1 files changed, 43 insertions, 0 deletions
diff --git a/pollutometer-php/src/AppBundle/Utils/Aqi.php b/pollutometer-php/src/AppBundle/Utils/Aqi.php
new file mode 100644
index 0000000..1b324a8
--- /dev/null
+++ b/pollutometer-php/src/AppBundle/Utils/Aqi.php
@@ -0,0 +1,43 @@
+<?php
+/**
+ * Created by PhpStorm.
+ * User: andy
+ * Date: 11/30/17
+ * Time: 11:27 AM
+ *
+ *
+ */
+
+Namespace AppBundle\Utils;
+
+class Aqi {
+    public function calculateAQI($gasName, $concentration, $table) {
+        $bpLow = 1;
+        $bpHi = 2;
+        $bpLowIndex = 1;
+        $bpHiIndex = 1;
+
+        $arr = $table ->{$gasName} ->{'breakpoints'};
+        foreach ($arr as $index => $value) {
+            if ($value <= $concentration && $table->{$gasName}->{'breakpoints'}[$index + 1] >= $concentration) {
+                $bpLow = $value;
+                $bpLowIndex = $index;
+            }
+
+            if ($value >= $concentration && $table->{$gasName}->{'breakpoints'}[$index - 1] <= $concentration) {
+                $bpHi = $value;
+                $bpHiIndex = $index;
+            }
+
+        };
+
+
+
+        $airQualityIndex = (($table->{$gasName}->{'aq'}[$bpHiIndex] - $table->{$gasName}->{'aq'}[$bpLowIndex]) / ($bpHi - $bpLow)) * ($concentration - $bpLow) + $table->{$gasName}->{'aq'}[$bpLowIndex];
+
+        return $airQualityIndex;
+
+    }
+}
+
+?>
+\ No newline at end of file