An emergency notification system. The techniques described include the negotiation and use of a cryptographic primitive shared between a service network and a home environment of a station. Testing is performed by operating the ventilation system to cause outside air to flow through the filter and into the enclosure so as to establish positive pressurization inside the enclosure. The amounts of colors for each of the mixed color swatches are defined according to a function of the color parameters of the colors. In one embodiment, a verification system includes a voucher or token database, a recognition subsystem and two transceivers.