Use of low-cost particle counters for cotton dust exposure assessment in textile mills in low- and middle-income countries

Objective: There is a lack of consensus on methods for cotton dust measurement in the textile industry, and techniques vary between countries - relying mostly on cumbersome, traditional approaches. We undertook comparisons of standard, gravimetric methods with low-cost optical particle counters for personal and area dust measurements in textile mills in Pakistan. Methods: We included male textile workers from the weaving sections of seven cotton mills in Karachi. We used the Institute of Occupational Medicine (IOM) sampler with a Casella Apex 2 standard pump and the Purple Air (PA-II-SD) for measuring personal exposures to inhalable airborne particles (n = 31). We used the Dylos DC1700 particle counter, in addition to the two above, for area-level measurements (n = 29). Results: There were no significant correlations between the IOM and PA for personal dust measurements using the original (r = -0.15, P = 0.4) or log-transformed data (r = -0.32, P = 0.07). Similarly, there were no significant correlations when comparing the IOM with either of the particle counters (PA and Dylos) for area dust measurements, using the original (r = -0.07, P = 0.7; r = 0.10, P = 0.6) or log-transformed data (r = -0.09, P = 0.6; r = 0.07, P = 0.7). Conclusion: Our findings show a lack of correlation between the gravimetric method and the use of particle counters in both personal and area measurements of cotton dust, precluding their use for measuring occupational exposures to airborne dust in textile mills. There continues to be a need to develop low-cost instruments to help textile industries in low- and middle-income countries to perform cotton dust exposure assessment