# Air Quality Observations – Adjacent Row Changes

> Air Quality Observations – Adjacent Row Changes is a paid API for AI agents from market.datapackvibe.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-19).

Computes row-to-row (period-over-period) changes in air quality metrics (PM2.5 or humidity) across up to 200 supplied observation records.

## Facts

- Endpoint: POST https://market.datapackvibe.com/x402/assistant-ar-analytics-air-quality-observations-period-change?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-19
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/air-quality-observations-adjacent-row-changes-2e0f28d9
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_FzW3QlopzAuFzXXBviaAg

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability air-quality-observations-adjacent-row-changes-2e0f28d9 -d '<json body>'
```

Example prompt: I have a list of daily air quality readings from several stations — can you calculate the adjacent row changes in PM2.5 for these records: station A on 2024-01-01 with PM2.5=12 and humidity=45, station A on 2024-01-02 with PM2.5=18 and humidity=50, station B on 2024-01-03 with PM2.5=9 and humidity=38?

## When to prefer this

Choose this endpoint when you have a local batch of timestamped air quality observations and need fast, inexpensive period-over-period change calculations without external data enrichment or forecasting. Ideal for auditing sensor logs, spotting consecutive reading anomalies, or generating a simple delta report before further analysis. Not suitable when you need forecast data, cross-dataset enrichment, or more than 200 records processed at once.

## Known failure modes

- Fewer than 1 row supplied — minItems validation failure
- More than 200 rows supplied — maxItems validation failure
- Missing required fields (row_id, station, date, pm25, humidity_percent) — schema validation error
- Invalid date format (not YYYY-MM-DD) — pattern validation error
- Invalid field enum value (not 'pm25' or 'humidity_percent') — enum validation error
- Null numeric values in the selected field — may produce null/undefined delta for affected rows
- Payment failure — x402 protocol payment not completed

## How this service works

Air quality observations - Adjacent row changes: Adjacent row changes for Air quality observations. Up to 200 supplied typed records. Local descriptive analytics; no enrichment or forecast. One of 25 new profiles across 20 shared operations in this industry. 0.01 USDC includes one bounded adjacent row changes report.

## Output

A bounded descriptive analytics report showing the row-to-row change in the chosen field (PM2.5 or humidity_percent) for each consecutive pair of supplied observation records, with no external enrichment or forecasting applied.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "rows": {
   "type": "array",
   "items": {
    "type": "object",
    "required": [
     "row_id",
     "station",
     "date",
     "pm25",
     "humidity_percent"
    ],
    "properties": {
     "date": {
      "type": "string",
      "default": "",
      "pattern": "^\\d{4}-\\d{2}-\\d{2}$",
      "maxLength": 10
     },
     "pm25": {
      "type": [
       "number",
       "null"
      ],
      "maximum": 1000000000000,
      "minimum": -1000000000000
     },
     "row_id": {
      "type": "string",
      "default": "",
      "maxLength": 80,
      "minLength": 1
     },
     "station": {
      "type": "string",
      "default": "",
      "maxLength": 80
     },
     "humidity_percent": {
      "type": [
       "number",
       "null"
      ],
      "maximum": 1000000000000,
      "minimum": -1000000000000
     }
    },
    "additionalProperties": false
   },
   "default": [
    {
     "date": "2026-10-01",
     "pm25": 10,
     "row_id": "row-1",
     "station": "group-a",
     "humidity_percent": 1
    },
    {
     "date": "2026-10-02",
     "pm25": 20,
     "row_id": "row-2",
     "station": "group-b",
     "humidity_percent": 2
    },
    {
     "date": "2026-10-03",
     "pm25": 15,
     "row_id": "row-3",
     "station": "group-a",
     "humidity_percent": 3
    },
    {
     "date": "2026-10-04",
     "pm25": 30,
     "row_id": "row-4",
     "station": "group-b",
     "humidity_percent": 4
    }
   ],
   "maxItems": 200,
   "minItems": 1
  },
  "field": {
   "enum": [
    "pm25",
    "humidity_percent"
   ],
   "type": "string",
   "default": "pm25"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/air-quality-observations-adjacent-row-changes-2e0f28d9/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from market.datapackvibe.com](https://www.zero.xyz/host/market.datapackvibe.com/llms.txt)