Longitudinal analysis · live owned archive
Diurnal PM2.5 patterns, paired campus-reference differences and station correlations, with the observation counts needed to judge how much evidence is actually available.
Evidence maturity
Too little calendar duration for a typical daily-cycle or persistent spatial-pattern claim.
Delhi feeds
44
Local hours
39
PM2.5 monitor-hours
1,583
Latest reporting
44
Prospective study separation
Everything currently visible is pilot / method-development evidence. The prespecified primary study window begins 1 Oct 2026; pre-window observations are excluded from the primary estimand.
Diurnal PM2.5 · Delhi local clock
For each observed local hour, the analysis first takes the median PM2.5 across reporting Delhi station feeds. Those network-hour medians are then grouped by local clock hour across calendar days.
Clock hours repeated on ≥2 days
18/24
Current interpretation
This is not yet a typical Delhi daily cycle. Most clock hours currently represent only one or two calendar days. The graph is useful for validating the analysis pipeline and watching evidence accumulate; it should not yet be used to claim a stable morning/evening pollution pattern.
Station-to-station correlation · exploratory
Pearson correlation is calculated only over local-hour PM2.5 buckets observed at both station feeds. Same-coordinate feeds are excluded from the distribution summary.
Independent pairs · n ≥ 12
941
25th percentile r
0.83
Median r
0.92
75th percentile r
0.96
Interpretation boundary
3 calendar days are represented. The high correlations mostly describe common movement during this short window. They are not yet evidence of persistent spatial structure. Short-window negative correlations can also be unstable.
Highest observed r
Rohini, Delhi - DPCC × Wazirpur, Delhi - DPCC
r 1.0038 shared local-hour PM2.5 buckets
Commonwealth Sports Complex, Delhi - DPCC × Okhla Phase-2, Delhi - DPCC
r 1.0038 shared local-hour PM2.5 buckets
Sirifort, Delhi - CPCB × Okhla Phase-2, Delhi - DPCC
r 1.0038 shared local-hour PM2.5 buckets
CRRI Mathura Road, Delhi - IITM × Jawaharlal Nehru Stadium, Delhi - DPCC
r 1.0038 shared local-hour PM2.5 buckets
Ashok Vihar, Delhi - DPCC × North Campus, DU, Delhi - IITM
r 1.0038 shared local-hour PM2.5 buckets
Lowest observed r
NSIT Dwarka, Delhi - CPCB × IGNOU_Maidan Garhi, Delhi - DPCC
r 0.0838 shared local-hour PM2.5 buckets
NSIT Dwarka, Delhi - CPCB × Cantonment Area, Delhi - DPCC
r 0.1738 shared local-hour PM2.5 buckets
NSIT Dwarka, Delhi - CPCB × Narela, Delhi - DPCC
r 0.3238 shared local-hour PM2.5 buckets
NSIT Dwarka, Delhi - CPCB × JNU, Delhi - DPCC
r 0.3438 shared local-hour PM2.5 buckets
NSIT Dwarka, Delhi - CPCB × Dwarka-Sector 8, Delhi - DPCC
r 0.3838 shared local-hour PM2.5 buckets
The exemplar table deliberately uses a stricter display threshold of n ≥ 29 shared hours (max of 24 hours or 75% of the observed local-hour window). This reduces attention to very short overlapping series while leaving the pre-specified exploratory distribution unchanged.
Paired campus-reference differences
For every comparator, the difference is calculated hour-by-hour as comparator PM2.5 minus reference PM2.5, using only hours observed at both linked monitors. Positive values mean the comparator monitor was higher during those paired hours.
| Comparator | Shared hours | Mean paired difference | Median difference | Comparator higher |
|---|---|---|---|---|
LHMC Mandir Marg, Delhi - DPCC | 20 | -21.7 µg/m³ | -22.0 µg/m³ | 0% |
ABVIMS Talkatora Garden, Delhi - DPCC | 38 | -4.1 µg/m³ | -3.5 µg/m³ | 21% |
MAMC ITO, Delhi - CPCB | 39 | -3.2 µg/m³ | -3.0 µg/m³ | 33% |
AIIMS Sirifort, Delhi - CPCB | 39 | +11.6 µg/m³ | +10.0 µg/m³ | 100% |
VMMC R K Puram, Delhi - DPCC | 39 | +32.7 µg/m³ | +33.0 µg/m³ | 100% |
Dr BSA Rohini, Delhi - DPCC | 39 | +45.3 µg/m³ | +47.0 µg/m³ | 100% |
What this does not mean
This is a paired comparison of nearby ambient reference monitors. It is not an estimate of indoor campus air, personal exposure, a causal effect of attending a campus, or a health ranking. No p-values or confidence intervals are reported while the archive is this young and strongly temporally autocorrelated.
Reproducibility boundary
This page updates as new hourly observations enter the owned archive. A formal report should state its exact analysis window and, wherever possible, cite a frozen release or export so the result can be reproduced later.
Analysis specification 1.2.0
v2.9 deliberately reports observation counts and descriptive effect sizes without p-values or causal claims. Temporal autocorrelation, station availability, weather and multiple comparisons require a pre-specified inferential plan before formal hypothesis testing.