Which of the following can cause a nuisance alarm in photoelectric detectors?

Photoelectric smoke detectors operate by using a light source and a sensor to detect smoke particles. Dust, dirt, and insects can interfere with the light path within the detector, leading to nuisance alarms. When these particles are present, they can scatter the light beam, causing the detector to falsely interpret the presence of smoke.

In contrast, high humidity may affect certain types of detectors, but it generally doesn’t trigger a nuisance alarm in photoelectric detectors specifically. Low temperatures can also affect the performance of smoke detectors, particularly ionization types, rather than causing false alarms in photoelectric detectors. Burning food may produce smoke and can certainly activate a smoke detector, but it is not categorized as a nuisance alarm caused by environmental or maintenance issues related to the detector itself. Thus, the presence of insects and dirt is the most direct cause of nuisance alarms in photoelectric detectors.