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The levels of NO are around 100–2000 ppm (parts per million) and NO 2 20–200 ppm in a range of 1–10% O 2. The sensor has to be very sensitive to pick up these levels. The main challenges in the sensor development are selectivity, sensitivity, stability, reproducibility, response time, limit of detection, and cost.
Measurements allowed to see that at this road average traffic load of 1000 vehicles per hour, the reduction of nitrogen oxides in the air at ground level was 60%. [4] Some were skeptical about this discovery: in their opinion, it is necessary to reduce the level of harmful substances emissions, and not to eliminate their consequence - smog.
Selective catalytic reduction (SCR) means converting nitrogen oxides, also referred to as NO x with the aid of a catalyst into diatomic nitrogen (N 2), and water (H 2 O). A reductant, typically anhydrous ammonia (NH 3), aqueous ammonia (NH 4 OH), or a urea (CO(NH 2) 2) solution, is added to a stream of flue or exhaust gas and is reacted onto a ...
Nitrogen oxide may refer to a binary compound of oxygen and nitrogen, or a mixture of such compounds: Charge-neutral ... Nitrogen oxide sensor; Sulfur nitrides, ...
Activated carbon has strong affinity for many gases and has an adsorption cross section of 0.162 nm 2 for nitrogen adsorption at liquid-nitrogen temperature (77 K). BET theory can be applied to estimate the specific surface area of activated carbon from experimental data, demonstrating a large specific surface area, even around 3000 m 2 /g. [ 13 ]
The oxide sensor is made up of an inert substrate material and two dielectric layers, one of which is sensitive to humidity. The moisture molecules pass through the pores on the surface and cause a change to the physical property of the layer beneath it. An aluminum oxide sensor has two metal layers that form the electrodes of a capacitor.
A digital thermometer reading an ambient temperature of 36.4°C (97°F) in an unventilated room during a heat wave; a high indoor temperature can cause heat exhaustion or heat stroke in a person. The World Health Organization in 1987 found that comfortable indoor temperatures of 18–24 °C (64–75 °F) were not associated with health risks ...
Titanium dioxide (TiO 2), a semiconductor material shown to exhibit photocatalytic behavior, has been used to remove nitrogen oxides (denoted NO x) from the atmosphere. NO x species, i.e., nitric oxide and nitrogen dioxide, are atmospheric gases that contribute to acid rain and smog formation, both of