Exposure of bakery and pastry apprentices to airborne flour dust using PM(2.5 )and PM(10 )personal samplers

BACKGROUND: This study describes exposure levels of bakery and pastry apprentices to flour dust, a known risk factor of occupational asthma. METHODS: Questionnaires on work activity were completed by 286 students. Among them, 34 performed a series of two personal exposure measurements using a PM(2.5 )and PM(10 )personal sampler during a complete work shift, one during a cold ("winter") period, and the other during a hot ("summer") period. RESULTS: Bakery apprentices experience greater average PM(2.5 )and PM(10 )exposures than pastry apprentices (p < 0.006). Exposure values for both particulate fractions are greater in winter (average PM(10 )values among bakers = 1.10 mg.m(-3 )[standard deviation: 0.83]) than in summer (0.63 mg.m(-3 )[0.36]). While complying with current European occupational limit values, these exposures exceed the ACGIH recommendations set to prevent sensitization to flour dust (0.5 mg.m(-3)). Over half the facilities had no ventilation system. CONCLUSION: Young bakery apprentices incur substantial exposure to known airways allergens, a situation that might elicit early induction of airways inflammation.