The London Ambulance Service saw a 14% rise in 999 calls for patients with breathing problems yesterday and is still experiencing higher volumes of calls for people with breathing difficulties, asthma and heart problems.
The capital is experiencing "very high" levels of pollution along with the rest of the South East - the highest level recorded by the Department for Environment, Food and Rural Affairs.
LAS said it saw a 14% increase in emergency calls for patients with breathing problems yesterday, from an average of 200 normally to 227 calls.
Deputy medical director Fenella Wrigley said: "More people are calling us with breathing difficulties, asthma and heart problems."
She said people who are young and healthy are unlikely to suffer serious short-term effects from the pollution but anyone with sore eyes, a tickly cough or a dry throat should see their pharmacist or GP if symptoms persist.
- 7 Things You Didn't Know About This Curious Weather Phenomenon
- 12 Incredible Pictures Of London Shrouded In Smog
- 'Sahara Rain' Phenomenon Sees Britain's Air Pollution Levels Spike To Dangerous Highs
- Paris Pollution Measures Will Not Happen In London, Boris Johnson's Office Says
- Visit Buckingham Palace And Be Exposed To The Worst Air Pollution In The UK
"People with asthma may also find that they need to use their inhaler more frequently and I would advise them to have their inhaler with them," she added.
"This is a busy time for us and I would urge Londoners to use us only in an emergency, and anyone with a minor condition should call NHS 111 or seek advice from their pharmacist or GP."
Kay Boycott, chief executive of Asthma UK, said: "The two-thirds of people with asthma who find that air pollution makes their asthma worse will be at an increased risk of an attack following the alarming Defra warning of high pollution levels around the country.
"Asthma UK warns the 3.6 million people at increased risk to be sure they always have a working blue reliever inhaler on them and take their preventer inhalers as prescribed."
Earlier today it was revealed that Prime Minister David Cameron gave up his regular morning jog because of the poor air quality, telling BBC1's Breakfast: "It is unpleasant, and you can feel it in the air.