diff --git a/scripts/boot_emulator.sh b/scripts/boot_emulator.sh
index 5f7df108..10e607cf 100755
--- a/scripts/boot_emulator.sh
+++ b/scripts/boot_emulator.sh
@@ -3,19 +3,26 @@
 # Creates and boots an emulator that exactly matches the one in our CI. It is recommended
 # to use this as the target device for screenshot tests.
 
-set -euxo pipefail
+set -euo pipefail
 
-[ -n "${ANDROID_SDK_ROOT}" ] || { echo "ANDROID_SDK_ROOT must be set to use this script"; exit 1; }
+[ -n "${ANDROID_SDK_ROOT:-}" ] || {
+  echo "ANDROID_SDK_ROOT must be set to use this script"
+  exit
+  1
+}
+[ -n "${ANDROID_API_LEVEL:-}" ] || { echo "ANDROID_API_LEVEL not defined; defaulting to 30"; }
+
+API_LEVEL="${ANDROID_API_LEVEL:-30}"
 
 echo no | "${ANDROID_SDK_ROOT}"/cmdline-tools/latest/bin/avdmanager create avd \
   --force \
   -n Pixel_XL_API_30 \
   --abi 'google_apis/x86' \
-  --package 'system-images;android-30;google_apis;x86' \
+  --package "system-images;android-${API_LEVEL};google_apis;x86" \
   --device 'pixel_xl'
 
 "${ANDROID_SDK_ROOT}"/emulator/emulator \
-  -avd Pixel_XL_API_30 \
+  -avd "Pixel_XL_API_${API_LEVEL}" \
   -no-window \
   -gpu swiftshader_indirect \
   -no-snapshot \
diff --git a/scripts/setup_environment.sh b/scripts/setup_environment.sh
index 55595f74..0aacc518 100755
--- a/scripts/setup_environment.sh
+++ b/scripts/setup_environment.sh
@@ -1,10 +1,19 @@
 #!/usr/bin/env bash
 
-set -euxo pipefail
+# Installs the latest command line tools and sets up the necessary packages for an Android emulator
+# for API level $ANDROID_API_LEVEL, or API 30 if unspecified.
+
+set -euo pipefail
 
 CMDLINE_TOOLS_URL_MAC="https://dl.google.com/android/repository/commandlinetools-mac-6858069_latest.zip"
 CMDLINE_TOOLS_URL_LINUX="https://dl.google.com/android/repository/commandlinetools-linux-6858069_latest.zip"
 
+[ -n "${ANDROID_SDK_ROOT:-}" ] || {
+  echo "ANDROID_SDK_ROOT must be set to use this script"
+  exit
+  1
+}
+
 if [ "$(uname)" == "Linux" ]; then
   wget "${CMDLINE_TOOLS_URL_LINUX}" -O /tmp/tools.zip -o /dev/null
 elif [ "$(uname)" == "Darwin" ]; then
@@ -13,13 +22,21 @@ else
   echo "This script only works on Linux and Mac"
   exit 1
 fi
+
+[ -n "${ANDROID_API_LEVEL:-}" ] || { echo "ANDROID_API_LEVEL not defined; defaulting to 30"; }
+
+API_LEVEL="${ANDROID_API_LEVEL:-30}"
+
 unzip -qo /tmp/tools.zip -d "${ANDROID_SDK_ROOT}/latest"
 mkdir -p "${ANDROID_SDK_ROOT}/cmdline-tools"
+if [ -d "${ANDROID_SDK_ROOT}/cmdline-tools" ]; then
+  rm -rf "${ANDROID_SDK_ROOT}/cmdline-tools"
+fi
+mkdir -p "${ANDROID_SDK_ROOT}/cmdline-tools"
 mv -v "${ANDROID_SDK_ROOT}/latest/cmdline-tools" "${ANDROID_SDK_ROOT}/cmdline-tools/latest"
 
 export PATH="${ANDROID_SDK_ROOT}/cmdline-tools/latest/bin:${PATH}"
 
-sdkmanager --install 'build-tools;30.0.3' platform-tools 'platforms;android-30'
+sdkmanager --install 'build-tools;30.0.3' platform-tools "platforms;android-${API_LEVEL}"
 sdkmanager --install emulator
-sdkmanager --install 'system-images;android-30;google_apis;x86'
-
+sdkmanager --install "system-images;android-${API_LEVEL};google_apis;x86"