$1.2\mathrm{.}26$ Ice$-$resurfacing machines use internal combustion engines that give off exhaust containing CO and NO$,$ Average CO concentrations measured in local ice rinks have been reported as high as $107$ ppm and as low as $36$ ppm$.$ How do these concentrations compare with an outdoor air quality $1$ h standard of $35$ mg$/$m$\text{'}?$ Assume the temperature equals $20\backslash$deg C$.$

$2.2\mathrm{.}29$ The National Ambient Air Quality Standard $($NAAQS$)$ for sulfur dioxide $($SO$-)$ is $0\mathrm{.}14$ ppm$/(24$ h average$).($a$)$ What is the concentration n ug$/$m$\backslash$deg assuming an air temperature of $25\backslash$deg C$?($b$)$ What is the concentration in moles SO$,$ per $10/$ moles of air?

$3.3\mathrm{.}38$ Copper was used as a fungicide in citrus orchards that are being considered for a stormwater retention project as part of the Everglades restoration effort. Copper accumulates in apple snails, a primary food source of the federally endangered bird called the Everglades Snail Kite.The protessional engineer at BTA Inc. is considering two former citrus production areas for construction of a stormwater treatment areaa $1,500-$acre site with soils having a copper content of $220$ ppm and a $2,000-$acre site with $160$ lb of copper uniformly distributed in the top $6-8$ in of soil. Which site would our female engineer recommend for the project if the ecological threshold to support the Everglades Snail Kite is $85$ mg Cu$/$kg$?$ Ecological threshold means that the soil concentration of copper cannot exceed this value. Assume the plow layer of soil $($upper$6-8$ in$.)$ for the $2,000-$acre site weighs $2,000,000$ lb$]]$

$4.2\mathrm{.}40$ Polycyclic aromatic hydrocarbons $($PAHs$)$ are a class of organic chemicals associated with the combustion of fossil fuels. Undeveloped areas may have total PAH soil concentrations of $5$ ug$/$kg$,$ while urban areas may have soil concentrations that range from $600$ to $3,000$ ug$/$kg$.$What is the concentration of PAHs in undeveloped areas in units of ppm$..?$

$5.2\mathrm{.}46$ In $2018$ landfils in the United States produced approximately $110\mathrm{.}6$ Tg COe of methane emissions. Wastewater treatment plants emitted $14\mathrm{.}2$ Tg COle of methane. $($a$)$ How many pounds and metric tons of methane $($reported as CO$,$ equivalents$)$ did landfills and wastewater plants emit in $2018?($b$)$ What percent of the total $2018$ methane emissions $($and greenhouse gas emissions$)$ do these two sourcesssions in $2018$ were $6,676\mathrm{.}6$ CO$.$b$\mathrm{.}1$contribute $($total methane emissions in $2018$ were $634\mathrm{.}5$ Tg COse, and total greenhouse gas emissions in $2018$ were $6,676\mathrm{.}6$ CO$,*)$

$5$ question total $^^^$