|Package #||VB-S-C-2018 Ambient Air Monitoring||QBE Nomination Closing Date|
|Title||Ambient Air Monitoring||Tender Issue Date||TBA|
|Bid Closing Date||TBA|
This scope of work is to ensure VNL’s Voisey’s Bay mine site, located in Northern Labrador, is in compliance with the terms and conditions for conducting ambient air quality monitoring in Newfoundland and Labrador. Established through its monitoring requirements, VNL will remain consistent with all other ambient air monitoring stations, as required by the NLDMAE.
In addition to the above, the Contractor will be required to provide certified annual or as required calibrations and servicing for Industrial Hygiene sampling equipment.
This contract is scheduled to begin in 2018 and expire 2021.
3. CRITERIA POLLUTANTS
NOX and NO2
In a combustion process, NOX is produced through three mechanisms, namely thermal NOX, fuel NOX and prompt NOX. Thermal NOX is the primary source of NOX and is formed as a high temperature dissociation and subsequent reaction of nitrogen and oxygen. It is produced in the hottest part of the flame and its formation increases exponentially with the flame temperature. The control of thermal NOX is general achieved through reducing the flame temperature, reducing the residence time or operating under fuel rich conditions. Fuel NOX is formed by the reaction of nitrogen compounds chemically bound in the liquor or solid fuels with oxygen in the combustion air. In the combustion of fuels, fuel NOX can account for up to 50% of the total NOX emissions. Prompt NOX is formed from the rapid reaction of atmospheric nitrogen with hydrocarbon radicals, typically under partially fuel rich conditions. However, quantities can be reduced through combustion staging or by operating under highly oxidized combustion conditions.
NO2 is the primary component of concern in NOX emissions. For example, only about 5% of the NOX emitted from diesel fuel combustion is emitted as NO2. The remainder is emitted as NO, which is subsequently converted to NO2 in reactions with various oxidants and oxygen as the plume is transported downwind from the source. The rate of NO2 formation varies with the time of day, season, temperature, wind speed, solar radiation and the availability of oxidants, all of which help to drive the chemical reactions.
NO2 is a reddish-brown gas with a pungent odour, which upon reaction with other atmospheric compounds becomes a major contributor to smog, acid rain, inhalable particulates and reduced visibility. At significant levels and exposure, inhalation may result in irritation and burning to the skin, eyes, nose and throat. Prolonged exposure may result in permanent lung damage.