A sample of air analyzed at 0°C and 1 atm pressure is reported to contain 0.02 ppm (parts per million) of NO₂. Assume the gram molecular mass of NO₂ as 46 and its volume at 0°C and 1 atm pressure as 22.4 litres per mole. The equivalent NO₂ concentration (in microgram per cubic meter, round off to 2 decimal places) would be _______