Heterogeneous reaction of ClONO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; with TiO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; and SiO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; aerosol particles: implications for stratospheric particle injection for climate engineering