 T1 Assign Clara Chua Kiah Hwii Task 3
Sofia: So Smoggy
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Bulgaria is a major electricity generator for the Eastern European block and has different types of power plants ranging from nuclear plants to hydroelectric plants to thermal power plants. The thermal power plants contribute to air pollution and as we map the various power plants in Bulgaria, we see that there are 3 power plants in the vicinity of Sofia City province. There are 2 in Sofia City itself (Sofia Iztok, Sofia) and one in a nearby province, Pernik. Mapping this back to an overview of the various sensor readings, we can see that the Sofia Power Plant, which has a capacity of 130MW, is close to one of the areas that has a higher concentration of PM10 (from citizen data). Pernik is close enough to consider effects of transboundary pollution - we would need to examine more closely wind direction, wind speeds, and other factors that may carry particulate matter across to Sofia.
Meteorology and Topography have complex interactions - even with much study, meteorologists are hard pressed to make accurate predictions as there is so much variability. It is difficult to therefore map the interactions between the different meteorological data, and a novice attempt at understanding the data is shown below.
The topography plot shows that the city-centre of Sofia is at a lower elevation than the surrounding areas to the southwest, and that it is in fact in a valley, surrounded by higher elevations. In a normal air pattern, air cools as it rises, allowing mixing to occur. Where Sofia is, exists an inversion layer, where the air warms with height. The cooler air is trapped at the surface, because it is more dense than the air mass above it. This is a double whammy for Sofia because, this means that particulate matter is trapped below the inversion layer, if there isn't enough wind speed to carry it away, and because it is colder, and retains the cold longer, citizens will need to ensure they have sufficient sources of heat, which in many cases in Bulgaria, is the burning of wood or other fossil fuels, which produce pollution.
This could explain the worst day in Sofia (27 - 28 Jan 2018). The system had a few cold days, reaching a minimum of -14 degrees Celsius, and with low wind speeds, and a low dewpoint, which meant that the air was likely to be saturated with particulate matter, but had nowhere to go, and trapped more pollutants in the area.
The EEA data and citizen air quality data show similar data and while the citizen air quality data needs to be cleaned with a fine tooth comb (and some common sense), it helps to give a broader view of the situation in Sofia and more data points for analysis to be done. Certainly more can be done to match the metereological data with the existing data points to see if there are more patterns that can be discerned and to alleviate the issues, but citizens can't do much about the weather. What they can do is to reduce the amount of fossil fuel burned during winter. These are social engineering solutions, where central heating should be affordable and available to citizens to reduce that source of air pollution in winter.
