Exhaled breath holds great promise for monitoring human health and for the diagnosis of various lung and systemic diseases, but analysis challenges remain due to the complex matrix of the breath [46, 47] . In this study, different from available devices restricted solely to condensation a simple and low cost EBC collection method using impaction and condensing was developed here for collecting bacteria and virus particles. An important advantage is the reusability of the collection device with a disposable hydrophobic film and an exhalation straw yet with a rapid EBC collection. This would offer the opportunity to collect EBC samples from a large number of subjects, especially during an influenza outbreak or a man-made bioterrorism event, within a shorter time frame. The developed EBC collection method was shown highly successful in detecting bacteria in EBC samples in a clinical setting. The developed EBC collection method was also shown applicable in detecting influenza viruses too. Experimental data here also suggest that exhaled breath, which was shown to contain smaller bacterial particles, could play an important role in airborne transmission of potential diseases. The collection efficiency of other substances including bio-markers (NO,CO, 8isoprostane, hydrogen peroxide, nitrite, volatile organic compounds) using the developed method here is subject to further investigations. In addition, different exhalation modes should be also investigated with the method in collecting EBC. Besides, the dynamics of the air flow, mixing, and effects of temperatures and humidity, condensation, evaporation, growth of particles during the collection as well as the optimal straw length should be also investigated for improving the developed technique. Overall, our developed method here could be easily made available to a laboratory, and have impacts on current practice of EBC collection. Nonetheless, the reported work is a proof-of-concept demonstration, and its performance in non-invasive disease diagnosis such as bacterimia and virus infections needs to be further validated including effects of those influencing factors described. Figure S1 Experimental procedures used in this study include physical characterization and molecular analysis of the EBC collection efficiencies of the device and its pilot application in a respiratory clinic. (TIF) Figure S2 Optical images of EBC samples stained by Acridine Orange (AO): Bacillus subtilis species were used as the positive control and DI water was used as the negative control. (TIF) Figure S3 Detection of H3N2 influenza viruses in EBC samples collected from three human subjects with ID: 1, 2, 3 corresponding to those listed in Table S2 ; In addition, spiked H3N2 virus samples were also amplified; H3N2 viruses were used as the positive control and DI water was used as the negative control. (TIF)  Seasonal influenza vaccination knowledge, risk perception, health beliefs and vaccination behaviours of nurses The relationship between knowledge, risk perceptions, health belief towards seasonal influenza and vaccination and the vaccination behaviours of nurses was explored. Qualified nurses attending continuing professional education courses at a large London university between 18 April and 18 October 2010 were surveyed (522/672; response rate 77·7%). Of these, 82·6% worked in hospitals; 37·0% reported receiving seasonal influenza vaccination in the previous season and 44·9% reported never being vaccinated during the last 5 years. All respondents were categorized using two-step cluster analyses into never, occasionally, and continuously vaccinated groups. Nurses vaccinated the season before had higher scores of knowledge and risk perception compared to the unvaccinated (P<0·001). Nurses never vaccinated had the lowest scores of knowledge and risk perception compared to other groups (P<0·001). Nurses' seasonal influenza vaccination behaviours are complex. Knowledge and risk perception predict uptake of vaccination in nurses. Annual epidemics of seasonal influenza result in about 3-5 million cases of severe illness and 250 000-500 000 deaths worldwide [1] . Healthcare workers (HCWs) can be a key source for influenza transmission in communities and hospitals as they are exposed to both infected patients and high-risk groups [2, 3] . Vaccination is the most effective way to prevent infection and severe outcomes [1] and the principal measure to reduce the impact of epidemics, such as hospitalization, mortality and morbidity [2, [3] [4] [5] . Moreover, studies suggest that the vaccination of HCWs has substantial economic benefits as well as health-related benefits, including reduced absenteeism from work and the extra costs of sick leave and staff replacement [4, 6, 7] .