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The control of climatic conditions in a radiation metrology laboratory is very important. Air pressure, temperature and humidity affect the value of the air density, and, consequently, alter the absorption of the photon radiation. Then, the values of the air kerma K-a, conversion coefficients from K-a to the dose equivalent quantities (h(p,K)(10,alpha) and h(K)*(10)) and their product (H-p(10) and H*(10)) are affected by climatic changes. For low energy X radiation fields, changes in climatic conditions are more critical. The International Organization for Standardization (ISO), via the ISO 4037-4, specifies corrections for air density for all quantities defined in 10 mm depth in tissue for nominal tube potentials varying from 10 kV to 30 kV (inclusive). In this work, we utilized monte carlo method to evaluate the influence of atmospheric air climate parameters on the air kerma measurements, for the ISO low energies, series N and L. Simulations were performed using the MCNPX code version 2.7.d, running under MPI (Message Passing Interface) on a computational cluster. We simulated the air with different humidity levels, and consequently, different densities and elemental compositions. The ISO 4037 reference beams of the Dosimeters Calibration Laboratory of the Nuclear Technology Development Center (LCD/CDTN) were utilized to validate the Monte Carlo simulations.