| http://nadp.sws.uiuc.edu/ NADP/NTN– This is a large collection of organizations from around the United States that collect chemical data on precipitation. It is called the National Atmospheric Deposition Program/National Trends Network, and contains useful Isopleth maps of the US. | |
| http://www.aeat.co.uk/netcen/airqual/networks/aciddep.html This is the Acid Deposition Monitoring in the UK website. There are multiple measurement sites across the UK, and includes a data archive, and maps of research points. |