This summer's third heat wave is expected to grip much of Greece tomorrow when temperatures are likely to reach 42 Celsius (108 Fahrenheit), the National Meteorological Service (EMY) said yesterday. Meanwhile, environmentalists warned of the impact of a relentless series of forest fires on the atmosphere in the capital, which is becoming increasingly asphyxiating. «The difference in Athens's climate is clear to anyone who has come back from holiday,» said Athens University Professor Matthaios Santamou-ris. «The impact has been dramatic, the climate of this city is tragic but unfortunately we will grow used to it.» Experts blame the increase in the capital's temperatures, and high pollution counts, on the three fires that ravaged large tracts of Athens's three forests - Parnitha, Hymettus and Pendeli - which had acted as the city's natural air conditioners. The only way to ensure that the situation is not aggravated is to curb construction on burnt forestland, restrict the use of pollution-emitting cars and introduce more green spaces to Greece's concrete-filled capital, they say.