Abstract: An allergen particle detecting apparatus has a sample area through which environmental air is directed. A light beam is directed through the air sample so that portions of the beam will be scattered if any particles are present in the path of the beam. A beam blocking device on the opposite side of the air sample is arranged to block all light except light scattered in a predetermined angular range corresponding to a predetermined allergen particle size range. Light transmitted through the blocking device is detected by a light detector and an alarm output signal is produced if the detected amount of light is above a predetermined level.

Abstract: A light beam is directed from a light source through an air sample so that portions of the beam will be scattered if any particles are present in the path of the beam. A beam blocking device on the opposite side of the air sample is arranged to block all light except light scattered in a predetermined angular range corresponding to a predetermined allergen particle size range. A light focusing lens in front of the light source is arranged to focus the unscattered part of the light beam onto the blocking device. Light transmitted through the blocking device is detected by a light detector and an alarm output signal is produced if the detected amount of light is above a predetermined level. The signal may be used to activate filtering or air conditioning devices.

Abstract: An allergen particle detecting apparatus has a sample area through which environmental air is directed. A light beam is directed through the air sample so that portions of the beam will be scattered if any particles are present in the path of the beam. A beam blocking device on the opposite side of the air sample is arranged to block all light except light scattered in a predetermined angular range corresponding to a predetermined allergen particle size range. Light transmitted through the blocking device is detected by a light detector and an alarm output signal is produced if the detected amount of light is above a predetermined level.

Abstract: An allergen particle detecting apparatus has a sample area through which environmental air is directed. A light beam is directed through the air sample so that portions of the beam will be scattered if any particles are present in the path of the beam. A beam blocking device on the opposite side of the air sample is arranged to block all light except light scattered in a predetermined angular range corresponding to a predetermined allergen particle size range. Light transmitted through the blocking device is detected by a light detector and an alarm output signal is produced if the detected amount of light is above a predetermined level.

Abstract: An allergen particle detecting apparatus has a passageway through which environmental air is directed. A light beam is directed across the passageway so that portions of the beam will be scattered if any particles are present in the path of the beam. A beam blocking device on the opposite side of the passageway blocks any non-scattered portion of the beam while transmitting any scattered portions of the beam along a light path in the apparatus. Any light scattered by allergen size particles will be traveling in a predetermined angular range, and a pinhole device is positioned in the light path so as to transmit only light traveling in that angular range. Light transmitted through the pinhole device is detected by a light detector and an alarm output signal is produced if the detected amount of light is above a predetermined level.