Mr. Simon Jones:

Large city centre buildings, shopping centres and supermarkets are highly engineered environments. The relative safety or not of those environments should be quite easily determinable because they have big mechanical ventilation systems where you can set how much fresh air those buildings get. If they are not capable of delivering that, then that is an engineering problem but it should be a determinable risk. I would be confident if they were inspected and those involved worked with the available advice that is out there, those buildings should be able to be made relatively safe.