- Home
- Companies
- Passam Ltd.
- Products
- Passam - Nitrogen Dioxide (NO2) Tube
Passam - Nitrogen Dioxide (NO2) Tube
Nitrogen dioxide is a nasty smelling important air pollutant in urban areas and cities. It contributes to the formation of smog and can severely impact human health if exceeding a certain concentration. Major sources of nitrogen dioxide are the burning of fossil fuels, motor vehicle exhaust, petrol and metal refining, electricity generation and other manufacturing industries. The passive samplers to measure nitrogen dioxide are based on the principle of the NO2 diffusion onto the absorbent triethanolamine. The collected NO2 is then determined spectrophotometrically by the well-established Saltzmann method. Being designed for running without power supply, the samplers are optimized to operate in challenging environments.
The passive sampler to measure long term, i.e. 1 to 4 weeks, nitrogen dioxide consist of a polypropylene tube and is placed in a special shelter to protect it from meteorological disturbances of all kinds.
Short term sampling
The passive sampler to measure short term nitrogen dioxide consists of a polypropylene housing with a specific opening of 20 mm in diameter. A glass fiber membrane is attached and supported by a wire net in order to eliminate all kinds of meteorological disturbances.
The diagram shows the comparison of yearly averages of NO2 diffusive samplers and NO2 measurements of different continuous monitoring sites [2] in Switzerland. Each point is characterized by 50 to 70 diffusive sampler measurements over one year and a complete data set of continuous chemiluminescence monitors.
Specifications
Samplingrate:
0.8536 ml/min corrected to 9oC
0.734 ml/min using LANUV membrane
Working range: 1 – 200 µg/m3
Sampling time: 1 – 4 weeks
Detection limit: 0.3 µg/m3 for 1 month exposure
External influences:
wind speed: influence of wind speed < 10% up to 4.5 m/sec
turbulences at kerbsites: may rise uptake rate, membranes recommended
using protection shelters
temperature: no influence between 5 to 40oC
humidity: no influence between 20 to 80%
Storage: before use: 24 months
after exposure: 6 months
Cross sensitivity: nitric oxide and sulfur dioxide do not interfere peroxyacetyl nitrate will give higher results [ 4]
Expanded uncertainty*: 19.0 % at concentration levels of40 µg/m3