Wood burning, slow modernization, and Soviet era mismanagement are to blame:
But Bulgaria is hardly alone in having air quality challenges. While Bulgarian cities lead in the concentration of particulates, Poland is a frequent runner-up, and cities in northern Italy lead in ozone, according to separate data provided by the agency.
Over all, in the 10 years measured by the report — from 2002 to 2011 — air pollutants are generally on the decline in Europe. But particulates and ozone remain a problem. An increase in the percentage of urban populations in Europe being exposed to levels of particulate matter from 2010 to 2011 suggested some backsliding, the report said. The development was attributed to dry spells in the period, which slow the dispersal of particulates. But it also could reveal a growing reliance on wood burning for home heating in some countries during the financial crisis, the agency said.