This dataset contains volatile organic compounds (VOC) and ultrafine particle measurements collected onboard several vehicles for the TRANSITION Clean air Network during May 2021 in the London and surrounding area. The particles measured include VOCs captured in the field using thermal desorption tubes, and then analysed into the component species using highly sensitive Markes International GCxGC-TOF-MS system, and ultrafines data captured using a V2000 sensor from National Air Quality Testing Services by Emissions Analytics. Therefore, a much wider range of pollutants have been tested than in standard air quality monitoring. The harm caused by emissions from vehicles to air quality and the health of humans outside is increasing well understood and It is generally accepted that it is a policy priority to remove high-emitting vehicles from the road and to swap for low-emission vehicles or public transport. What is less well understood is the exposure of the occupants in various transportation modes. Aggregate time spent in vehicles is significant, and can be measured in hours per day for certain commuters and professional drivers. Existing research by Emissions Analytics shows that the worst-performing cars can have particle number concentrations more than three times than in the ambient air. With Net Zero, particles are likely to be the dominant traffic pollutant. This dataset contains interior air quality measurements made on a range of modes of transport including diesel and electric trains, the London Underground, diesel and electric buses, and old and new cars, including a battery electric.

A TSI CPC (Condensation Particle Counter) Model 3010 was installed at Halley''s Clean Air Sector Laboratory (CASLab), a mile from the station''s generator, in the (austral) summer of 2019/20 and began collecting data in February as a long term dataset. The inlet is a 3m length of antistatic tubing, with a portion left untethered so that it can move with the prevailing wind. This is to prevent icing of the inlet by allowing the inlet to stay out of the direct line of any snow or ice being blown around. Any movement from the wind should allow any hoar frost that builds up to fall off. The instrument was installed by Joshua Eveson and the primary contact for the dataset is Freya Squires.