Free sample. This preview shows 1 of 2 indicator(s) and 3 of 20 economies, and omits the share, trend, momentum and full year-by-year sections. The complete report is at GET /report/macro-air-quality for a small USDC payment over x402, as HTML, JSON or CSV. A free machine-readable cross-section is at GET /preview/macro-air-quality.

Air Quality and Water Stress Report — free sample

Generated: 2026-09-21T08:15:43.449Z | Range: 2015–2025 | Source: World Bank Open Data (CC BY 4.0)

Key findings

This report covers 3 economies and 1 indicator over 2015–2025, containing 27 published observations (82% of the 33 requested year × economy cells). Every figure is reproduced from World Bank Open Data and recomputed into growth, share, trend-fit, momentum, volatility, concentration and data-quality views. Values are also available as JSON and CSV from the same endpoint.

Indicator	Rank 1	Latest value	CAGR / period avg	Trend	Economies	Latest yr
PM2.5 air pollution (micrograms per cubic meter)	China	31.99	-5.3%	-6.0%	3	2023

PM2.5 air pollution (micrograms per cubic meter)

China ranks first at 31.99. Fastest compound growth over the period is United States at -1.8% per year; the slowest is China at -5.3%. Fitted trend is steepest upward in United States (-0.7%, per year of its own mean level, R² 0.134) and weakest in China (-6.0%, R² 0.923). Largest acceleration — last three years against the three before — is China at +6.1% percentage points. The largest covered value is 4.6× the smallest. 3 economies covered; latest observation year 2023. Note: for this indicator a higher value is adverse, so a rising series is not a positive signal.

Trend index (2015 = 100)

Ranked detail

Group mean of the latest reading: 16.80; median: 11.45. Cross-sectional dispersion: 79.4% of the group mean.

#	Economy	Latest	Index	CAGR	Pctile
1	China	31.99	65	-5.3%	100
2	Japan	11.45	85	-2.0%	67
3	United States	6.97	87	-1.8%	33

Index = latest value as a percentage of the first year (100 = unchanged; blank for series that cross zero). CAGR is compound annual growth. Percentile ranks this economy within the covered group.

Trend and dynamics

Economy	Trend %/yr	Trend R²	Momentum	Half-period shift	Volatility	Latest YoY	Peak / trough yr	Outlier years
China	-6.0%	0.92	+6.1%	+3.2%	4.1	+0.3%	2015 / 2022	—
Japan	-1.4%	0.48	+3.5%	+1.8%	5.7	-7.9%	2015 / 2020	—
United States	-0.7%	0.13	-3.5%	+1.6%	6.8	-6.2%	2021 / 2023	—

Trend is the ordinary-least-squares fit of value on year, reported with its R² — how much of the movement the straight line explains, as a percentage of the period mean level so economies of different size are comparable. Momentum is the mean change of the last three years minus the mean of the three before it, in percentage points. Half-period shift compares the second half of the window against the first. Volatility is the standard deviation of year-over-year change. Outlier years exceed 2.5 standard deviations from that economy's own average change.

Data quality

Economy	Published	Expected	Coverage	Span	Missing years
China	9	11	82%	2015–2023	—
Japan	9	11	82%	2015–2023	—
United States	9	11	82%	2015–2023	—

Full year-by-year data

Economy	2015	2016	2017	2018	2019	2020	2021	2022	2023
China	49.47	45.28	43.09	38.51	37.20	33.69	31.92	31.90	31.99
Japan	13.46	12.31	12.19	12.41	12.00	11.24	11.54	12.44	11.45
United States	8.05	7.38	7.69	7.76	7.27	7.74	8.23	7.43	6.97

MethodologySeries are pulled from the official source API and null observations dropped. CAGR = (end/start)^(1/years) − 1. Index uses the first year of the range as 100. Trend is an OLS fit of value on year, reported as a percentage of the period mean alongside its R². Volatility = standard deviation of year-over-year percentage change (percentage points). Momentum compares the last three years against the three before. Share = economy value ÷ sum of the covered economies. HHI = sum of squared shares; its reciprocal estimates the number of evenly sized economies. Cross-indicator correlation is Pearson's r on pooled year-over-year changes.
CoverageRequested: 1 indicator(s) × 3 economies × 11 years = 33 cells; published: 27 (81.8%). Sparse indicators are declared in the Data quality section of each indicator.
FormatsThis document is the HTML delivery. Append ?format=json for the full structured payload (series plus every derived metric) or ?format=csv for the tidy long-format panel. The JSON schema is published at /schema/report.json.
LicenceData © World Bank Open Data (CC BY 4.0), attribution required. Generated by an automated pipeline; research reference only, not investment advice.
DisclaimerValues are reproduced as published by the source; some years may be estimates, nowcasts or subsequently revised figures. Correlations are descriptive statistics, not causal claims.