I have 40 years of experience, and specialize in the field of environmental science with specific knowledge in the areas of aerosol science and technology, aerosol measurement and respiratory protection. I have published on such topics as new measurement methods for airborne particles, face seal leak of respiratory protection devices and aerosol deposition in lung. I have testified on generation, dispersion and health effect of aerosol spray. I have invented new aerosol measurement methods and trained many scientists in the field of aerosol science and technology.