For years, Bulgaria’s Ministry of Environment and Water kept from the public that the air quality monitoring system in Sofia was compromised and failed to accurately report pollution levels, despite having the relevant information. During this time, thousands of Sofia’s residents suffered health issues, and some likely died prematurely due to the polluted air.

This information came to light after the environmental group "For the Earth" won a legal battle for access to public information (Case No. 4667/2024, Administrative Court, Sofia). The organization had requested the release of a 2022 report, commissioned by the then Minister of Environment, that assessed the locations of air quality monitoring stations in the country. For reasons that remain unclear, this critical information had been withheld from the public for so long.

The report revealed that two of Sofia’s transport-oriented automatic monitoring stations, "Mladost" and "Pavlovo", do not meet the required standards as they are situated too far from the road. This results in lower-than-actual readings of nitrogen dioxide (NO₂) pollution, one of the most significant urban air pollutants in Europe, primarily stemming from transportation.

Ivaylo Popov from "For the Earth" emphasized the urgency of addressing the flaws in the air quality monitoring system, highlighting the need for transparency and public involvement. He called for authorities to hold those responsible for the cover-up accountable, as their actions amounted to a crime against public health.

Results of "For the Earth" measurements with 2021 data on nitrogen dioxide pollution in the city. The problem was not taken into account in the planning of the two circles of the zone with low emissions from transport in Sofia, marked on the graph

The issue with Sofia’s monitoring system isn’t just technical but also administrative. For example, the measuring station previously located at one of Sofia’s busiest intersections, Orlov Most, was moved to the National Institute of Meteorology and Hydrology’s yard in Mladost, a park area, during metro construction nearby. According to the report, the station is now 65 meters away from the nearest curb, significantly exceeding the official limit of 10 meters for accurate measurement. The station was never returned to its original location, likely due to the reluctance of some officials and politicians to implement potentially unpopular measures to curb traffic-related pollution.

The automatic measuring station (AMS) Mladost, which is supposed to measure pollution from transport, is placed in a green area 65 meters from the nearest street, according to the data of the report. The requirements for measuring nitrogen dioxide are that it is a maximum of 10 meters from the curb (the area in red - the distances on the graph are approximate).

"For the Earth" has conducted long-term and short-term measurements, revealing that NO₂ pollution is much higher and more widespread across Sofia than the official system reports. These findings were supported by an international team led by Dr. Axel Friedrich, a prominent European expert in the field.

With NO₂ primarily emitted by vehicles with internal combustion engines, especially diesel, the consequences for residents are severe. Short-term exposure can aggravate respiratory conditions like asthma, while long-term exposure can increase the risk of developing asthma and respiratory infections, even for those without pre-existing conditions. Vulnerable groups such as children, the elderly, people with cardiovascular issues, and pregnant women face the highest risks.

Despite these alarming findings and the visible impact on public health, the Ministry of Environment and Water only released a partial reference from the report, ignoring the full disclosure required by court order. This comes as "For the Earth" continues its efforts to access the complete data.

The environmental organization is now calling for an urgent meeting with the current Minister of Environment and Water to demand action and accountability for the administrative negligence that has put citizens’ health at risk.

The association points out that at the invitation of "For the Earth" earlier in the year, the famous international expert Dr. Axel Friedrich and his team carried out measurements of air purity in various places in Sofia. The peak values ​​of nitrogen dioxide in the capital sometimes reach extremely high levels. This shows that quite a number of highly polluting cars continue to drive in the city.

The problems extend beyond Sofia. Other cities also face issues with their air monitoring systems. The automatic measuring station "Zelen Klin" in Stara Zagora fails to meet transport point criteria due to its distance from the road. Manual checkpoints managed by the Regional Environmental and Water Inspections (REWI) in cities like Pazardzhik, Pernik, Haskovo, Montana, and others have similarly been evaluated as non-compliant. An example in Veliko Tarnovo shows that efforts to relocate a problematic station date back to 2015 and 2018, but nothing was done. Even years later, relocation remains recommended. In Svishtov, Nikopol, Silistra, and Burgas, DAOS systems do not comply with height regulations, according to the findings published by "For the Earth."