All employers should carry out proper risk assessments of their various work activities and implement appropriate measures, to ensure that the risks identified are minimised or mitigated.
When 24-hour PSI exceeds 300, minimising outdoor work and deferring non-essential work and other haze mitigation measures should remain the primary consideration. However, when outdoor work is unavoidable, suitable masks or respirators should be provided.
When 24-hour PSI exceeds 400, non-essential work should be deferred. If outdoor work is unavoidable, an N95 mask which has a protection factor (PF) of 10 may not provide these workers with sufficient respiratory protection during prolonged outdoor work. As such, respirators with higher PF, such as full face respirators with PF of 50, should be considered in such situations.
Companies should identify and estimate the number of workers who are required to perform prolonged work when PSI exceeds 400, as these workers would require fit-testing and training on the use of the respirators. Companies would need to ensure that sufficient numbers of the respirators are available.