def _to_DOM(self):
        """
        Dumps object data to a fully traversable DOM representation of the
        object.

        :returns: a ``xml.etree.Element`` object

        """
        root_node = ET.Element("ozone")
        reference_time_node = ET.SubElement(root_node, "reference_time")
        reference_time_node.text = str(self._reference_time)
        reception_time_node = ET.SubElement(root_node, "reception_time")
        reception_time_node.text = str(self._reception_time)
        interval_node = ET.SubElement(root_node, "interval")
        interval_node.text = str(self._interval)
        value_node = ET.SubElement(root_node, "value")
        value_node.text = str(self.du_value)
        root_node.append(self._location._to_DOM())
        return root_node
Dumps object data to a fully traversable DOM representation of the
        object.

        :returns: a ``xml.etree.Element`` object