Not more than any typical electric appliance... The strength if a magnetic field is proportional to current flow. Electrostatic air filters use high voltage to create an electro-static field, but use relatively little current in doing so. An "electro-static field" is completely different from an electro-magnetic field (which is proportional to current, not voltage) and shouldn't be dangerous for tape. Ionizing air cleaners are safe as long as they are used as intended. As with all electric appliances, they should not be located adjacent to tapes.
I might add that the ozone generated by true "electrostatic" air purifiers is harmful to your health. That is why they are banned in many states.