**GHOST** (Globally Harmonised Observational Surface Treatment) is a project dedicated 
to the harmonisation of global surface observations (most notably air quality pollutants) 
for the purpose of faciliting greater scientific evaluation by the scientifc community.

The major driving force for the creation of **GHOST** was the desire for cross-network 
standardised metadata. Some of the unique features of **GHOST** are:        
*All metadata is handled as dymnaically changing variables though time.  
*Reported measurement methodologies are referenced to a centrally compiled measurement methodology database - allowing the standardisation of measurement methodologies.  
*Network provided classifications are carefully standardised.    
*All data is passed through robust QC tests, giving detailed QA flags.  

The **documentation** directory contains detailed descriptions regarding the processing 
procedures undertaken.

A summary of the networks currently contained under the umbrella of **GHOST** are 
given here:

| **Network** | **Data range** | **Parameters** |
|   --------  |    --------    |    --------    |
|   **EBAS**  |   1970 - 2018  | sconcc, sconccl, sconcco, sconcec, sconchno3, sconcisop, sconcna, sconcnh3, sconcnh4, sconcno, sconcno2, sconcno3, sconco3, sconcoc, sconcso2, sconcso4|
|  **EIONET** |   2013 - 2018  |                |