\begin{tabular}{lrrrrrr}
\toprule
Outcome & Estimate & OIM SE & HAC(6) SE & HAC(12) SE & HAC(24) SE & HAC(12) 95\% CI \\
\midrule
NO$_2$ & -1.868$^{***}$ & 0.168 & 0.445 & 0.519 & 0.585 & [-2.886, -0.850] \\
CO & -7.128 & 2.971 & 5.793 & 6.315 & 7.158 & [-19.506, 5.250] \\
SO$_2$ & -0.084 & 0.045 & 0.086 & 0.082 & 0.063 & [-0.246, 0.077] \\
O$_3$ & 0.563 & 0.192 & 0.367 & 0.367 & 0.364 & [-0.156, 1.283] \\
PM$_{10}$ & -0.108 & 0.325 & 0.734 & 0.778 & 0.840 & [-1.632, 1.417] \\
\bottomrule
\multicolumn{7}{l}{\footnotesize Stars on estimates are based on HAC(12) p-values.} \\
\multicolumn{7}{l}{\footnotesize $^{*}p<0.10$, $^{**}p<0.05$, $^{***}p<0.01$.} \\
\end{tabular}