In suburban watersheds, "headwaters” begin on rooftops that flow through lawns before entering storm drains that flow to streams. Therefore, water moving through lawns during storms can transport pollutants to downstream ecosystems. Fertilizers added to lawns in suburban watersheds are often targeted as non-point sources of nitrogen pollution to local streams. Interestingly, microplastics, a more recent pollutant of concern, are also abundant in fertilizers and thus can also enter urban headwaters through fertilizer applications. Additionally, both nitrogen and microplastics can also enter lawns via atmospheric deposition associated with vehicle use. Given that these two pollutants can enter suburban watersheds by the same mechanisms, we need to understand drivers of their concentrations in lawns to better mitigate pollutant transport from suburban headwaters. Our objective is to examine the relationship between homeowner fertilizer applications and traffic levels on nitrogen and microplastic concentrations in lawns. Soil samples were collected from 27 different homes in Mount Pleasant, MI that represent fertilized and unfertilized lawns in high and low traffic areas. Soil samples collected in front and back yards were analyzed for soil nitrogen and microplastic concentrations. We found front yards had somewhat higher levels of soil nitrogen- an important consideration as front yards are more vulnerable to runoff from them entering storm drains. There is no clear effect of homeowner reported traffic levels in relation to soil nitrogen levels. There is also no effect of fertilizer applications on soil nitrogen levels. This suggests that there is an aspect of lawn nitrogen inputs we have yet to account for. We hypothesize that microplastic counts will act similarly to nitrogen present in lawns. By assessing both the nitrogen and microplastics present in lawns, we will be better informed about the co-occurrence of two important pollutants in suburban headwaters and the role of traffic and fertilizer applications in shaping those patterns.