3. Air sampling is carried out to assist Industrial Hygenist in assessing employee exposure level to airborne contaminants and to ensure that workplace air is meeting regulatory standards. (a)Briefly explain TWO sampling mediums which are commonly used for collecting gases and vapour samples. (6) (b)State the appropriate time for direct reading instruments to be used as air collector devices. (c)Give THREE instruments and types of analytes which are commonly used for laboratory analysis. (d) State the purpose of conducting air sampling in the workplace. (5) 3. Air sampling is carried out to assist Industrial Hygenist in assessing employee exposure level to airborne contaminants and to ensure that workplace air is meeting regulatory standards. (a)Briefly explain TWO sampling mediums which are commonly used for collecting gases and vapour samples. (6) (b)State the appropriate time for direct reading instruments to be used as air collector devices. (c)Give THREE instruments and types of analytes which are commonly used for laboratory analysis. (d) State the purpose of conducting air sampling in the workplace