29 131. Furthermore, Directive 2003/35/EC1, which provides for public participation when certain plans and programmes related to the environment are drawn up, makes it compulsory for the member states to adopt the necessary measures to ensure that the public can get fully involved in devising – and, where necessary, reconsidering – environmental plans and programmes. These measures include informing the public about draft plans and programmes in the sectors of waste, air pollution and the protection of water from nitrate pollution, giving the public the opportunity to voice comments and opinions on these drafts and taking account of results of public participation when making decisions. Air pollution strategy 132. This strategy is based on the premise that air pollution seriously damages human health and the environment: respiratory problems, premature death, eutrophication and damage to ecosystems as a result of the deposition of nitrogen and acidic substances. The pollutants that are considered to raise the greatest public health concerns are tropospheric ozone2 and particulate matter (especially fine particles). 133. When drawing up the strategy, it was impossible to determine a level of exposure to particulate matter and tropospheric ozone that does not pose a threat to human beings. However, there is a conviction that a significant reduction in these substances will have positive effects on public health and benefits for ecosystems. 134. Taking the situation in 2000 as its departure point, the Strategy sets specific long-term objectives (for 2020): a 47% reduction in the loss of life expectancy as a result of exposure to particulate matter; a 10% reduction in cases of acute mortality caused by exposure to ozone; reduction in excess acid deposition of 74% and 39% in forest areas and surface freshwater areas respectively; a 43% reduction in areas or ecosystems exposed to eutrophication. 135. To achieve these objectives, sulphur dioxide (SO2) emissions will need to decrease by 82%, nitrogen oxide (NOx) emissions by 60%, volatile organic compounds (VOCs) by 51%, ammonia (NH3) by 27% and primary PM2.5 by 59% compared with year-2000 levels. 136. Another of the strategy’s aims is to improve European air quality law through the merger into a single directive of Framework Directive 96/62/EC on ambient air (see below), its three "daughter" directives setting the limits for various types of air pollutants and a decision of the Council on exchanges of air quality data between member states3. 1 Official Journal L 156, 25/06/2003, p. 0017- 0025; deadline for transposition 25 June 2005 Tropospheric or ground-level ozone is a colourless and highly irritating gas that forms just above the earth's surface. It is called a "secondary" pollutant because it is produced when two primary pollutants react in sunlight and stagnant air. These two primary pollutants are nitrogen oxides (NOx) and volatile organic compounds (VOCs). NOx and VOCs come from natural sources as well as human activities. About 95 per cent of NOx from human activity come from the burning of coal, petrol and oil in motor vehicles, homes, industries and power plants. 3 Proposal presented by the Commission on 21 September 2005 for a Directive of the European Parliament and the Council on ambient air quality and cleaner air for Europe (COM(2005)447 final). 2