Early findings from a new urban pollution study suggest that commuters in Manchester inhale their biggest daily dose of harmful traffic fumes during the morning rush hour.
A team from the Centre for Atmospheric Studies at the University of Manchester took measurements in 2005 and 2006 along some of the citys busiest routes.
The work forms part of the wider CityFlux project, which has involved sophisticated air sampling in major cities in England and Europe over the last two years.
Analysis of all the data collected during the study is continuing, and the full results are not expected to be published until at least the end of 2007.
But initial results appear to show that harmful particles produced by vehicles stay trapped near to ground level during the morning rush hour.
Researchers have observed that in the middle of the day, warm bubbles of air rise up from the city streets. This warm air lifts particles from vehicle exhausts away from the built environment. But earlier in the morning the air is too cold to rise and the particles remain trapped at street level.
The research team hopes the mass of data they have collected during their study will give them a better picture of the type and level of harmful particles city dwellers are being exposed to.
They also hope to discover how and when particles are exported away from Manchester, what factors affect their distribution, and if chemical and physical reactions in the atmosphere affect the toxicity of the particles.
Lead researcher Dr Ian Longley from the School of Earth, Atmospheric and Environmental Sciences will present some initial findings during a lecture to the North West branch of the Royal Meteorological Society tonight (Tuesday 28 November 2006).
Emissions like carbon dioxide affect the climate globally but other emissions are harmful to human health, said Dr Longley. They include gases like nitrogen dioxide but also micro
Contact: Alex Waddington
University of Manchester