rp_20150408_day2.png Air pollution forecast for 10 April 2015. Green is fragrant and fresh, purple is murky and mucky.

A mass of highly-polluted air is forecast to sit over the south eastern corner of the UK tomorrow and everyone in the affected area has been warned to avoid strenuous exercise until it has cleared.

Defra's latest air quality map shows that an area covering Brighton & Hove and Eastbourne in Sussex up into Kent and London will suffer from high concentrations of dust, particulates and other pollution. Even the healthy are advised to avoid exerting themselves if they find themselves in red and purple areas. Those with more delicate health should take greater care. Here's the official advice from DEFRA for people finding themselves in areas of very high air pollution:

Health message for at-risk individuals
Adults and children with lung problems, adults with heart problems, and older people, should avoid strenuous physical activity. People with asthma may find they need to use their reliever inhaler more often.
Health message for the general population
Reduce physical exertion, particularly outdoors, especially if you experience symptoms such as cough or sore throat.
Worthing seafront at 5pm today - murky but probably just mist. Worthing seafront at 5pm today - murky but probably just mist.

Dust blowing in from the Sahara and industrial emissions from the Continent will play their part but fumes from vehicles will also join the mix. If you live near or travel along busy roads you are most likely to be exposed to the highest levels of pollution. These are clearly far from ideal conditions to cycle in, especially energetic cycling that leaves the rider breathing hard over a long distance.

One of the reasons I took to an electric bike in 2003 was the air quality along my route from from my home to the office in central London. The congestion zone had just been introduced to alleviate some of the pollution but it was still an unpleasant, grimy, throat-tickling ordeal some days. Some cyclists took to wearing protective masks but I concluded that more or less the same benefits could be enjoyed by not having to breathe so hard by letting an electric motor speed me on my way. I'd also spend less time out on the road and in the murk. Several studies have shown that air quality is worst of all inside vehicles, so driving around not only contributes to the situation, it exacerbates it for both driver and passengers. Taking the cab won't help you.

So, if you really have to cycle to work when there's high pollution, I believe you'll do yourself less harm on an electric bike because you'll be taking in fewer particulates and noxious gases. You'll also be spending less time out in the open thanks to the higher speed of your bike. Of course, if more people used zero-emission vehicles like pedal cycles and e-bikes, there'd be less pollution here and blowing in from the Continent and everyone would benefit. Don't hold your breath for that, at least.