Get an AirVisual Outdoor and contribute to collecting millions of data points for the Sofia map to track local air pollution
The link for the air pollution map for Sofia can be found at the top of the main city page. By clicking anywhere on the map icon, a new page will open up which is full of information about air quality at that time.
When the new page is first opened, the viewer will notice that the entire map is a darkish green colour. This is a direct reflection of the state of the current air quality. The meaning behind all the colours used is explained in the legend at the foot of the page. The colours range from pale green to dark maroon. The darker the colour; the worse the air. The viewer will also notice several coloured circles dotted across the page. These discs show the positions of the ground-level air monitoring stations. The number they display is the US AQI reading. If one of these discs is selected then a new page will open which contains lots of useful information about that area of the city. If they appear to overlap each other, slowly expanding the map will begin to separate them and make them easier to differentiate from each other.
This US AQI reading is endorsed by the World Health Organisation (WHO) and is calculated by measuring the levels of up to six of the most commonly found air pollutants. These are often Particulate Matter (PM2.5 and PM10), ozone, nitrogen dioxide, sulphur dioxide and carbon monoxide. Once calculated, the figure is used as a metric when comparing air standards in other cities across the globe.
In September 2022, this US AQI reading for Sofia was 47 which indicated “Good” quality air. The main measured pollutant was PM2.5 with a level of 11.5 µg/m³. The target figure as suggested by the WHO is 5 µg/m³ so this figure is just over twice that recommended figure.
Immediately below the air pollution map is the number of stations that provide all the data regarding air quality. There are currently nine stations split between three contributors, one is from the educational sector and two remain anonymous.
In order to see the full benefits of all additional information on the air pollution map for Sofia, it needs to be opened in full-screen mode. Once in this style, a list of four options will appear down the left-hand side of the screen.
The first option shows the position of the ground-level air monitoring stations scattered across the city and its environs. By selecting any of the discs, a new page will open which is dedicated to that specific area of the city. The second option reveals the location of any fires which may be burning out of control. There were none to see on the map in September 2022. If there were any active fires, then option four needs to be consulted because it shows the speed and direction that the wind is blowing in. This gives a good indication as to whether or not the city will be affected.
The third option is the most spectacular as it changes the background colour of the map to reflect current air quality. This uses the same set of colours as is used across the entire website. If the colour is too confusing or distracting, then it can be deactivated and the colours will revert to a more subtle palette.
Over on the far right of the screen will be found a table which shows the ranking of world cities according to their level of pollution. The cities with the highest levels are listed first.
Looking below the map can be seen a list of all the stations which have been ranked according to their level of pollution. The dirtiest part of the city is currently around the Vassil Levski Neighbourhood because it shows a US AQI reading of 53 which would be classified as being “Moderate”.
Below this table is a list of the most popular stations according to the number of followers that they each have accrued. The most popular station is currently at Sofia – Mladost because it has gathered almost 75,000 loyal followers. Which is 5,000 more than its nearest rival.
Areas of elevated levels of pollution can easily be found on the air quality map for Sofia. There are two ways to do this, the first is to identify the discs on the map with the darkest colour and highest number. But the easiest way is to look directly below the map where a list is printed which shows the most polluted stations in descending order. The station at the top of the list is currently the Vassil Levski Neighbourhood with a US AQI reading of 53.
The source of the polluted air is not directly shown on the air pollution map for Sofia but official data released by the WHO reveals that the main air pollutants in Sofia are heating by burning wood, coal and waste, road traffic and industry in and around the outskirts of the city.
25 per cent of air pollution in Sofia with dangerous fine dust particles is due to uncleaned streets, dusting during construction activities and parking in green areas - the so-called resuspension of soil and dust. In second place with comparable pollution indicators is the share of biomass burning (organic matter, wood, etc.). 19 per cent of fine particulate matter is due to coal burning. Non-urban dust sources contribute 16 per cent of dirty air, and road traffic (exhaust dust) is estimated at 9 per cent in terms of PMF pollution contribution. Industry and gas-fired heating plants each contribute 4 per cent to the average annual values for fine particulate matter.
Nitrogen dioxide pollution is a real problem for Sofia and its citizens are exposed long-term to unhealthily high levels. In 19 out of 27 points, annual average concentrations were found to be above the legal norm. The most seriously affected are those who spend more time near busy roads because the problem is mainly observed near places with heavy motor vehicle traffic. This is not surprising, since the main source of nitrogen dioxide air pollution in cities is generally cars with internal combustion engines.