The Dolno Ezerovo station in Burgas measured 6.6 µg/m³ of benzene at 7am and 6.23 µg/m³ at 8am on 7 October. There is no alarm threshold for benzene, and the 5 µg/m³ limit is an annual average, the Regional Inspectorate of Environment and Water (RIEW) in Burgas said in reply to journalists' questions.
After 9am the levels began to fall sharply, and over the next few hours they dropped to 0.41 µg/m³. The same day, the RIEW received two reports from residents about a strong, unpleasant smell early in the morning.
One of those who complained is a Burgas resident. Because of the smell, she checked the municipal air quality system and saw the high readings. She says the RIEW treated her report in an offhand and ironic way. She then contacted a media outlet, asking for an official answer on where the smell comes from and what the authorities are doing about it.
She told Bulgarian National Radio (BNR) about the smell: "It usually starts maybe a little after midnight, and in the morning, when we go out to work and to take children to kindergarten, the smell is at its worst."
The RIEW also said there is a clear difference between a high reading and a breach of the limit. Ordinance No. 12 of 2010 sets limits for sulphur dioxide, nitrogen dioxide, fine particulate matter, lead, benzene, carbon monoxide and ozone in the air. It sets alarm thresholds only for sulphur dioxide, nitrogen dioxide and ozone. When these are exceeded, people and authorities are told promptly.
The RIEW says it monitors the air all the time. When readings are high, it studies the recorded data and carries out checks if needed. In September, after reports of unpleasant smells, its experts inspected the main site of Lukoil Neftohim Burgas and drew up a report on an administrative violation.
In Burgas municipality, benzene is monitored around the clock at three points of the National Air Quality Monitoring System, which is run by the Ministry of Environment and Water. They are the automatic stations Meden Rudnik and Dolno Ezerovo, and the RIEW station.
Burgas municipality called the rise short-lived and a one-off that lasted one hour. It said air quality is judged by set indicators and periods, including on a yearly basis. When individual readings rise, the municipality asks the RIEW and the Regional Health Inspectorate (RHI) for information promptly, because they have the powers to find the causes, the possible sources of pollution and the harm.
The woman who filed the complaint said the smell is not new. She said she is more worried by the data on the municipality's website and from its stations, which have long shown very high benzene levels, and that this worries many people in Burgas.
On the harm from benzene, she added: "Benzene is very bad for health, it causes cancer. And with very long exposure to high levels of benzene, it even leads to leukaemia."