Is the BBC pollution forecast accurate? The pollution for London is forecast as low every morning.?

It is hard to believe the pollution problem in London is so reduced. The link is http://news.bbc.co.uk/weather/forecast/8 - click on the "5 Day Forecast" tab, then the arrow to the right of the top line (today's weather). Scroll to the bottom and the Pollution says "Low" - unusual in the middle of a heat wave.