A new way of measuring ozone and water vapor in the Planetary Boundary Layer (PBL) is proposed. The method is based on the simultaneous measurement of the Raman backscattering in the UV by O2, N2 and H2O, using a single pump beam at 266 nm. The ozone concentration is retrieved from the differential absorption of the N2 and O2 Raman backscattered signals, while the water vapor is measured using the classical Raman scheme. We present some preliminary results showing daytime ozone measurements in good correlation with a point monitor. | A new way of measuring ozone and water vapor in the Planetary Boundary Layer (PBL) is proposed. The method is based on the simultaneous measurement of the Raman backscattering in the UV by O2, N2, and H2O, using a single pump beam at 266 nm. The ozone concentration is retrieved from the differential absorption of the N2 and O2 Raman backscattered signals, while the water vapor is measured using the classical Raman scheme. We present some preliminary results showing daytime ozone measurements in good correlation with a point monitor.