A small municipal solid waste $($MSW$)$ combustor is proposing a modification to increase its capacity to allow processing of $265$ tons$/$day of MSW$.$ Emissions are expected to be $3\mathrm{.}56$ lb PM$2\mathrm{.}5$ per ton of MSW processed. The facility is located in a rural area that is $2\mathrm{.}0$ km east and $250$ m north of a playground. a$.(15$ points$)$ Estimate the expected concentration of PM$2\mathrm{.}5($in $$g$/$m$3)$ on the playground play structure $($at $3\mathrm{.}0$ m height$)$ under an easterly wind of $4\mathrm{.}6$ m$/$s $($measured at $10$ m$)$ on an overcast day. Assume an effective stack height of $75$ m$.$ b$.(3$ points$)$ Compare this concentration to the potentially relevant regulatory limits and breifly discuss potential implications for control.