In a particular region of the earth's atmo- sphere, the electric field above the earth's sur-face has been measured to be 152 N/C down- ward at an altitude of 268 m and 171.5 N/C downward at an altitude of 414 m.The permittivity of free space is 8.85 × 10-12 C2/N · m2. Neglecting the curvature of the earth, cal- culate the volume charge density of the at- mosphere assuming it to be uniform between 268 m and 414 m. Answer in units of C/m3.