Under normal conditions, the capacity of plants to generate negative air ions (NAIs) is very weak. However, stimulation of a pulsed electrical field can result in substantial improvement of the ability for NAI generation. We examined NAI generation in Stromanthe sanguinea, Calathea zebrina, and Hippeastrum rutilum in glass chambers under the natural state and under pulsed electrical field and light stimulation and analyzed the shape of stomata. We found variation in NAI generation by plants due to the different combined parameters of the pulsed electrical field. Each plant has its own optimal pulsed electrical field with a combination of parameters for efficient NAI generation: S. sanguinea with A₃B₃C₃ (A₃, U=1.5×10⁴ V; B₃, T=1.5 s; C₃, τ =65 ms), C. zebrina with A₃B₄C₁ (A₃, U=1.5×10⁴ V; B₄, T=2.0 s; C₁,τ =5 ms) and H. rutilum with A₄B₄C₁ (A₄, U=2.0×10⁴ V; B₄, T=2.0 s; C₁, τ=5 ms). With the application of a pulsed electrical field to plants, the higher the voltage, the greater the capacity for NAI generation. With enhanced light intensity, the ability to generate NAI significantly increased with application of a pulsed electrical field. Without the pulsed electrical field, despite the slightly increased NAI concentration with increasing light intensity, NAI concentration did not differ (P>0.05). Finally, NAI generation was closely related to the characteristics of leaf stomata. Furthermore, a greater degree of stomatal opening and stomatal density was associated with stronger capacity to generate NAI.