diff --git a/main.py b/main.py
index 6ebe104..4427772 100644
--- a/main.py
+++ b/main.py
@@ -5,6 +5,7 @@ import functools
 import logging
 import os
 import zoneinfo
+from urllib.parse import urljoin, urlencode
 
 from fastapi import FastAPI, HTTPException
 from cachetools import TTLCache
@@ -17,7 +18,6 @@ EASTERN_TZ = zoneinfo.ZoneInfo("America/New_York")
 CACHE_TTL_SECONDS = 900  # 15 minutes
 CACHE_MAX_SIZE = 100
 POLLEN_MAX_INDEX = 12.0
-POLLEN_PERCENTAGE_SCALE = 100
 HTTP_TIMEOUT = 10.0
 DEFAULT_ZIP_CODE = "01970"  # salem, ma
 DEFAULT_LATITUDE = "42.3554334"
@@ -266,10 +266,8 @@ class PollenData:
             period_type = str(period.get("Type", "")).lower().strip()
             if period_type in ["today", "tomorrow"]:
                 index_value = float(period.get("Index", 0))
-                # Convert pollen index to percentage scale (0-100)
-                pollen_percentage = int(
-                    index_value / POLLEN_MAX_INDEX * POLLEN_PERCENTAGE_SCALE
-                )
+                # convert pollen index to percentage scale
+                pollen_percentage = int(index_value / POLLEN_MAX_INDEX * 100)
 
                 valid_periods.append(
                     PollenPeriod(
@@ -313,10 +311,14 @@ class WeatherService:
         if cache_key in weather_cache:
             return weather_cache[cache_key]
 
-        url = (
-            f"https://api.openweathermap.org/data/3.0/onecall"
-            f"?lat={latitude}&lon={longitude}&appid={api_key}&units=imperial"
-        )
+        base_url = "https://api.openweathermap.org/data/3.0/onecall"
+        params = {
+            "lat": latitude,
+            "lon": longitude,
+            "appid": api_key,
+            "units": "imperial",
+        }
+        url = f"{base_url}?{urlencode(params)}"
 
         async with httpx.AsyncClient(timeout=HTTP_TIMEOUT) as client:
             response = await client.get(url)
@@ -393,7 +395,8 @@ class PollenService:
         if zip_code in pollen_cache:
             return pollen_cache[zip_code]
 
-        url = f"https://www.pollen.com/api/forecast/current/pollen/{zip_code}"
+        base_url = "https://www.pollen.com/api/forecast/current/pollen/"
+        url = urljoin(base_url, zip_code)
         headers = {
             "User-Agent": (
                 "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) "