You can reset your AirVisual account password using the IQAir website or the AirVisual mobile app.
IQAir website
On the iqair.com homepage, click 'Log In' at the top right corner of the screen.
On the login page, simply click 'Forgot your password?' at the lower right side. This will enable you to receive an email to reset your password.
AirVisual App
Within the AirVisual app, from your "My Air" homepage, press the 3-line menu bar at your app's top right corner > 'Sign in' > choose 'Forgotten password?'. You'll then be able to receive an email which allows you to reset your account password.