Knowledge, practices, and health effects of exposure to chalk particles in classrooms among public secondary school teachers in the Johannesburg region

A cross-sectional study involving 239 teachers from 44 public secondary schools was conducted using an online questionnaire. Most teachers (95%) had never received training on exposure to chalk particles, and 76% did not take precautionary measures. Teachers opened windows (20%), frequently washed their hands (16%), and opened doors (15%) to reduce exposure. Despite the lack of training, most teachers (88%) recognised that exposure to chalk particles poses health risks. Most teachers (51%) knew that exposure to chalk particles could occur through inhalation, ingestion, and dermal routes. Chi-squared results indicated no significant differences (p > 0.05) in teachers' age, sex, and work experience regarding their knowledge of exposure to chalk particles. A work experience of 25-30 years was linked to knowledge (AOR: 1.04, CI: 0.27-4.17, p < 0.05). Coughing (19%), throat discomfort (16%), nasal congestion (11%), and headaches (10%) were the most prevalent health symptoms. Work experience of 5-10 (AOR: 3.58, CI: 1.64-8.27, p < 0.05), 15-20 (AOR: 4.76, CI: 1.77-15.25, p < 0.05), and 25-30 (AOR: 3.69, CI: 1.23-13.77, p = 0.03) years was associated with experiencing health symptoms. Due to a lack of training and awareness, teachers unknowingly implemented measures to reduce exposure to chalk particles.