asked Her Majesty’s Government:

Whether they will require all the air entering passenger aircraft to be filtered.

My Lords, most modern commercial aircraft are fitted with high-efficiency particulate air filters, which are very efficient in removing airborne contaminants such as droplets, bacteria and large viral particles. Compulsory fitting of filters for volatile organic compounds would have to be required by the regulator, the European Aviation Safety Agency, on the basis of evidence that there was a harmful substance in cabin air and that a particular specification of filter would remove it.

My Lords, I am amazed by the noble Lord’s reply because I have had an enormous amount of correspondence on this from cabin crew and pilots. Is the Minister aware that 50 per cent of the air reaching passenger cabins is unfiltered and contaminated with hydraulic fluid and engine oil containing organophosphates? Will the Government take urgent action to require internationally that all aircraft must be fitted with filters before being passed for service?

My Lords, if 50 per cent of the air reaching passenger cabins were unfiltered and contaminated, as the noble Baroness suggests, I have a feeling that there would be a major crisis in the aviation industry and that very few planes would take off. It is not correct to say that. Studies such as those conducted by the European CabinAir project have shown that the levels of chemical and biological contaminants in aircraft are normally lower than in many work environments, such as office buildings. Compulsory fitting of filters, as suggested by the noble Baroness, for volatile organic compounds would have to be required by the regulator on the basis of evidence. At present, there is no such evidence.

My Lords, in our recent exchanges in your Lordships’ House, the Minister failed to respond to the recommendation of the Science and Technology Committee that there should be an epidemiological study of pilots to ascertain the incidence and prevalence of ill health in air crews. Can he now say what the Government’s attitude is to that recommendation and why he referred to there being question marks over the veracity of some of the research conducted? What research was he speaking of; why does he dispute the findings; and will the Government now take this problem more seriously?

My Lords, we do take this seriously, and that is exactly why we have commissioned further research from Cranfield University. There is a question mark over the veracity of some of the research that has been quoted—in particular, that of Professor van Netten. We remain sceptical of that work because, in correspondence with the department, the professor was unable to give information on the chain of custody for samples that were apparently taken without the knowledge of UK airlines. As to the epidemiological survey to which the noble Lord referred, there are some difficulties with the methodology. Those need to be very carefully considered and I understand that further thought is being given to them.

My Lords, I am surprised that the Minister is not resorting to epidemiology as a backstop. Having been through interminable sheep dip and Gulf War veteran cases involving epidemiological studies, which have delayed the answers, does he not agree that epidemiological studies conducted in line with clinical studies, such as those being conducted by Dr Mackenzie Ross at University College Hospital, London, are the way to find the answer to ill health? Will he ensure that the doctor is provided with the information that she requires to conduct those studies?

My Lords, I understand the noble Countess’s question about Dr Mackenzie Ross’s approach to this matter but that researcher has not yet provided sufficient information to justify the very rare step of using CAA pilots’ addresses to recruit them for that form of research. That remains a difficulty. We need to keep a sense of proportion about this issue. If the case were as the noble Baroness, Lady Trumpington, made out, I think that there would be a profound problem. There is not a profound problem, and no research has yet substantiated that claim.

My Lords, does the noble Lord accept not only that there is the epidemiology problem but that the situation is made much worse because of the often insufficient distribution of oxygen in airliners? It is known to be much less sufficient in economy class than in first class. Surely that makes the matter a far more urgent one for the Government to consider.

My Lords, oxygen supply is a different question from studies of cabin air quality. Let us try to keep a sense of proportion about this. So far, on the worst estimates possible, a fume event—that is what we are talking about—takes place on fewer than one in 2,000 flights, and there is considerable dispute about what the quality of such a fume event might be. I have written to the noble Baroness, Lady Trumpington, on the oxygen issue. There is no evidence to suggest any variation at all in the level of oxygen supply, and my understanding is that the suggestion that the crew somehow interfere with the supply of oxygen is not true either.

Well, my Lords—

My Lords, is it not relevant—

Order!

My Lords, I say to my noble friend that I feel the House wants to move on to the next Question.