Cars and other road vehicles are the single main source of harmful nitrogen oxides. Road transport remains the biggest source of harmful air pollution in the EU despite efforts to reduce emissions over the past decades. A report published by the European Environment Agency (EEA) shows that it is the single main source of nitrogen oxides, carbon monoxide and non-methane volatile organic compounds. It is also the second most important source of PM10 and PM2.5 particles. As well as road transport, manufacturing industries, construction, the residential sector and agriculture are the main sources of air pollution in Europe today, the agency said. The EEA said: "Particulate matter from sources such as vehicle exhausts and residential heating can affect the lungs and harm people of all ages, but it is known to pose an extra risk to those with existing heart and respiratory problems." "Air pollutants are also responsible for the acidification of forests and water ecosystems, and eutrophication of soils and waters—leading to a limited supply of oxygen in rivers and lakes." A spokesperson for campaign group T&E (the European Federation for Transport and Environment) told EDIE: "One of the key reasons that transport is still such a major cause of air pollution in Europe is because transport users rarely have to pay for the pollution they cause." "Currently Member States are forbidden from including pollution charges in road tolls." "The Commission just last month proposed to change the rules, a move that we urge the Parliament and Ministers to support." "There are also some positive signs of change as London and a number of German cities have introduced low emission zones over the last year. But there is still a long way to go." According to the report, nitrogen oxide emissions decreased by 35% between 1990 and 2006, although the rate of decrease was just 1.8% in the final year of that period. Electricity and heat production remains the main source of sulphur oxides emissions, followed by manufacturing industries and construction sources. In contrast, agricultural activities were responsible for the vast majority of ammonia emissions— livestock manure and fertilisers accounted for more than 90% of the emissions.