Answer
Manual samplers are prone to effects of temperature, speed of wind and air concentrations.
Explanation
Manual samplers face several challenges that can act as drawbacks to obtaining accurate results. They are subjected to effects of sampling duration where long sampling times are needed to obtain adequate mass for detection. Manual samplers face challenges when measuring non-volatile species because particles are observed into the adsorption medium at a slower rate of diffusion.
I think there is a typo because I've never seen HSO4 2- before in my life. It should be HSO4-. For that, H is 1+ and each Oxygen is 2-0 totaling 8-. So the oxidation state of sulfur +1 - 8 = 7
So the oxidation state of sulfur is +6
This is the thing called the mass number of the thing
