​As part of Health Protection’s air quality function, 2 Turnkey Osiris Particle Monitors (OSIRIS: Optical Scattering Instantaneous Respirable Dust Indication System) were purchased in 1999 and 2002. They are designed to continuously monitor particle levels, in particular Total Suspended Particles (TSPs), PM10 (Particles with an aerodynamic diameter of 10 microns) PM2.5 and PM 1.0. The Osiris units sample particles and provide a 15 minute average level. This report presents the results of the 9th consecutive year of monitoring, calendar year 2010 covered by the monitoring period January 2010 to December 2010.