As investigators, knowing introduction times of items we find helps narrow down the potential search pattern for the source, and in this case we are 6 weeks into the major usage of surgical masks en-masse. This means that the outer boundary is set at potentially 6 weeks of drifting on currents. We can then overlay the wind and current/tidal action from the past 6 weeks to get a general idea as to potential sources. This is not to assign blame, however if we can locate the source, we can also assume that other similar items that arrived at that time could have travel the same route. When we say similar items, when an item enters the water, its shape and weight play a huge role in where it will end up. Light, high sided items such as plastic bottles and polystyrene boxes have large exposed surfaces that will be mostly affected by the wind whilst heavier items that float lower in the water will be more affected by the current. In the case of masks they likely ended up being blown into the water, but after entering the ocean would largely be affected by current and tidal action with wind only affecting the waters surface.