Update index.html

safe level

faq/index.html

@@ -147,7 +147,7 @@ <h4>Why these colours?</h4>
               <p>The colour palette was created in collaboration with artist <a href="https://ethanjbrain.com/" target="_new">Ethan Brain</a> who analysed colour themes from two hundred images collected from a google image search for “air pollution”.  As one might intuitively expect, polluted images are dominated by reds, browns and greys and clean images by blues.</p>
               <p>To create the polluted palette from the images the images were analysed to identify the dominant colour themes then, to hone in on images that best represented air pollution, the initial image set was filtered to only include results that fit within the value range of the dominant colour theme.  Dominant colour themes were then extracted from this filtered set and the resulting colours were hand-selected and then tweaked to create a palette that represents increasing values.</p>
               <p>The lightest blue represents the cleanest value of concentrations of less than 5 ug/m³, years in this colour meet the World Health Organisation <a href="https://www.who.int/news-room/feature-stories/detail/what-are-the-who-air-quality-guidelines" target="_new">Air Quality Guideline</a> which was introduced in 2021, all other colours show an exceedance of the guideline values.</p>
-              <P><B>It should be noted that there is NO level of PM2.5 which is considered safe.</B></P>
+              <P><B>It should be noted that even at very low levels PM2.5 can be harmful to health, PM2.5 is a measure of the weight of all the particles below the threshold, it is the composition is the main determinant of the toxicity of the particles.</B></P>
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               <h4>What are the stripes?</h4>