The overall goal of the project is to improve the quality of the atmospheric air in the Sofia Municipality by reducing the emissions of PM10 (Particulate Matter) from domestic heating as one of the main sources of air pollution. The specific aim of the project is to replace solid fuel heating devices of households with environmentally friendly alternatives. The project includes preparatory activities necessary for the preparation of the project proposal and main activities. The main activities are: - communication campaigns at the local level - an explanatory campaign will be held among the population about the possibilities of replacing the heating devices with solid fuel, explaining the possible alternative forms of heating and the conditions for including those who wish to participate in the replacement scheme; - technical support for: collecting applications from representatives of the target group for the replacement of heating devices, providing assistance to the potential final recipients of the aid in filling in and submitting the required documents, on-site visits to the homes, signing contracts between the municipality and the final recipients of the aid , to replace solid fuel heating devices with ecological alternatives; dismantling and provision for recycling of high-emission stoves and boilers working with solid fuel; delivery, installation and warranty maintenance of environmentally friendly heating appliances/systems and delivery, installation, warranty maintenance and insurance of photovoltaic systems for personal consumption. The environmental benefits of the project will be expressed in the amount of PM10 emissions saved. The socio-economic benefits are related to protecting the health and increasing the quality of life of the residents of the Sofia Municipality, improving working and recreational conditions for both residents and guests of the municipality, increasing public awareness of air quality issues and others.