AIR pollution in Essex was higher than Los Angeles and Beijing yesterday as experts warn of continued high levels of pollution today.
Essex Weather Centre says air quality levels remain poor on Thursday, especially in Southern and Eastern parts of Essex.
The 24hr mean pollution level was 7/10 in South Essex yesterday - nearly four times higher than defined World Health Organisation 'safe level'.
Pollution levels are expected to drop to around 6/10 today but the air won't clear completely until a fresh blast of air from the Atlantic on Friday, forecasters say.
Defra has warned people to be braced for "very high" levels of air pollution over the next few days.
Despite the higher levels of air pollution, Wednesday was the hottest day of the year so far with temperatures soaring to 21C.
Today will see highs of 18C inland in Essex and 16C along the county's coast.
- Smog hits Essex... but it's good news for some
- Worst smog in 60 years to hit Essex
- In pictures: Smog hits Essex