www.smithsonianmag.com/innovation/the-first-at-home-test-for-infected-ticks-could-improve-lyme-disease-diagnosis-180989235

The numbers

First visit

0.539 g CO₂e

Return visit

0.021 g CO₂e

Hosting

verified green

LCP

612 ms

CLS

0.021

TTFB

35 ms

At 10,000 views a month this page emits about 49.2 kg CO₂e a year, roughly 201 km in an average petrol car. The estimate assumes 75% new and 25% returning visitors, a measured cache reload ratio of 4%, and world-average grid intensity. How we calculate this

1. Audit third-party servicessave ~0.182 g/visit (1.98 MB)High impact · moderate effort

   39 third-party domains account for 3.97 MB (89% of the page).

   Remove services that no longer earn their place; load the rest on interaction (facades for embeds, delayed consent-gated tags). Each third party is also a privacy and performance dependency.

   • use.typekit.net697 kB
   • www.googletagmanager.com648 kB
   • a.pub.network427 kB
   • cdn.cookielaw.org404 kB
   • fonts.gstatic.com396 kB
   • www.dianomi.com273 kB

   WSG 3.5: Treat third parties the same as first parties
2. Reduce JavaScript payloadsave ~0.058 g/visit (636 kB)High impact · moderate effort

   54 scripts total 2.54 MB on the wire (8.62 MB decoded). Bundles this size usually carry a lot of unused code.

   Split bundles per route, tree-shake dependencies, and audit with a bundle analyzer or coverage profile. A 25% cut is a conservative target for bundles this size.

   • freestar.bundle.07c3df723be8.js257 kB
   • pubads_impl.js206 kB
   • prebid.js203 kB
   • pubfig.engine.js183 kB
   • gtm.js183 kB

   WSG 3.2: Minify and remove unused codeWSG 3.3: Modularize bandwidth-heavy components
3. Optimize web fontssave ~0.039 g/visit (428 kB)Medium impact · quick fix

   23 font files total 1.22 MB.

   Subset fonts to used glyphs, prefer one variable font over multiple weights, serve WOFF2 only, and consider system fonts for UI text.

   • l152 kB
   • l130 kB
   • l129 kB
   • l79 kB
   • l76 kB

   WSG 2.11: Use optimized web typography
4. Fix caching for returning visitorssave ~0.0044 g/visit (36 kB)Medium impact · quick fix

   On a repeat visit 144 kB of static assets were re-downloaded instead of coming from cache.

   Serve static assets with Cache-Control: public, max-age=31536000, immutable and versioned filenames so returning visitors download almost nothing.

   • 409233Cache-Control: public, max-age=31557600, immutable, s-maxage=31557600 · 41 kB
   • 395557Cache-Control: public, max-age=31557600, immutable, s-maxage=31557600 · 29 kB
   • 407163Cache-Control: public, max-age=31557600, immutable, s-maxage=31557600 · 20 kB
   • 395565Cache-Control: public, max-age=31557600, immutable, s-maxage=31557600 · 20 kB
   • 407163Cache-Control: public, max-age=31557600, immutable, s-maxage=31557600 · 17 kB

   WSG 4.2: Optimize caching and support offline access
5. Upgrade compression beyond gzipsave ~0.016 g/visit (174 kB)Advisory · quick fix

   1.16 MB of text ships gzip-compressed; Brotli or Zstandard would cut roughly another 15-20%, and browsers without them fall back to gzip automatically.

   Serve precompressed Brotli for static text assets (highest level, compressed at build time) and enable Brotli or zstd for dynamic responses; keep gzip only as the fallback.

   • freestar.bundle.07c3df723be8.js257 kB
   • otBannerSdk.js144 kB
   • smithsonianmag.bundle.4b5938623c7c.js94 kB
   • en.json94 kB
   • iab2V2Data.json91 kB

   WSG 4.3: Reduce data transfer with compression
6. Stop downloading the same asset twicesave ~0.0059 g/visit (65 kB)Advisory · quick fix

   8 assets were fetched more than once in a single page load (406 kB of repeated transfer).

   Usually a script injected twice or cache-busting query strings that differ per reference. Load each asset once and let the HTTP cache do its job.

   • v4513226cdae34746b4dedf0b4dfa099e17817915094965 downloads · 57 kB
   • 1Ptug8zYS_SKggPNyC0ITw.woff25 downloads · 242 kB
   • css24 downloads · 8.7 kB
   • css23 downloads · 2.4 kB
   • viewabilityCV.js4 downloads · 19 kB

   WSG 3.2: Minify and remove unused code
7. Set a page-weight budgetAdvisory · moderate effort

   At 4.46 MB per view this page rates F. The findings above list where the weight is.

   Agree a transfer budget (e.g. under 975 kB reaches a B), enforce it in CI, and re-scan after each change to hold the line.

   WSG 3.1: Set goals based on performance and energy impact

Where the bytes are

• JavaScript2.54 MB · 54 req
• Fonts1.22 MB · 23 req
• Data (fetch)299 kB · 23 req
• Images222 kB · 24 req
• CSS86 kB · 21 req
• Other36 kB · 6 req
• HTML34 kB · 5 req
• Data (XHR)11 kB · 15 req