The application of laser-photoacoustic spectroscopy (PAS) to the measurement of the weak IR water vapor absorption as well as to air pollution monitoring is discussed. Good agreement between experimental data on the pressure- and the temperature dependence and theoretical predictions of a H2O dimer model is found for the water vapor continuum absorption. In addition four weak absorption lines could be assigned for the first time as pure rotational H2O transitions. Both a CO laser-based and a CO2 laser-based PAS system are applied to the monitoring of gaseous air pollutants. Results on the sensitivity and the dynamic range of the method are presented. Experimental PAS spectra of specific species are compared to literature data. First examples of gas analysis on the basis of single spectra are discussed.