danielrosehill/Jerusalem-Air-Quality-Shabbat

Jerusalem Air Quality — Weekday vs Shabbat

Twelve months of 5-minute-resolution air-quality readings from 12 monitoring stations across Jerusalem, formatted for analysing the weekday vs Friday vs Shabbat (Saturday) pattern in urban pollution.

📊 Companion analysis repository: danielrosehill/JLM-Air-Quality-Analysis — exact halachic relabeling, cross-city control analysis (London + New York), and the figure set summarised below. Reproducible scripts included.

The motivation: Jerusalem has a uniquely strong weekly traffic cycle — many streets in observant neighbourhoods empty out from Friday afternoon to Saturday night. This dataset is intended to support quantitative work on the resulting air-quality signal.

Source and attribution

All readings come from the Israeli Ministry of Environmental Protection (המשרד להגנת הסביבה) national air-quality monitoring network, accessed through the public portal at https://air.sviva.gov.il/.

The MoEP / sviva.gov.il site is the canonical source. This dataset is a convenience repackaging of that public data into a tidy parquet file with some derived columns (local time, day-of-week, Shabbat/Friday flags) and 12 months of history pre-aggregated for the Jerusalem stations.

If you use this data in research or downstream work, please cite the Israeli Ministry of Environmental Protection as the original source.

Coverage

• Window: 2025-04-28 → 2026-04-28 (12 months, full year)
• Resolution: 5 minutes (native sensor cadence)
• Stations: 12 active continuous monitoring stations within the Jerusalem region (regionId == 8 in the source system).
• Total valid readings: ~7.1 million (only readings flagged valid by the source system are included; sensor-error / calibration rows are dropped).

Stations

station_id	Name (English)	Name (Hebrew)	Notes
5	Bar Ilan St	רחוב בר אילן	Major arterial through ultra-Orthodox neighbourhood
13	Baka	בקעה	Residential mixed
36	Safra Square	כיכר ספרא	City centre / municipal complex
193	Romema	רוממה	Ultra-Orthodox
310	Central Bus Station Platform 10	רציף 10 תחנה מרכזית	Heavy bus traffic
328	Atarot industrial zone	אזור תעשייה עטרות	Industrial / north
458	Devorah HaNevia St	רחוב דבורה הנביאה	Residential
547	Highway 16 / Beit interchange	כביש 16-מחלף בייט	Highway interchange
568	Rockefeller Museum	מוזיאון רוקפלר	East Jerusalem corridor
607	Beit Safafa	בית צפאפא	South-east neighbourhood
623	Atarot Eden	עטרות עדן	North; partial coverage from 2025-08
635	Bezalel St	ירושלים, רחוב בצלאל בזק	City centre; partial coverage from 2026-02

Full station metadata is in stations.csv.

Pollutants and parameters

Per-station coverage varies — not every station measures every parameter. The full set present in the dataset:

code	pollutant_en	typical units
NO	Nitric oxide	ppb
NOX	Nitrogen oxides	ppb
NO2	Nitrogen dioxide	ppb
CO	Carbon monoxide	ppm
O3	Ozone	ppb
SO2	Sulphur dioxide	ppb
PM2.5	Fine particulates	µg/m³
PM10	Coarse particulates	µg/m³
TSP	Total suspended particulates	µg/m³
Benzene	Benzene	ppb
Toluene	Toluene	ppb
Temp, ITemp, RH, WS, WD	Meteorological co-variates	—

Schema

The dataset ships two parquet tables: a long-format table of raw readings with halachic labels, and a wide-format hourly table with derived AQI and activity-isolating composite indices.

data/readings.parquet — long form (one row per station × timestamp × pollutant)

column	type	description
station_id	int	MoEP station identifier
station_name_he	string	Station name in Hebrew
station_name_en	string	Station name in English
station_lat, station_lon	float	Station coordinates (WGS-84)
timestamp	timestamp[UTC]	Reading timestamp in UTC
timestamp_local	timestamp[Asia/Jerusalem]	Same instant in local time (handles DST)
dow	int8	Day of week, Sun=0 … Sat=6 (Israeli convention)
hour	int8	Local hour 0–23
is_friday	bool	Calendar Friday
is_shabbat	bool	Exact halachic Shabbat: candle-lighting → tzeit hakochavim, weekly Shabbatot only (Hebcal, Jerusalem times)
shabbat_or_chag_exact	bool	Either Shabbat or any chag with driving prohibition, exact halachic windows
is_yom_tov	bool	Inside a chag window (Pesach, Shavuot, Rosh Hashana, Sukkot, Shemini Atzeret)
is_yom_kippur	bool	Exact Yom Kippur window — broken out from is_yom_tov
is_pre_shabbat	bool	2-hour window before candle-lighting (erev-Shabbat shopping rush)
is_post_havdalah	bool	2-hour window after havdalah (post-Shabbat rebound)
segment	string	Mutually-exclusive bucket: weekday, pre_shabbat, shabbat, post_havdalah, yom_tov, yom_kippur (priority-ordered, highest wins). The recommended grouping column.
holiday	string | null	Name of any Jewish holiday for that local date (joined with ; if multiple)
pollutant	string	Source code (e.g. NO2, PM2.5)
pollutant_en	string	English long name
pollutant_he	string	Hebrew long name
pollutant_id	int	MoEP pollutant identifier
value	float64	Reading value
units	string	Reading units

⚠️ Schema change vs earlier revisions: is_shabbat is now the exact halachic flag (candle-lighting → havdalah). The old naïve "calendar Saturday" semantics are no longer carried — use dow == 6 if you need that. New columns: is_yom_kippur, is_pre_shabbat, is_post_havdalah, segment.

data/aqi_hourly.parquet — wide form (one row per station × hour)

Pivots the long parquet to one row per station-hour with all measured pollutants as columns, then adds EPA AQI sub-indices, the composite EPA AQI, and two activity-isolating indices.

column group	columns	description
Identifiers	station_id, station_name_en, station_lat, station_lon, hour_bin, dow, hour	One row per station × UTC hour
Halachic labels	is_friday, is_shabbat, is_pre_shabbat, is_post_havdalah, is_yom_tov, is_yom_kippur, segment, holiday	Same semantics as the long parquet
Hourly pollutant means	pm25, pm10, no2, no, nox, co, o3, benzene, toluene, tsp	Mean over the hour, native units (PM in µg/m³, gases in ppb / CO in ppm)
AQI averaging windows	pm25_24h, pm10_24h, o3_8h, co_8h	Rolling means as required by EPA AQI breakpoints
EPA AQI sub-indices	aqi_pm25, aqi_pm10, aqi_o3, aqi_no2, aqi_co	Linear-interpolated per-pollutant sub-indices using EPA breakpoints
Composite AQI	aqi_epa, aqi_dominant, aqi_category	Max of sub-indices; name of the pollutant driving it; verbal band (Good / Moderate / Unhealthy / …)
Canadian AQHI	aqhi, aqhi_band	Health Canada's additive, mortality-risk-weighted index of NO₂ + O₃ + PM2.5 (3-hour rolling means). Computed at city level (no single Jerusalem station measures all three pollutants) and broadcast to every station-row at that hour. Bands: Low 1–3, Moderate 4–6, High 7–10, Very High 11+.

data/weather_hourly.parquet — meteorological covariates

Hourly weather from Open-Meteo's Historical Weather API (ERA5-backed reanalysis), one row per (city, timestamp_utc):

column	description
city	Jerusalem, London, or New York
timestamp_utc	UTC hour
temperature_2m	°C at 2 m
relative_humidity_2m	% at 2 m
wind_speed_10m	m/s at 10 m
wind_direction_10m	degrees at 10 m
pressure_msl	hPa, sea-level reduced
boundary_layer_height	m — most important variable for surface pollution (low BLH traps emissions)
precipitation	mm

Used for meteorological normalisation in jlm_deweathered.parquet and control_deweathered.parquet.

data/jlm_deweathered.parquet and data/control_deweathered.parquet — meteorology-controlled series

Per-station, per-pollutant, per-hour pollutant series after Random Forest meteorological normalisation following the openair deweather::buildMod workflow. Each row contains:

column	description
station_id (or location_id+city for controls)	Station
timestamp_utc	UTC hour
pollutant_en (or pollutant)	Pollutant
value_raw	Raw hourly mean concentration (same units as original)
value_dw	Deweathered concentration: raw − RF_predicted + mean(raw)
units	Native units
(Jerusalem only)	is_shabbat, is_yom_tov, is_yom_kippur, segment, dow, hour

Method. A Random Forest is fit per pollutant per city, regressing hourly concentration on weather covariates (T, RH, wind speed, wind direction sin/cos, pressure, BLH, precipitation), seasonal day-of-year (sin/cos), and station ID. Hour-of-day and day-of-week are deliberately excluded from the feature set — they would let the model absorb the diurnal traffic cycle and the Shabbat / weekend effect along with weather, eliminating the very signal the analysis is trying to measure. Day-of-year stays in to capture seasonal trend (winter heating, summer photochemistry).

Subtracting the model's prediction from the raw value gives a residualised series whose Shabbat-vs-weekday contrast is attributable to non-meteorological factors. R² typically 0.7–0.95 depending on pollutant.

data/deweathered_comparison.csv — summary

Headline weather-controlled Shabbat % drops, Jerusalem only:

Pollutant	Raw drop	After weather control
NO	−80%	−52%
NOx	−69%	−43%
NO₂	−59%	−34%
Toluene	−52%	−17%
PM10	+11%	−12% (paradox flips)
Benzene	−27%	−9%
PM2.5	+28%	−4% (paradox dissolves)
CO	−12%	−4%
O₃	+3%	+1%

Roughly half the raw NO₂ drop is real, the rest is weather. Both PM paradoxes (PM2.5 and PM10 going up on Shabbat) dissolve once meteorology is controlled — they were dust-event artefacts, not Shabbat effects. | Traffic-Combustion Index | tci, tci_n_inputs | Mean of per-station z-scores (vs segment == 'weekday' daytime baseline) of NO₂, NO, NOx, CO, benzene, toluene. Negative = below the workweek norm. | | Photochemical/Dust Index | pd_index, pd_n_inputs | Mean of z-scores of O₃ + PM2.5. Moves opposite to TCI on Shabbat — captures the "wrong-way" pollutants. |

The two custom indices are not standards. They exist because the EPA composite AQI is dominated by particulates here and barely moves on Shabbat, which obscures the (very real) drop in traffic-attributable pollutants. TCI is the cars-and-construction signal; PD-Index is the photochemistry + long-range-transport signal that goes the other way.

AQI methodology in one paragraph. Hourly station means are computed from the long table. PM2.5 and PM10 are 24-hour-rolling-averaged before applying their breakpoints; O₃ and CO are 8-hour-averaged; NO₂ uses the 1-hour value directly. Each pollutant produces a 0–500 sub-index via linear interpolation between the EPA breakpoint table; the composite AQI is the maximum sub-index at that station-hour. EPA's standard category bands (Good ≤ 50, Moderate ≤ 100, Unhealthy for sensitive ≤ 150, Unhealthy ≤ 200, Very Unhealthy ≤ 300, Hazardous ≤ 500) are applied to the composite. SO₂ is not included because Jerusalem stations do not report it.

Quick start

from datasets import load_dataset

ds = load_dataset("danielrosehill/Jerusalem-Air-Quality-Shabbat", split="train")
df = ds.to_pandas()

# Mean NO2 by day of week, for Bar Ilan St
import pandas as pd
no2 = df[(df.station_id == 5) & (df.pollutant == "NO2")]
print(no2.groupby("dow")["value"].mean())

Or directly with pandas / pyarrow:

import pandas as pd

# Long-format raw readings with halachic labels
df = pd.read_parquet("hf://datasets/danielrosehill/Jerusalem-Air-Quality-Shabbat/data/readings.parquet")

# Wide-format hourly table with EPA AQI + Traffic-Combustion + Photochemical indices
aqi = pd.read_parquet("hf://datasets/danielrosehill/Jerusalem-Air-Quality-Shabbat/data/aqi_hourly.parquet")

# Composite-index summary by halachic segment
print(aqi.groupby("segment")[["aqi_epa", "tci", "pd_index"]].mean())

Headline finding: the Jerusalem amplification factor

The most informative way to read this dataset is not the absolute Shabbat % drop in Jerusalem (raw or deweathered), but the ratio of the Jerusalem off-day drop to the averaged London + NYC weekend drop, after controlling for weather. That ratio is the part that isn't captured anywhere else in the literature: every city has a weekend cycle, but the question is how much additional signal Jerusalem's Shabbat carries beyond it.

After meteorological deweathering (Random Forest with T, RH, wind, BLH, pressure, precipitation; openair deweather::buildMod workflow):

Pollutant	Jerusalem	West avg (London + NYC)	Amplification
NO₂	−34 %	−8 %	≈ 4 ×
CO	−4 %	−4 %	≈ 1 ×
O₃	+1 %	+2 %	≈ 0.6 ×
PM10	−12 %	−1 %	≈ 9 × (small denom)
PM2.5	−4 %	−1 %	≈ 7 × (small denom)

NO₂ at ~4× is the clean, defensible headline because both the numerator and denominator are large enough for the ratio to be robust. The PM ratios are real but the Western denominators are small (London + NYC weekend PM barely drops at all), so the ratios are inflated by a near-zero divisor and should be reported with that caveat.

Why ~4× is plausible — what stops on Shabbat that doesn't stop on a Western weekend

The 4× ratio isn't well described as "Jerusalem has a stronger weekend cycle." It's better described as Shabbat being closer to a full traffic-plus-construction ban than a Western weekend is.

The Shabbat intervention removes essentially the entire urban NO₂ inventory at once:

• Private cars — sharp reduction city-wide, near-total in observant neighbourhoods
• Diesel buses — Egged, Superbus, Dan, intercity coaches all stop completely
• Light-rail and high-rise construction — Jerusalem is in an unusually active build-out phase (Green and Blue line works, dozens of high-rise sites), all of which run diesel excavators, drills, and generators six days a week and go silent on Shabbat. Non-road mobile machinery (NRMM) is a known top-3 NO₂ source in growing cities.
• Trucks and freight delivery — near-zero
• Sherut / shared taxis — stopped in observant areas

A typical Western weekend removes only part of this:

• London: cars and freight reduce ~25–30% (not zero), buses run reduced schedule, some central-zone construction restrictions, but domestic gas heating, Heathrow aviation, and most infrastructure works continue.
• New York: traffic and freight reduce ~25–30%, but building heating with #4/#6 fuel oil is uniquely large in NYC's NO₂ inventory and runs continuously regardless of the day of week. JFK/LGA aviation, peaker power generation, and bus service are all weekend-unchanged.

So Jerusalem's Shabbat removes commuter traffic + buses + freight + construction simultaneously, while Western weekends remove only commuter traffic and some freight. A factor of ~4 between those two interventions is what a back-of-envelope source apportionment would predict — and it's what the deweathered data shows.

Why the other ratios sit where they do

• CO ≈ 1× because catalytic converters have pushed urban CO close to the noise floor in all three cities; whatever traffic CO remains is roughly proportional to the day's traffic reduction, and the magnitudes are all small.
• O₃ ≈ 0.6× is the opposite direction — Jerusalem's ozone bump on Shabbat is smaller than the Western weekend ozone bump despite a much larger NOx drop. This is the signature of NOx-saturated urban photochemistry: in this regime, a deeper NOx cut doesn't translate to a proportionally larger O₃ rise, because the local atmosphere flips into a different chemical regime at low NOx.
• PM10 ≈ 9× and PM2.5 ≈ 7× are real in direction but the Western denominators (London/NYC weekend PM drops of −1 to 0%) are too small for the ratio to be quantitatively stable. The right read is "Western PM doesn't have a weekend cycle, Jerusalem PM has a small but real Shabbat cycle once dust is controlled" — the construction halt is probably the dominant mechanism.

What the table predicts about Yom Kippur

Yom Kippur removes the residual that Shabbat doesn't reach: through-traffic on Highway 1, traffic in non-observant West Jerusalem, and Arab-sector traffic in East Jerusalem and the corridors that pass through it. The amplification ratio for Yom Kippur should therefore be even larger than for Shabbat — and the data agrees: combined PM falls 74% on YK, NOx collapses to a near-floor, and composite EPA AQI itself drops to 28 (Good band) which it never does on a regular Shabbat. YK is the natural extension of the same source-removal logic, with the last few categories finally peeled away.

Pre-deweathering Shabbat drops, Jerusalem only

For transparency, these are the raw (uncontrolled) Shabbat % drops, with Friday sitting roughly half-way:

Pollutant	Friday % drop vs Sun-Thu	Shabbat % drop vs Sun-Thu
NO	~40 %	~55 % (range 19–76 %)
NOx	~34 %	~52 %
NO₂	~30 %	~47 %
Toluene	~44 %	~38 %
Benzene	~25 %	~21 %
CO	~7 %	~8 %

Biggest Shabbat drops are in observant West-Jerusalem neighbourhoods (Bezalel ~73 %, Bar Ilan ~55 %, Romema ~52 %); smallest along corridors carrying significant non-observant traffic (Rockefeller Museum ~13 %, Safra Square ~33 %).

Particulates (PM2.5, PM10) do not drop on Shabbat — they often rise. A real signal but confounded by Saharan dust intrusions and weekend grilling; needs its own controlled analysis.

The Saturday row is dramatically lighter than Sun–Thu; Friday is clearly intermediate.

Cross-city comparison

The same 12-month window was pulled from OpenAQ for London (3 stations) and New York (4 stations) and aggregated using each city's own off-day convention.

Off-day vs workweek % change, stratified by pollutant:

Pollutant	Jerusalem (Shabbat exact vs Sun–Thu)	London (Sat+Sun vs Mon–Fri)	New York (Sat+Sun vs Mon–Fri)
NO₂	−62.4 %	−20.0 %	−31.3 %
NO	−62.5 %	—	−57.1 %
NOx	−63.4 %	—	−39.1 %
CO	0.0 %	−13.7 %	0.0 %
O₃	+5.3 %	+8.3 %	+7.1 %
PM10	−16.0 %	−7.1 %	—
PM2.5	−6.8 %	+1.4 %	+1.6 %
SO₂	—	−45.0 %	—

(Cells marked — are missing in OpenAQ's coverage for that station/pollutant combination.)

What the table shows:

• NOx-family (NO, NO₂, NOx) is where Jerusalem stands apart. All three drop ~62–63 % on Shabbat. New York's weekend drop in this family runs ~31–57 % depending on species; London's NO₂ weekend drop is only −20 %. Jerusalem's signal is roughly 2× New York's and 3× London's — far larger than the generic secular weekend cycle.
• O₃ rises slightly on off-days in every city (~+5 to +8 %). Consistent with reduced NOx scavenging when traffic emissions fall — a universal photochemical signature, not a Shabbat-specific effect.
• PM2.5 does not follow the traffic story. Jerusalem shows only a small drop on Shabbat (and the source's is_shabbat calendar-day flag often shows PM2.5 rising). London and NYC weekend PM2.5 actually rises slightly — the same paradox plays out cross-city, suggesting weekend PM is dominated by non-traffic sources (cooking, dust events, secondary formation) everywhere.
• PM10 drops modestly in Jerusalem (−16 %) and London (−7 %), intermediate between the strong NOx signal and the flat PM2.5 signal — coarser particulates carry more road-dust and resuspended traffic dust component than PM2.5.

Bottom line: The Shabbat effect in Jerusalem is real, large, and specifically a traffic-emissions story — the gap between Jerusalem and the secular control cities is widest in NO/NO₂/NOx and narrowest (or flipped) in PM2.5 and O₃. This pattern is consistent with a step-change reduction in vehicle activity rather than any kind of generalised industrial or commercial slowdown.

AQI vs Traffic-Combustion Index

A reading of aqi_hourly.parquet by halachic segment exposes the headline paradox: composite EPA AQI barely moves between workweek and Shabbat because particulate matter dominates the index, and PM in Jerusalem is driven by long-range dust as much as by local emissions.

Segment	EPA AQI	Canadian AQHI	TCI (z)	PD-Index (z)
Workweek (Sun–Thu)	64	4.7	−0.10	−0.05
Pre-Shabbat (2h)	63	4.7	−0.58	+0.20
Shabbat	67	4.4	−0.61	+0.15
Post-Havdalah (2h)	69	4.5	−0.17	+0.06
Yom Tov	71	4.1	−0.66	+0.03
Yom Kippur	28	3.0	−0.90	−0.55

Both standard composite indices — EPA's max-based AQI and Canada's additive AQHI — are dominated by the Jerusalem PM2.5 baseline (which is itself dominated by long-range dust transport). EPA AQI is essentially flat on Shabbat (64→67); AQHI moves a little (4.7→4.4) but not in proportion to the underlying NOx drop, because PM2.5 is the largest term in its additive sum here. The Traffic-Combustion Index plunges by half a standard deviation on Shabbat (and almost a full standard deviation on Yom Kippur), while the Photochemical/Dust Index drifts the other way — exactly as the NOx-saturated urban photochemistry would predict.

The takeaway: standard composites are calibrated for cities where PM2.5 sources are mostly local. In Jerusalem they become "dust meters" that are structurally blind to traffic-emission interventions. An activity-attributable index like TCI is the right tool for evaluating this kind of natural experiment.

Halachic time-window methodology

The dataset ships two Shabbat flags: a coarse calendar one (is_shabbat, all of Saturday) and an exact halachic one (shabbat_or_chag_exact, candle-lighting → havdalah). Real analysis should use the latter, and extend it. The companion analysis repo derives a 6-flag schema from the Hebcal export bundled in this dataset (hebcal-jerusalem.json):

Flag	Window
is_shabbat	candle-lighting → havdalah, weekly Shabbatot only
is_yom_tov	onset → conclusion of biblical chagim with driving prohibition (incl. Yom Kippur)
is_yom_kippur	exact YK window — broken out, since YK is the cleanest natural experiment in the year
is_pre_shabbat	2 hours before candle-lighting — captures the erev-Shabbat shopping rush
is_post_havdalah	2 hours after havdalah — captures the post-Shabbat rebound

Plus a derived segment column resolving these into a single mutually-exclusive bucket: weekday, pre_shabbat, shabbat, post_havdalah, yom_tov, yom_kippur (priority order, highest wins).

Time anchors (Jerusalem, via Hebcal):

• Candle-lighting (Shabbat & chag onset): 40 minutes before sunset (Jerusalem custom)
• Havdalah (Shabbat & chag conclusion): tzeit hakochavim (~3 medium stars)

Why the custom segmentation matters: the naïve "Saturday vs Tuesday" comparison under-states the effect because (a) calendar Saturday includes the post-Shabbat rebound after tzeit, and (b) calendar Friday includes a full normal weekday morning rush. The exact halachic windows eliminate both contamination sources.

Chol HaMoed is intentionally not flagged — driving is permitted, so those days are indistinguishable from weekdays for the traffic hypothesis.

Yom Kippur is broken out because near-universal observance among Israelis (including secular Israelis who drive on regular Shabbat) means the traffic drop is steeper than for any other day — see the 72-hour case study figure in the analysis repo.

In the 12-month window: 50 Shabbatot, 9 Yom Tov windows, 1 Yom Kippur.

Cross-city methodology

Because the secular weekly cycle differs from Jerusalem's, the control cities use their own convention:

City	Workweek	Off-days
Jerusalem	Sun–Thu (segment = weekday, daytime 07–22)	Shabbat (segment = shabbat, exact halachic window)
London / New York	Mon–Fri	Sat + Sun

The cross-city headline metric — off-day % change vs workweek — uses each city's own convention. This is conceptually apples-to-apples ("off-days vs work-days for the local population"), even though calendar boundaries differ. NO₂ values were converted from ppb (Jerusalem source) to µg/m³ (OpenAQ convention; 1 ppb ≈ 1.88 µg/m³ at 25 °C, 1 atm) for overlay charts.

OpenAQ control stations used:

• London: 148, 154, 155
• New York: 384, 626, 857, 1122

Figure set

All figures available in figures/ and in the analysis repo:

1. 01_jerusalem_hour_of_day.png — NOx / NO₂ / PM2.5 hourly curves
2. 02_jerusalem_segment_bars.png — Per-station % change vs workweek by segment
3. 03_jerusalem_dow_hour_heatmap.png — NOx by day-of-week × hour
4. 04_jerusalem_yom_kippur.png — 72-hour line plot bracketing YK 2025
5. 05_jerusalem_pm_paradox.png — NOx falls, PM2.5 doesn't
6. 06_jerusalem_friday_split.png — Friday's intermediate signal concentrates in afternoon
7. 07_jerusalem_segment_distribution.png — Box plot by halachic segment
8. 08_cross_city_no2_weekly.png — NO₂ day-of-week curve, three cities overlaid
9. 09_cross_city_offday_drop.png — Headline cross-city panel

Reproducible via the scripts in danielrosehill/JLM-Air-Quality-Analysis:

python scripts/relabel.py          # 6-flag halachic relabel
python scripts/build_controls.py   # OpenAQ -> tidy control parquet
python scripts/generate_figures.py # All 9 figures

Per-station summary tables are also in analysis/ of this dataset; full preliminary write-up is in analysis/FINDINGS.md.

Caveats and known limitations

• Two Shabbat flags are provided. is_shabbat is the naïve calendar Saturday (Sun=6, Sat=5) and is included for backwards compatibility. shabbat_or_chag_exact is the recommended flag — it uses Hebcal's Jerusalem-specific candle-lighting (Friday eve, 40 minutes before sunset) and havdalah (≈42 minutes after sunset, three medium stars) times, and also covers Yom Tov days. There is a single set of Hebcal times applied to all stations; intra-Jerusalem variation is under one minute and not material for hourly analysis.
• Jewish holidays are flagged but not removed. Use is_yom_tov to exclude the seven major Israeli yamim tovim from your weekday baseline; use holiday to filter by name. Yom Kippur in particular is the cleanest air day of the year (Wed 2025-10-01 was YK 2025); leaving it in inflates the apparent cleanness of the weekday baseline.
• Sensor validity flag is trusted as-is. Only valid: true readings are included; the source system's QC decisions have not been re-verified.
• Two stations have partial coverage: 623 (Atarot Eden) starts 2025-08-06; 635 (Bezalel St) starts 2026-02-05. Their statistics use fewer Saturdays.
• Station 509 (Malchei Israel) is listed as active in the source metadata but returned no historical data over this window and is omitted from data/readings.parquet.
• Region filter: stations were selected by regionId == 8 in the source system. Two stations on the periphery of the region (Highway 16 and Atarot) sit outside the historical city core but are functionally part of the Jerusalem network.

License

The underlying data is published by the Israeli Ministry of Environmental Protection as a public-information service. This dataset is shared under CC-BY-4.0 with attribution to the Ministry as the original data source.

Versioning

• v1 (2026-04-28): initial release. 12 months × 5-min × 12 stations, long-form parquet.
• v1.1 (2026-04-28): adds Hebcal-derived columns shabbat_or_chag_exact, is_yom_tov, and holiday for Jerusalem-precise temporal filtering. Underlying readings unchanged.

External data sources

• Air-quality readings: Israeli Ministry of Environmental Protection (https://air.sviva.gov.il/).
• Shabbat candle / havdalah times and Jewish-calendar metadata: Hebcal, public REST API, Jerusalem (geonameid 281184).