Anthropogenic and natural constituents in particulate matter in the Netherlands

Generally, a considerable conformity in the chemical composition of PM_2.5 (and PM₁₀) is observed. From all constituents present in PM_2.5, the secondary inorganic aerosol is the most dominant (42–48%), followed by the total carbonaceous matter (22–37%). Contributions from sea salt (maximum 8%), mineral dust and metals (maximum 5%) are relatively low. For the first time, a detailed overview of the composition of the coarse fraction can be presented. Compared to the fine fraction, contributions of sea salt, mineral dust and metals are larger resulting in a more balanced distribution between the various constituents. Through mass closure a considerable part of the PM mass could be defined (PM_2.5: 80–94%). The chemical distribution on days with high PM levels shows a distinct increase in nitrate as well as in the unaccounted mass. Contributions of the other constituents remain equal or are lower (sea salt) when expressed in percentages. A correspondence between nitrate and the unaccounted mass is observed hinting at the presence of water on the filters. The contribution from natural sources in the Netherlands (at a rural station) was estimated to be 19 to 24% for PM₁₀ and 13 to 17% for PM_2.5.