Skip to content
https://lung.org

Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
68
GRADE
D
FIX
3
REVIEW
0
PASS
3
INFO
0
Device:
Mobile Desktop
Checks
6
3 PASS 3 FIX
D
CO2 Per Page Load
Action
1.42g CO2 per view
FIX
1.42g CO2 per view
Warning::
1.42g CO2 per page view
This page transfers 6.0 MB, producing an estimated 1.42g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.04g, network 0.29g, end-user device 1.09g.
Got: 1.42g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 171.0 kg CO2/year
With 10,000 page views per month, this page would generate approximately 171.0 kg of CO2 annually — equivalent to charging 21370 smartphones.
Info::
Green hosting reduces data center emissions

1.42g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 27% of websites

Sustainable Web Design model v4 · Page size: 6.0 MB

Your site
1.42g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.04g
Network
0.29g
End-user device
1.09g
At 10,000 monthly views: Monthly: 14.2 kg · Annual: 171.0 kg · ≈ 21370 smartphone charges
F
Carbon Budget
Action
73th percentile
FIX
73th percentile
Warning::
1.42g CO2 — above the median website (0.60g)
Heavier than an estimated 27% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 73th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

1.42g

73rd percentile

Cleaner than 27% of websites

✗ Above the median website

vs Median 137% more
vs Target 185% more
D
Transfer Efficiency
Action
51% efficient
FIX
51% efficient
Warning::
Transfer efficiency: 51%
An estimated 2993 KB (49%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 2993 KB of unused JavaScript. This wasted data produces 0.69g of unnecessary CO2 per page view.
51% efficient

Total waste: 2993 KB (49% of page weight)

Unused JS 2993 KB

0.69g unnecessary CO2 per visit

Actual transfer 6163 KB
Theoretical minimum 3170 KB
Potential savings 2993 KB (0.69g CO2)

See Deep Analysis sections above for specific optimizations.

A+
Green Hosting
Green (both)
PASS
Green (both)
Info::
Both hosting and CDN use renewable energy
Got: Hosting: Azure, CDN: Cloudflare
Info::
Azure: Verified by the Green Web Foundation
Info::
Cloudflare: 100% renewable energy for global network since 2019
Info::
Green hosting status based on known provider commitments
Green hosting detection uses a curated database of provider renewable energy commitments. This is not a real-time verification. For authoritative checks, visit thegreenwebfoundation.org.
Green Hosting✓ Green Hosted
Hosting Azure✓CDN Cloudflare✓

Azure: Verified by the Green Web Foundation

Cloudflare: 100% renewable energy for global network since 2019

Based on known provider commitments. Verify at thegreenwebfoundation.org

A+
Repeat Visit Weight
98% cached
PASS
98% cached
Info::
98% reduction on repeat visits
Returning visitors download only 113 KB (vs 6163 KB first visit). 212 of 227 resources are served from browser cache, saving 1.40g CO2 per repeat visit.
Info::
Repeat visit: 0.03g CO2 (first visit: 1.42g)
First visit
6163 KB
Repeat visit
113 KB

98% reduction on repeat visits

Saving 1.40g CO2 per returning visitor

212 resources served from cache · 15 resources re-downloaded

A+
Green Hosting
Whether the site is served from green-energy infrastructure
PASS

Green Hosting

This site is hosted on green energy infrastructure

Provider: Cloudflare

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

Send Feedback