rdrr.io/r/base/names.html" class="external-link">names</a></span><span class="op">(</span><span class="va">air</span><span class="op">)</span> <span class="op">!=</span> <span class="st">"NO2"</span><span class="op">]</span></span>
<span><span class="va">mfdobj_x</span> <span class="op">&lt;-</span> <span class="fu"><a href="../reference/get_mfd_list.html">get_mfd_list</a></span><span class="op">(</span><span class="va">air</span><span class="op">[</span><span class="va">fun_covariates</span><span class="op