TfL Ref: FOI-0032-1718
Thank you for your email received by us on 4 April 2017 asking for information about Rotherhithe Tunnel air pollution monitoring.
Your request has been considered in accordance with the requirements of the Environmental Information Regulations and our Information Access Policy. I apologise for the delay in our response.
I can confirm we do hold some of the information you requested. You asked:
Please can you provide me with pollution monitoring information for February 2017 and March 2017? What levels of vehicle particulates were recorded?
In addition I understand there is Tunnel Environmental System installed to control and monitor day to day vehicle pollution that increases ventilation as necessary. Where are the emissions vented to? What filters are in place to removed pollution from the emissions prior to venting?
The approach road to the Rotherhithe Tunnel (from Lower Road and Jamaica Road) can be severely congested and the air polluted with traffic fumes. Please can you provide to me with any air pollution monitoring information you have for the approach road and "canyon" like tunnel approach on the Southwark side of the tunnel?
Please find attached data sheets for Rotherhithe vent shaft 1 & 2 environmental monitors for CO and NOx. Unfortunately no NOx data is available for vent shaft 2 as we are unable to retrieve the NOx data for this vent shaft from our internal system HORUS.
There are CO, NOx and visibility monitors installed to monitor the air quality inside the tunnel only. Air from inside the tunnel emits from the two ventilation shafts - vent shaft 1 located at Rotherhithe Street (LB Southwark) and vent shaft 2 located at King Edward Memorial Park (LB Tower Hamlets). There are no filters installed in the ventilation shafts, as air quality levels are maintained to safe levels inside the tunnel.
The Nitrogen Oxide levelis measured in parts per million (PPM), the trigger levels switches the ventilation fans on when the NOx level reaches a set value, please refer to the following environmental sensor settings as follows:
- If the ppm value is greater than 6 ppm, the fans will switch on and run at LOW stage until the value decreases
- If the ppm value is greater than 21 ppm, the fans will switch on and run at MEDIUM stage until the value decreases
- If the ppm value is greater than 31 ppm, the fans will switch on and run at HIGH stage until the value decreases
- If the ppm value is greater than 41 ppm, the fans will switch on and run at VERY HIGH stage until the value decreases
The values 1 to 10 on the attached spreadsheets corresponds to the above sensor parameter settings. Please refer to the column heading ‘VALUE’ on the spreadsheet for the ppm reading which is date and time stamped .
Please note, we do not have environmental data for outside the tunnel bore and you will have to request this data from the London Borough of Southwark.
If this is not the information you are looking for, or if you are unable to access it for some reason, please do not hesitate to contact me.
Please see the attached information sheet for details of your right to appeal as well as information on copyright and what to do if you would like to re-use any of the information we have disclosed.
Yours sincerely,
Melissa Nichols
FOI Case Officer
FOI Case management Team
General Counsel
Transport for London