ATMOSPHERIC COMPOSITION

Portuguese atmospheric composition network for sampling chemical depositions, gases and aerosols includes the following equipment:

• automatic precipitation collectors for weekly wet and monthly dry depositions; manual NILU collectors for daily precipitation;
• sequential air samplers developed by NILU for sulphur compounds, 24 hour sampling, continuously, based on impregnated filters;
• High Volume air samplers (Hi-Vols) with PM10 impactors for suspended particles in the atmosphere. Ambient air is drawn into a size-selective inlet at a constant flow rate and 24 hour sampling. Particles smaller than 10 μm are collected on a glass fiber filter. Mass concentration is determined by gravimetric method.

As national authority for atmospheric composition activities at GAW/EMEP sations, IPMA has obtained the active participation of CCDR/Alentejo and its certified Laboratory exploring 1 EMEP station at Monte Velho for physical and chemical analysis of atmospheric depositions to characterise the following parameters: pH, electric conductivity, sulphate, nitrate, ammonium, chloride, sodium, potassium, calcium, magnesium, and heavy metals lead, cadmium, nickel, copper, manganese and zinc; also, sulphur dioxide and sulphate in air.

Data are processed and submitted regularly to WMO Data Centers in specific formats.

It is expected to improve and enlarge the IM EMEP network with 2 new stations with automatic continuous ozone analyzers and sequential air samplers for sulphur compounds in air.