Air pollution in central Athens exceeded internationally recommended safety levels on nearly half the days of last year, according to a report by the Environment and Public Works Ministry which also noted a growing smog problem in regions around Attica such as Mesogeia and the Thriaseio Plain. The concentration of particulate air pollution, or PM10 – considered particularly dangerous as the small size of the particles allows them to penetrate deep into the lungs – exceeded the recommended maximum level on 163 days last year, according to a report by the ministry’s pollution monitoring department. On one day in March the concentration of PM10 particles skyrocketed to 550 milligrams per cubic meter, 10 times the 50 mg per cubic meter maximum level. The concentration of PM10 particles also surpassed the limit on the outskirts of the capital – on 147 days in the northern suburb of Lykovrysi and on 124 days in Maroussi. Nitrogen dioxide (NO2), a toxic chemical produced by heavy industry, is also a problem, the same report shows. In the central district of Patissia, concentrations of NO2 reached 92 milligrams per cubic meter, more than double the 44 mg limit. Christos Zerefos, president of the Athens Observatory, said immediate action is needed. «In the early 90s, the problem was temporarily tackled by importing cars with catalytic converters. Since then there have been no other measures in Athens,» Zerefos said, calling for «stricter inspections» on industry to curb toxic emissions. On a brighter note, the ministry’s report noted that concentrations of other chemicals such as carbon monoxide and sulfur dioxide had dwindled, a development attributed to the withdrawal of many old cars from the roads and the switch to natural gas in many households.