DrGregor Stewart

I am a researcher in the Environmental Research Group's Air Quality Modelling team with more than 10 years’ experience in air quality model and emissions inventory development. I am also jointly responsible for development of the London Hybrid Exposure Model (LHEM).

The LHEM extends ERG’s CMAQ-Urban air quality model to provide exposure estimates of people outdoors, in vehicles, on the underground and in residential and commercial buildings. It utilises spacetime-activity data from TfL's London Travel Demand Survey (LTDS), which is generated through interviews with approximately 8,000 households per annum. Weighting factors allow the scaling of the LTDS dataset to represent the population of London.

I have developed our air quality and emissions models in London, and delivered outputs on a range of projects which estimated the impacts of future transport policies on emissions and air quality. These include the London Atmospheric Emissions Inventory (2013, 2016 and 2019 versions), consultations on the Ultra Low Emission Zone (ULEZ) and the London Environment Strategy (LES).